I've read about an interesting way to string a racket at high tension without putting high stress on the corners of an isometric headshaped racket.

The article was by the official stringer for the Danish national team, and he said that at extreme tensions approaching 30 lbs, he only tensions the centre 8 strings at those tensions, then lowers the tension gradually on the outer strings.

This seems to make a lot of sense, since most good players will only hit with the centre of the racket and the stress on the corners of an isometric head will come from the strings towards the outside of the racket. I've seen so many Yonex iso heads break at the top corners because of tensions in the 26-28 lbs range, I want to try this new technique.

Has anyone out there tried it, either as a stringer or a player?

Thanks

Interesting...did he mentioned by how much did he lower the tension as he moves to the outside? (1 lbs per two strings?)

How about the cross? Did he string them from the centre out using the same technique?

This is similar to what tennis stringers call "proportional stringing" method where the tension of the strings are intentionally lowered as you string away from the middle of the racket face.

The other advantage of this method is that is produces a "softer" string bed and thus increases the sweetspot area.

see http://talk.tennis-warehouse.com/discussions?13@185.ggcYarG7j1B^8@.ee8bb9b

Hmmm... Kinda 180' opposite the way I learned about stringing. In my drop weight string machine guide, it told me to add 3-5 lbs of tension on the last outter string to prevent "losing tension" while doing the knots.

Also, less say no matter lower or higher the tension for the out strings, since it still the same piece of string. I assume very soon, all strings will have the same tension, isn't it???

Originally posted by LazyBuddy
Also, less say no matter lower or higher the tension for the out strings, since it still the same piece of string. I assume very soon, all strings will have the same tension, isn't it???

Would be interesting to know how fast and to what level of perfection the stringbed will smoothen out to one tension.

All depending on the friction between strings and grommets. Maybe due to less friction muscle power frames have a more consistent stringbed.

Hmm maybe the next idea for a new racket line, wheel power : instead of grommets wheels that lead the string :D

In my drop weight string machine guide, it told me to add 3-5 lbs of tension on the last outter string to prevent "losing tension" while doing the knots.

A test would be to grab a racket that has been strung for a longer period and where directly after stringing was lack of tension on the outer string due to doing the knot and see if that outer string is tight now.

i have seen this method used by a couple of good stringer. i have watched Emmy's father and Luxis (Mr. Ng) string, and they both lower tension as they move away from the center string. the result of Luxis stringing is one of the best i have seen. there is a certain repel coming from the string that feels very nice. i can't vouch for Emmy's father stringing as i have never tried it.

as for how many pounds to lower, i don't know. perhaps someone should pick Luxis' brain for it.

as for why and how this method works. the first observation is that the repulsive power from a racket is determined by the natural frequency of the string. strings with different natural oscillation frequency will react differently when struck. the natural frequency of the string is determined by a few factors, the length of the string, the tension of the string, the thickness&material of the string.

given that fact, also observe that the length of the middle string and outer strings are different. thus, if strung at exactly the same tension, the outer string will have a higher oscillation frequency than the center strings, thus creating a string bed with uneven repulsion. i believe this will make the sweetspot smaller and if overly done, will make the racket feel very "dead".

lowering the tension of the outer string will cause the tension across the string bed to be more even and thus enlarging the sweetspot and make the racket more alive.

i don't believe many stringers knows about this fact. and it is for this one reason that i am considering re-purchasing a stringing machine. the quality of stringing i have tried is worse than what i expected. and sending all rackets to Luxis doesn't seem to be too viable a route..... but then, i don't want a cheap drop weight machine again as they are such a pain to use. and a good crank machine is rather expensive... :(

Hmmm... What should I do then???

I mean, sounds like my method of "put 3-5 lbs extra on outter string" is a bad way to string, say, further eliminated the size of sweet spot...

Should I just on purposly put all string to be even tension, but just 1 or 2 lbs higher than my desired ones? Say, if I want to string @20 lb, I will put 21,22 lb evenly on every single string???

While, I have to find a way to survive on my drop weight machine for now...

extra tension on the outer string is definitely a no no, IMHO. when i had a machine, i wasn't aware of the uneven tension technique and i string with even tension. the result was ok, not spectacular. nothing like Luxis' stringing.

what i like about using a crank machine for this situation is that the crank machine has a little dial at the end to fine adjust tension. you just rotate this little knob to lower the tension as you go. for a drop weight, one must unscrew the weight, move it to the right place, and then tighten again. definitely a pain to have to perform on each string.

so the cheapest and decent quality crank machine is the Alpha 3000. BadmintonAlley has it for around $625. nice that he is local so i can just go there and pick it up. maybe he will even give me a discount. but heck, that's a lot of money.

Ok, guess start from now on, I will put 1-2 lbs extra, but even distributed among all strings for now.

hmm so it seems like the right way to string here is to start w/ the middle strings, and lower the tension slightly, say 1/2 lbs for every couple of strings out and so on? sounds like a good project to try. Luckily I do have a racquet of my own that does require stringing. If we work with this method, suppose we want a 24lbs tension, we would start w/ 24 in the middle and by the time we reach the edge, it would be 20 lbs. Also, with this method, do we do the same thing for the cross? That seems a little harder to do for the cross.

jwu,

you can also string the cross from the center out. read my stringing guide.

oh, one more thing i forgot. to determine how many pounds of tension to lower, this is one way to determine it.

after you are done with the main strings, pluck the strings and listen to the tone. or just pluck across the string bed. if the natural frequency is uniform, then all the strings will have the same tone.

the real experiment would be to compare rackets with different tones, try strining one with lowering tone center->side, string one with uniform tone, string one with rising tone, and see which one plays better.

surely, some master stringer somewhere must have figured all these out already.

Originally posted by Yong
Hmm maybe the next idea for a new racket line, wheel power : instead of grommets wheels that lead the string :D


they have that in tennis racquets already.

An chinese elder had told me about this method some 14 years ago, that was before i got my stringing machine. He didn't have reasons to explain it but i knew why right away. Like everything in life, there is no one method for all situation so i dun use this method all the time.

As for luxis, how do they take instruction from customers? or give customers their result? for example if i say i wanted 24 lbs, do i get 24 in the middle or the 24 as an average or 24 all around unless i ask for the special method?

As far as I know, you ask for 24, you get 24 x 26lbs at Luxis.

For the high tension racquets, you get lower tensions as the strings move away from the sweet spot.

Not sure if they do this with the regular tensions....e.g. up to 22-23 lbs.

Kwun, according to my rough calculations, you may only need to string 60 racquets and this can be easily acheived if using BG85 and giving me the racquets to use!!

good point Cheung. if this method is indeed used to increase the sweet spot, and since lower tension generally have larger sweet spots, there will be less need to use it for lower tension.

however, i do remember Emmy's father using it for tension of 22lbs.

Tried the 'lowering tension' method on 2 stringing jobs and i am pleasently surprised about the results.

Main tension : 26 lbs for the middle 4 strings. Tension was lowered on each next string, ending with 20 lbs for the outer strings.
Cross tension : used 2 tensions : 25 for the middle, 23 for the 5 top and 5 bottom strings.
Cross sring was done top to bottom. Want to try from strining from center some time, but with my 2 current swivel clamps, this is impossible, at least, when tensioning every string.
Stringing job was done on a 6-point crank machine.

Compared to the previous one-tension stringing jobs on the same racket (also done by myself), the racket absolutely felt more alive. During play, smashes were harder while control still felt good.

Just a quick question on this "lowering tension" theory. When the string settles after the string job won't the string tension even out eventually? I mean say 4 middle string are strung at 26 and the lowered .25 or .5 for each string won't the string just even out eventually to an average of 24 or 23 unless you constantly string the racquet. Thanks in advance guys.

Cheers,
Nick

Originally posted by Nick
When the string settles after the string job won't the string tension even out eventually? I mean say 4 middle string are strung at 26 and the lowered .25 or .5 for each string won't the string just even out eventually to an average of 24 or 23 unless you constantly string the racquet.


If u r talking about a racket after playing for months, u r right. However, for newly strung racket, due to the huge friction between strings, and gromments, it's very hard for the tensions to be pulled to be even in short period of time. Therefore, as along as the "formation" stay in effective, the sweet spot will be relatively optimized.

However, after certain period of time, depend on how often u use it and how hard the smashes are, the tension will move toward to be equivalent. Well, normally, after several months, we need to re-string it anyway.

I have no experience at stringin, but won't this method damage the racket in anyway???

Originally posted by Xero
I have no experience at stringin, but won't this method damage the racket in anyway???

I don't think so. Unless, u put the forces to be unevenly distributed, like too much tension on the right, but very loose on the left.

But, how could a stringer string a racket w/o even knowing "evenly apply force" first?

I hear that some stringers vary the tension of the mains and crosses to achieve better playability (maybe better durability) of the racquets when stringing beyond 26 lbs. My question is what dangers are inherent in this type of stringing method. Another badminton fanatic friend of mine recommends me not to vary the tension across the main & cross strings and should them constant - all in the name of keeping the racquet balanced. For example, if one were to string 30 lbs, all mains should be 30 lbs and all crosses should be 27 lbs.

Several BF forumers seem to have extensive experience in this type of stringing method. Please enlighten us, the amateurs, the proper way of progressive high-tension stringing . . .

Thanks in advance.

They seem to use progressive tensions to allow the racquet to handle higher tensions. Since the corners of an isometric racquet is weakest, it makes sense to use a lower tension in those sections. I wonder how the racquet plays though... since lower tension generally means more power, areas outside the sweet spot would be more powerful than otherwise, so that the power across the entire racquet face is more consistent?

I think Mr. Ng of Luxis specialize in the art of progressive high-tension stringing. He once stringed my racquets to 30 lbs. The playability was excellent! The string bed was very bouncy even at that high a tension. Compared to my recent experience with constant tension string jobs, the string bed feels dead and my elbow actually hurt a bit and the tension was only 28 lbs X 28 lbs!

to have a good and "uniform" string bed with a big sweet spot, one need to string the racket in such a way that across the string bed, all the individual string segments have similar response.

my theory so far, is that the tension itself is not the main determining factor to the playability of the string. instead, i believe the natural response of the string, kinda like "bounciness" is the determining factor. i skipped the mech engineering class on resonance when in college, but i believe that the natural resonance frequency of the string determines the natural response. (actually, more accurately, the natural response of the string determines the natural resonance frequency via a second order differential equation)

as the racket is more of an oval shape and not square, to string all string segments in equal tension but varying length will produce lower resonance frequency in the middle string and higher resonance frequency in the outer ones. what this will result is that the middle strings will be more bouncy and thus a perception of a small sweetspot and makes the racket less playable.

the solution then, is to lower the tension as you move outwards. the lower tension plus the short length on the outer string segments will produce similar resonance frequency and thus increases the sweet spot. and that's what you felt with Mr. Ng's stringing, in which i also agree is excellent.

i have done similar experiments. try stringing a racket with uniform tension throughout and then tap on the middle and outer strings, note the difference in resonance frequency, and then string a racket with lowering tension, and also note the resonance frequency. then take the rackets to the court and see which one plays better....

so if my theory is correct, the goal that you want to achieve is to be able to vary the tension in such a way that if you pluck the strings from middle to outer, you should hear the same tone. and that should be give the optimal playability. try it!

perhaps somebody smarter and more mathematical inclined... say.. BRL can verify if my theory make sense.....

some thoughts concerning the experiments ... consider that my thoughts are just from results of me doing some beginner home stringing... ;) ..

after reading some positive posts about progressive stringing on this forum, i strung some rackets the way Kwun described, lowering tension moving outwards.
but even when i lower the tension of the mains from 27 to 20 lbs, the tone you hear while plucking the string from middle to outer is still higher on the outer strings. the difference is definitely a lot less compared to an 'even' job done by me, but some difference in tone just remains. it may be a result of bad stringing techniques, i don't know. But i don't dare to try 27 to less than 20 because i'm afraid that too much difference in tension will cause unwanted stress on the frame.
One thing i can think of is that from the moment the strings are clamped off at a lower tension than the initial tension, the tension of the already done strings already evens-out... so a 27-20 job in this perspective might results in 25-20 or something like that .. well this is all pure hypothetical.

Sure thing is that i like the bouncy-feeling results of a progressive stringbed much more than that of an even stringbed.

btw i talked to an experienced stringer, and he described another method to 'devide' the tension : instead of lowering tension while stringing, tension is 'transferred' from outer to middle strings, after the mains are knotted, by plucking / pulling up the string next to the middle string, than pulling up the next string to the outer side and so on.

Nah... i'm not a math person... i'm more of a thoery person. Whenever i try to calculate something... i always end up with extra minus signs or misplaced decimals everywhere, and finding the mistakes take forever :mad: :mad: !!

I was thinking the along the same lines as you. The reason we like higher tensions (or at least i do) is because the hits are more consistent with the movement of my racquet and less dependent upon where I hit on the racquet.

Well here's my view wrt physics... i'm sure if i'm applying the right principles or not.. just my first thoughts:

the tension felt by the string is dependent upon the distance of the string from the point of contact with the head of the shuttle to the frame of the racquet. the amount of energy and momentum transfer is invesely proportional to the tension at that point. Thus the repulsive force is double at the centre compared with at the the point between the middle at the frame. The repulsive right at the edge of the frame is zero.

The actual force on the bird is the foece of the racquet movement plus the repulsive force of the strings. So to increase consistency, you have to reduce the randomness from the repulsive force. You can do this by either reduce the magnitude of the repulsive force by increasing tensions at a cost of less power, increasing the repulsive power at the edge of the racquet, or a combination of the two.

.._____
/1.......2\
|............|
|3........4|
|............|
\5.......6/
...~~~~
.....||
.....||


Suppose proportionate strining is used such that it is 28lb at the centre and 24lb at the corners. That's at 20% difference. At the corners (1,2,5,6) the repulsion difference from the centre would normally be around 1/8th, but because of 20% x 2 tension difference, the repulsion difference is changed to around 1/5th, which is like going from 18lb to 30lb. That's pretty good! The effect is halved at 3 and 4 though.

Yong,

so you have been using the progressive tension method. no wonder your smashes are so hard, i was all over the floor. i don't believe you used something i taught you against me.. ;)

anyhow. the theory i have listed still needs to be refined. there are some inconsistencies and parts that doesn't make that much sense. if you have measured the length of strings, the very outer main string is almost 1/2 the length of the middle main string. in order to get them to be the same frequency, the tension need to be halved, ie. 13.5lbs in your case. that is certainly a very big difference and since the string is a single piece of string afterall, the string will slide and evens out as you have mentioned. aside from that, i think the relation between response and frequency is not as linear as i have described.

but certainly we are on the right path i think....

BRL,

interesting theory. i will take time and digest it and will post my comment later. i am at work. gotta finish this darn program by the end of the day. ugh.

btw, i am also a theory guy. ;)

Originally posted by kwun

anyhow. the theory i have listed still needs to be refined. there are some inconsistencies and parts that doesn't make that much sense. if you have measured the length of strings, the very outer main string is almost 1/2 the length of the middle main string. in order to get them to be the same frequency, the tension need to be halved, ie. 13.5lbs in your case. that is certainly a very big difference and since the string is a single piece of string afterall, the string will slide and evens out as you have mentioned. aside from that, i think the relation between response and frequency is not as linear as i have described.

but certainly we are on the right path i think....



Also you're neglecting edge effects. Given that a lot of the repulsion of the strings come from support from the bed of strings around the impact point. Say hypothetically your smash means that the cork comes into contact with a total of 3 cross and 3 main strings. The strings next to these whilst not being in contact with the cork will also move in response. Just looking at the main if the centre point moves 5 mm, the cross next to it (that isn't in contact with the cork) also has to move.

Okay now that's obviously common sense and in the centre of the strings that works. However as at the edges of the string bed near the frame, to things happen. The gap between the strings and the frame tends to be larger at most times, and the frame is for purpose of this exercise is incompressible (unless you're using a TI SP ;P). In real terms you'd probably need to get 3 or 4 strings from the frame to be able to ignore these effects (which admittedly is where you should be hitting anyway). However as to what th ideal tension of strings should be near the frame, well that gets complicated.

I believe that the evening out of the tension is probably a major feature too. Hypothetically you could start with the highest tension in the centre of the racquet the lowering as it reaches the sides, but as the stringing gets older, the tension will even out, negating the effect (unless you knot every string ;P).

Evening out of tension will depend on the friction of the strings on the grommets. Actually, we can test that out by marking the grommet area of a freshly strung racquet with a marker pen and then checking the position after a few games.

Originally posted by Cheung
Evening out of tension will depend on the friction of the strings on the grommets. Actually, we can test that out by marking the grommet area of a freshly strung racquet with a marker pen and then checking the position after a few games.

Yes we could do this however it's a fair assumption that say if you hit to the side of your racquet where you have lowered the tension, the strings will move slightly to that side and the tension between that string and the higher tension string next to it will even out slightly, but won't return.

Hypothetically if we have perfectly even string tension then the strings shouldn't move nearly as much? Actually let's say you hit at exactly the same spot every time, then those strings you hit with should be slightly higher tension than the others given that grommet friction will mean that the strings won't completely return back into position. Unfortunately this falls down because of frayed strings, on one of my TI SPs before it got broken I had one frayed string, right in the dead centre of the racquet, it looked really cool like I only hit on one spot with every shot ;P

G'day,

Loooong time since I've been here so I'm kinda out of touch with what's been happening...!

I've been doing progressive string technique since late last year and although I have no scientific background to back my claims up, I do have 2 identical rackets strung at same tension, same string but with different techniques.

Without getting into the boring details, the progressively strung racket was a lot better in every respect and much more user friendly. This stringing technique in my opinion improve power but definately increase control with larger sweet spot. Even at highish tensions it didn't need the "break-in" period needed, comparing to rackets strung at constant tension.

And it is less scary to string Iso rackets at high tension as the frame suffers from less distortion.

I can go on and on but I'll shut up and if anyone care to find out the difference just let me know and try my rackets out. ;)

The racquet will sure look darn ugly but maybe we should give it a try and knot every string!!! :D For Iso racquets, one could just knot the central 8 main strings and knot every other string.

Originally posted by Pecheur

I believe that the evening out of the tension is probably a major feature too. Hypothetically you could start with the highest tension in the centre of the racquet the lowering as it reaches the sides, but as the stringing gets older, the tension will even out, negating the effect (unless you knot every string ;P).

Does anyone know anybody in the Greater Vancouver Area that does this kind of stringing? I need to restring my rackets, so i figured i can try this kind of stringing technique.

Hi Grufey,

Badrad used to do progressive stringing method but he no longer bothered to. So, I guess you have to go to HK and ask Mr. Ng of Luxis to do it for you ;) .

Do you experts think it is worth the trouble to do progressive stringing between 21 - 24 lbs?

Originally posted by Pete LSD
Hi Grufey,

Badrad used to do progressive stringing method but he no longer bothered to. So, I guess you have to go to HK and ask Mr. Ng of Luxis to do it for you ;) .

you could pay Badrad a bit more to do it for you. I think it would be cheaper (and maybe safer) than coming to HK.:rolleyes:

This is from Laurence:

MP-100 JP (27 lbs string job from Luxis)

Central 8 main strings, 27 lbs
Outer main strings, 24 lbs

Central 1 cross string, 23 lbs
Outer cross strings, 21 lbs

____________________________________________

What about a 30 lbs string job? Mr. Ng told me he had to modify his usual string job technique the first time I asked him to string 30 lbs for me. BTW, Mr. Ng usually string 26 - 28 lbs.

Here is my guess of what Mr. Ng did but I maybe wrong:

Central 4 main strings, 30 lbs
Next 2 main strings away from the central 4 main strings, 28 lbs
Outer main strings, 24 - 25 lbs

Central 1 cross string, 26 - 27 lbs
Outer cross strings, 24 - 25 lbs

Any opinion from the expert is highly appreciated. Runner23, Yong, Kwun, and others . . . please chip in with ideas :) . Thanks.

Originally posted by Pete LSD
Do you experts think it is worth the trouble to do progressive stringing between 21 - 24 lbs?
why don't u ask mr. ng?

Simple, I have to make a long-distance call. ;)

Originally posted by cooler
why don't u ask mr. ng?

Originally posted by Pete LSD
Simple, I have to make a long-distance call. ;)

but u will get the correct answer from an authorative source

In that case, you might consider chipping in the long-distance charge. :D

Woah.....

I've been stringing my racket strings progressively from highest tension (starting centre and move outwards) downwards, (ie - 27lbs, 26.5, 26lbs etc) trying to ensure all strings have the same tension thruout the string bed - for both main and cross - does this mean I am doing it all wrong?

The racket plays well but with nice big sweet spot....so I can't be that wrong...I hope! :(

Ayl,

So you decrease lbs by 0.5 as you move from centre mains and crosses?

Do you lower the lbs on the cross by 10% compared to the mains?

[QUOTE]Originally posted by Pete LSD
[B]This is from Laurence:

MP-100 JP (27 lbs string job from Luxis)

Central 8 main strings, 27 lbs
Outer main strings, 24 lbs

Central 1 cross string, 23 lbs
Outer cross strings, 21 lbs

____________________________________________
So, they string the main with higher tension than the cross?

G'day Peter LSD,

I don't actually reduce tension by 0.5lbs progressively as per say. I actually vary the tension proportionally based on the distance of string between frame, so depending on the racket, it may drop gradually and then significantly, especially on a Iso racket as I pass the 2-10 O'clock position. I had to calibrate my drop weight many times to get this right but I must admit that my string technique is still does not produce 100% equal tension thruout.

The last racket I did, the Cab20, must have been pretty close to being strung to
"perfect" tension, as it had a great lively feeling to it comparing to Cab21, strung with same tension but with slight error on the cross stringing. The Cab21 had a much smaller sweet spot.

Yes and I do reduce tension by 10% on cross strings. Sometimes I think I reduce it even more.....still learning! ;)

Hi ayl, does your racket retain the same shape after the string work? I usually put 2 more pounds on the cross to retain the original shape of the cab racket. I was believing that this is common for stringing cab racket.

Good idea Cheung, that marker test.
Well, i like experiments, so i just finished stringing my racket using progressive stringing method again and i also marked the strings. No i wasn't so overenthousiastic that i cut the strings first.
Kwun was returning my smashes all the time, so at the end the strings gave up and broke :)
Interesting tension data BTW, Pete, but i'm a bit surprised about the big difference between main and cross. In a former thread, it was said that Luxis does use some kind of side support on their new Yonex machine, so that might be te reason why cross tension is lower than main tension.
For this test (6 point machine) i used the following tension :
Main : 27 lbs for middle 6, 24 for next 2 strings, 21 for next 2 strings and 18 on the outer stings
Cross : 21 for outer 4 strings, 22 next 2 stings, 24 for middle 10 strings, then lowering to 21 again.
I marked the main strings right after stringing 2 or 3 of them and the first observation that can be made is that the markings didn't shift throughout the stringing process.
I marked the cross strings after stringing them all.
Stringbed is feeling ok, lets see if the markings shift after some playing. Ah, Friday will be my first playing opportunity :(
Oh yes, i forgot : plucking the main strings resulted in a pretty constant tone !

Yes, Mr. Ng does own a four point stringing machine. However, when I asked him if he lowered the cross tension he said he had to follow Yonex's recommendation of adding 2 lbs to cross.

Thanks for the data Yong. I can imagine the progressive technique takes longer to finish given the varying lbs.

Originally posted by Yong
Good idea Cheung, that marker test.
Well, i like experiments, so i just finished stringing my racket using progressive stringing method again and i also marked the strings. No i wasn't so overenthousiastic that i cut the strings first.
Kwun was returning my smashes all the time, so at the end the strings gave up and broke :)
Interesting tension data BTW, Pete, but i'm a bit surprised about the big difference between main and cross. In a former thread, it was said that Luxis does use some kind of side support on their new Yonex machine, so that might be te reason why cross tension is lower than main tension.
For this test (6 point machine) i used the following tension :
Main : 27 lbs for middle 6, 24 for next 2 strings, 21 for next 2 strings and 18 on the outer stings
Cross : 21 for outer 4 strings, 22 next 2 stings, 24 for middle 10 strings, then lowering to 21 again.
I marked the main strings right after stringing 2 or 3 of them and the first observation that can be made is that the markings didn't shift throughout the stringing process.
I marked the cross strings after stringing them all.
Stringbed is feeling ok, lets see if the markings shift after some playing. Ah, Friday will be my first playing opportunity :(
Oh yes, i forgot : plucking the main strings resulted in a pretty constant tone !

Yong, going off topic a bit. Are you using a crank or a drop weight machine?

Pete, it's a Crank machine.. the knob at the end of the tensioner is very comfortable to lower the tension for this kind of progressive stringing.

Sorry to interrupt, according to my knowledge, the so-call "progressive high-tension stringing" is a tricky way to raise the stringing tension when you're using a 2 point/no protection system (old style) stringing machine. It's a "fake" high tension stringing method and is not accepted by the pros, since the "high tension" last not that long.

Some stringer, in the past, want to increase the tension, but they're only using an old style, no protection machine, so they'll add a few more pounds at the center of the racket(mains & crosses), to make the string bed stronger but not to break the racket when stringing in full over-tension method. This is a method of stringing in the market and i know, even for some players of the HK team (since HKSI is using a no protection stringing machine.)

It makes no harm to your racket and it's a good way to raise the tension a bit, but when we're stringing for the pros, even for 10 years ago, we're using the 6 points protection machine and stringing at Full over-tension up to 32 pounds.

Discussion are welcome, since we'd like to know, how the other stringer "tells" you the history or benefits of this type of stringing method. But according to our experience, this is not a good way to string a racket - the tension won't last too long and will add extra stress to the corners of the rackets.

Correct me if i'm wrong.

We've been stringing for every Five-stars, Grand Prix, Thomas/Uber Cup finals held in Hong Kong for the past 16 years.

Lok, you are correct to say that progressive stringing method does not give true tension wanted by the player. However, the playability of the racquet is substantially improved.

Originally posted by OT23 Lok
Sorry to interrupt, according to my knowledge, the so-call "progressive high-tension stringing" is a tricky way to raise the stringing tension when you're using a 2 point/no protection system (old style) stringing machine. It's a "fake" high tension stringing method and is not accepted by the pros, since the "high tension" last not that long.

Some stringer, in the past, want to increase the tension, but they're only using an old style, no protection machine, so they'll add a few more pounds at the center of the racket(mains & crosses), to make the string bed stronger but not to break the racket when stringing in full over-tension method. This is a method of stringing in the market and i know, even for some players of the HK team (since HKSI is using a no protection stringing machine.)

It makes no harm to your racket and it's a good way to raise the tension a bit, but when we're stringing for the pros, even for 10 years ago, we're using the 6 points protection machine and stringing at Full over-tension up to 32 pounds.

Discussion are welcome, since we'd like to know, how the other stringer "tells" you the history or benefits of this type of stringing method. But according to our experience, this is not a good way to string a racket - the tension won't last too long and will add extra stress to the corners of the rackets.

Correct me if i'm wrong.

We've been stringing for every Five-stars, Grand Prix, Thomas/Uber Cup finals held in Hong Kong for the past 16 years.

But what i think it's more of psychological than physical...

Maybe what we need is to use lower tension on the whole rahter than using that method? say 23lbs?In our believe and experience, most of the club players, are satisfy with our 23-24 lbs.

What i want to tell is, using your method will add extra stress to the corner of the frame and will shorten the life of the racket. Besides, the tension isn't the "tension", don't you find that?

but anyway, it's fun to "learn" more here.

Lok,

did you read further up the thread in a post i made. it talks about how the response of the string near the side and the center of the frame are different and that progressive stringing is there to cancel out the difference and gives a uniform response and also larger sweet spot.

and then further down the thread, another poster did an experiment with stringing a racket both ways, progressive and non-progressive and found more positive feel on the progressive method.

what're your thoughts on that?

perhaps another experiment one can try is to string 3 rackets, one high tension uniform, one high tension progressive, and one low tension uniform and compare the 3. that will be the most scientific experiment.

Originally posted by OT23 Lok
but anyway, it's fun to "learn" more here.

i agree! and it is nice to have a seasoned stringer like you contributing to the discussions. hope to see you more here. :)

I tried 28 lbs X 28 lbs before. Trust me, it's not as playable as 28 lbs strung progressively (incrementally).

Whether the progressive method adds extra stress to the corner of the racquets is not my area of expertise. None of my racquets strung by Mr. Ng have suffered any frame failure as a result of progressive stringing method used. Also, lbs/unit length is kept more or less constant.

Originally posted by OT23 Lok
It's a "fake" high tension stringing method and is not accepted by the pros, since the "high tension" last not that long.

. . .

But what i think it's more of psychological than physical...

Maybe what we need is to use lower tension on the whole rahter than using that method? say 23lbs?In our believe and experience, most of the club players, are satisfy with our 23-24 lbs.


I get the impression that you are suggesting the progressive strining method feels better because it is "truly" at a lower tension, and that the club players would recieve the same benefit from using a lower tension.

From the impression I got from other players, it seems that they are strining their racquet at the centre at a higher tension while keeping the sides at their "old" tension. If my presumptions are true, then your explanation does not fully explain the observations from these players.

As kwun points out, i think the benefit comes mainly from redistributing the tension such that it is highest at the sweetspot and lowest elsewhere.

i have to agreed more on OT23 Lok's point of view than pro progressive user. It was useful in the olden days of wooden racquet and thick strings. However, i dun see much benefit of its use in today's equipments. Depending the differential tension spread, it could add unnecessary stress to the racquet's corners. I only tried once on my racket and never used on my client racquets. It is pseudo way to jack up tension on old or weak racquet. The effect only last temporary.

peter, your 28x28 is not as playable as Progressive strung 28 becasue u can't handle true 28 lbs. A progressive 28 is not a true 28 pounder, it average out around 25-26 lbs, depending how low of a tension at the edge. Also, in most cases, it is placebo effect as well.

However, progressive tension has its use in unique case and application.

Originally posted by kwun
to have a good and "uniform" string bed with a big sweet spot, one need to string the racket in such a way that across the string bed, all the individual string segments have similar response.

my theory so far, is that the tension itself is not the main determining factor to the playability of the string. instead, i believe the natural response of the string, kinda like "bounciness" is the determining factor. i skipped the mech engineering class on resonance when in college, but i believe that the natural resonance frequency of the string determines the natural response. (actually, more accurately, the natural response of the string determines the natural resonance frequency via a second order differential equation)

as the racket is more of an oval shape and not square, to string all string segments in equal tension but varying length will produce lower resonance frequency in the middle string and higher resonance frequency in the outer ones. what this will result is that the middle strings will be more bouncy and thus a perception of a small sweetspot and makes the racket less playable.

the solution then, is to lower the tension as you move outwards. the lower tension plus the short length on the outer string segments will produce similar resonance frequency and thus increases the sweet spot. and that's what you felt with Mr. Ng's stringing, in which i also agree is excellent.

i have done similar experiments. try stringing a racket with uniform tension throughout and then tap on the middle and outer strings, note the difference in resonance frequency, and then string a racket with lowering tension, and also note the resonance frequency. then take the rackets to the court and see which one plays better....



OT23Lok.

Kwun's theory has some scientific basis to it. I've underlined the very important scientific principle that is the basis of the claimed improved playability. I personally have no opinion on the method. So long as the string is tight enough in the middle of the racquet, I don't really mind how the racquet is strung (so long as it doesn't break).

Actually, for you other guys, somewhere in the back of mind I do remember somebody else saying progressive stringing was for 2 point stringing machine at high tensions(not on this board) simply not to break the racquet. I can't remember who (and it wasn't Luxis).

Was there some article once in worldbadminton about how a stringer uses progressive tension method for Jens eriksen? I can't find that article now.

Originally posted by cooler
Also, in most cases, it is placebo effect as well.

Originally posted by OTLok23
But what i think it's more of psychological than physical...


ie both Cooler and OTLok23 are stating the same thing....maybe it's all in the mind.:p

Originally posted by Cheung

Was there some article once in worldbadminton about how a stringer uses progressive tension method for Jens eriksen? I can't find that article now.

here:

http://www.badmintonforum.com/vb/showthread.php?s=&threadid=371


got this from badmintonasia, interviewing one of the stringers for the Danish team:

"How long does it take to string a racket ? " Normally, it would take
me around 20 minutes each, but some players want such a high
weight that it can take over 90 minutes. For instance, Jens Eriksen,
the Danish double player ranked in the top five in the world uses
a weight of 16 kg. But the frame wouldn't hold it so I put the 16
KGs in the Centre of the racket then I have to put on a lower
weight as the strings get closer to the frame. And this takes some
time and "doigté" ""


as you can see, Cheung and I have the burden of having to remember 78000+ posts in this forum.. also the burden or aging.. :)

a few words on low vs. high tension progressive stringing. all the experience i have are at medium tension, around 24-26lbs. i believe progressive stringing have the same effect in both medium and high tensions. with the added benefit at higher tension that controlling uneven stress on the frame is more critical.

so while the subject of the thread is for high tension, my analysis has been for all tensions and i believe progressive stringing applies to both.

i want to add a few more words on stress on frame in progressive vs. uniform stringing methods.

Lok claims (and later cooler agreed that) progressive stringing induces extra stress on the frame. after some thoughts, i beg to differ. in fact, i will claim that, comparatively, uniform stringing produces more stress on frame. in other words, progressive stringing decreases the stress.

here is how i arrived at that conclusion.

firstly, i hope we all agree that "stress" on racket frame is induced by non-uniform tension on the racket frame, eg. if at one location the string is pulling at high force/tension, while in other locations, the force/tension is lower.

on first look, progressive can lead to higher stress. afterall, by definition, we want to string the racket with varying tension. however, we should first look at the diagram attached. this illustrate a string bed with uniform stringing tension, without loss of generality, let's assume we are stringing at 25lbs. so by definition of uniform stringing, all string segments are pulling on the racket frame with 25lbs worth of force.

ok, so at the top of the frame, where there are one only string per hole, we see that the strings are pulling on the frame with force of:

25lb x sine(theta)

where theta is the angle between the string and the frame. and most of the time, theta is pretty close to 90degrees. so sine(theta) is pretty close to 1. this is the same for the side of the frame.

however, let's look at the corner of the frame, where we have two strings pulling on the frame at approx 45 degree. by vector addition, we find that the total force acting on the frame is now :

25 lbs x sine (45) + 25lbs x sine (45)

which comes to around 35 lbs!

on other words, with uniform stringing method, we actually have a non-uniform pull on the frame and thus produces extra stress on the racket frame.

not sure if you have seen this, but i have seen it on many racket, esp cab rackets. after stringing at high tension of 25+ lbs, we find the the corners of the rackets get squeezed in. and now i believe this is exactly the reason, that uniform stringing is pulling on the racket frame non-uniformly.

if you have followed my argument this far, then i think you can probably deduce the rest. with progressive stringing, we are actually lowering the tension as we move towards the corner of the racket, cancelling out the 2 x sine(45) extra force acting on the racket. as a result, there is now less stress on the racket frame.

i hope this makes sense.

Cooler, I can handle 28 X 28 and all the way to 30 X 30. I am just saying the progressive method gives one a better feeling.

Originally posted by cooler
i have to agreed more on OT23 Lok's point of view than pro progressive user. It was useful in the olden days of wooden racquet and thick strings. However, i dun see much benefit of its use in today's equipments. Depending the differential tension spread, it could add unnecessary stress to the racquet's corners. I only tried once on my racket and never used on my client racquets. It is pseudo way to jack up tension on old or weak racquet. The effect only last temporary.

peter, your 28x28 is not as playable as Progressive strung 28 becasue u can't handle true 28 lbs. A progressive 28 is not a true 28 pounder, it average out around 25-26 lbs, depending how low of a tension at the edge. Also, in most cases, it is placebo effect as well.

However, progressive tension has its use in unique case and application.

I'm new to this progressive stringing, what are the benefits and do you use 2 knots or 4 knots?

Originally posted by kwun
firstly, i hope we all agree that "stress" on racket frame is induced by non-uniform tension on the racket frame, eg. if at one location the string is pulling at high force/tension, while in other locations, the force/tension is lower.

sorry i can't agree with the words you used, though i do agree with what i think you are trying to say. I'd say that stress on a racquet frame is caused by the application of a net force on a specific area of the racquet. Using this definition, the progrssive strining method will appear to be less stressful right off the bat.

Using this definition, your trigonometry calculations of tensions will be slightly different. changing 25 by 25 to 35 would be oversimilifying since the two strings are not joined. because they are at right angles to each other, it is like the racquet is being pulled apart at that point, rather than being pulled downward. One can argue that the racquet is suffering from 50 lb of tension at that point. replacing that setup with a single string at 35lb in the direction you indicated would be much more friendly to the frame. Thus, an increase in tension will be amplified more so than you suggest. This means a progressive strining method will be even less harmful to the friend than you suggest.

Originally posted by ants
I'm new to this progressive stringing, what are the benefits
we are debating this right now actually. :p :D

I have to say that I agree with Lok and Cooler. Unless you tie the main strings off after stringing at that high tension, the strings will stretch and eventually settle on an optimal tension. So even if you string your first 8 main strings at x lbs and lower the others as you go along. After tieing off the mains, the string will eventually settle to an optimal tension y where y will be less than x so in effect, you are playing with a lower tension and hence a bigger sweet spot (the playability factor) than one that is truly strung at x lbs.

As for different stress on the racquet frame, remember that arches are stronger than straight beams.

Originally posted by Winex West Can
I have to say that I agree with Lok and Cooler. Unless you tie the main strings off after stringing at that high tension, the strings will stretch and eventually settle on an optimal tension. So even if you string your first 8 main strings at x lbs and lower the others as you go along. After tieing off the mains, the string will eventually settle to an optimal tension y where y will be less than x so in effect, you are playing with a lower tension and hence a bigger sweet spot (the playability factor) than one that is truly strung at x lbs.

As for different stress on the racquet frame, remember that arches are stronger than straight beams.
I dont think anyone is denying what you just said. What some have said however is that a racquet using progressive strining will have a bigger sweespot than a traditionally strung racquet even at the same average tension. I do share your sceptism about how long the differential tensions last.

hahaha, it's really funny to discuss with you guys here, very scientific!

but what i want to tell is i totally agree with Winex west can, and that's what i think!

We haven't carry out any scientific experiments nor tests, but we string 5000+ rackets every year for almost 20 years and most of our customer are satisfy, i think i can convince myself that we're using the right method for our clients and the pros.

My last word, No matter what stringing method we use, we all want to make the user play better games, right? :)


Happy Games!

*sigh* unfortunately, life is not black and white.
There are cases where PT (progressive tension) give the desired benefits, depending what kind of benefit the user want it to be. The agrument presented by kwun is very convincing but that is for initial condition. If one string it perfectly using PT, that's great initially. However, when the strings start to equalizing their tension over time, the stress get re-distributed, hence, re-shaping the frame shape, although too small for the eyes to notice as frame shape changes progressively. Overall tho, a 28x28 racket will alway be more stressful than a 28 PT because on average, PT at 28 is not really 28 but average out around 24-25 lb, assuming the edge tension was initially 20 lb.

kwun, for those cases u mention that most racket u saw having distorted sides. True but i think that has to do with poor stringing technique. Most stringers follow top down for cross so the top half get squeezed. I don't follow the so call yonex prescribed method so i don't have those problem.

To sum things up, i think there is benefit of PT stringing but only in unique situation and the benefit is temporary (if one use modern racket and string) . Maintaining and controlling the racket shape during stringing is much more important in minimizing stress and strain on the frame. If anyone restring their racquet as frequently as pros, then go for PT.

WWC has a point that over time, the "progressiveness" of the progressive stringing will average out. but i also argue that it will take time as there is sizeable amount of friction in the grommet to restrict movements.

and in between the initial stringing and the weeks after that, the player will still experience from the benefit of progressive stringing.

Originally posted by bigredlemon
sorry i can't agree with the words you used, though i do agree with what i think you are trying to say. I'd say that stress on a racquet frame is caused by the application of a net force on a specific area of the racquet. Using this definition, the progrssive strining method will appear to be less stressful right off the bat.

Using this definition, your trigonometry calculations of tensions will be slightly different. changing 25 by 25 to 35 would be oversimilifying since the two strings are not joined. because they are at right angles to each other, it is like the racquet is being pulled apart at that point, rather than being pulled downward. One can argue that the racquet is suffering from 50 lb of tension at that point. replacing that setup with a single string at 35lb in the direction you indicated would be much more friendly to the frame. Thus, an increase in tension will be amplified more so than you suggest. This means a progressive strining method will be even less harmful to the friend than you suggest.

BRL,

i think we have different definition of "stress" here. i think your definition of stress is just "force". ie. the less force, the less stress. that's more align with the scientific term of stress, as in stress and strain.

however, i believe the definition we have been using is more of a differential stress, meaning, the material internal stress presence when different part of the frame is experiencing different force, causing internal "stress". the different in force in different part of the frame cause bending and shear of the frame, and if there is enough of a difference over a prolong amount of time, the frame will give in and crack.

the stress that i have pointed out then, is the difference between the 25lb on the top of the frame, and the 35lb *net* force on the corner of the frame. the 35lbs will pull the frame in more than the 25lb, and creates internal stress on the frame and as i have seen in some cases, bends the racket frame out of shape.

Originally posted by OT23 Lok
My last word, No matter what stringing method we use, we all want to make the user play better games, right? :)

Happy Games!

As you have discovered, BF can be very scientific! Always so much theory but frustratingly, many things we cannot prove or disprove. Most of the time, we do not have access to the right scientific data.

Kwun, good explanations on the tangential forces at the corners. I have put markings on the string and see if it will shift in time. Stretching and shifting exist in all stringing methods. I always find the center strings lose its tension after playing for a few times. This is much more noticeable in uniform tension string bed. I believe uniform tension string bed will become progressive tension ( in an unfavorable way ) in time. PT should have its advantage in long term performance.

i was searching for some related patents last night, and i found this in a US Patent (6,179,735). the patent is about how to use little stoppers to stop the strings from sliding. the motivation, of course, is exactly what we are talking about here, is to achieve differential tension (or as we call it here, progressive tension) and not have the strings sliding around the grommet.

--------------------------------------------

Currently available sporting racquets, for example tennis racquets, are continuously strung by passing a length of stringing material through holes in a frame, pulling the length of stringing material to a predetermined pressure and tying it off under pressure against itself. The pressure is retained within the length of stringing material. Conventionally, a single length of stringing material forms strings which run length-wise in the racquet head and a separate single length of stringing material forms strings which run cross-wise.

Because of this stringing method, the tension of each string in the racquet (the term "string" being used herein to mean one string "span" from one side of the racquet head to the other, and not the total length of stringing material) is substantially similar across the entire racquet face (the term "racquet face" being used herein to mean the strung area of the racquet head) . The "elastic quality" of a tensioned string depends upon the tension applied and the length of the string. The amount of "elastic bend back" experienced by a relatively long string in a conventional racquet head when an object is struck will be greater than that available to the shorter strings in the racquet because all the strings are at substantially similar tension i.e., the elastic properties vary in dependence on the length of the string. This can have a deleterious effect on shot playing. For example, it is well known that in tennis it is desirable to strike the ball at the centre area of the racquet face, to ensure that the ball travels in the desired direction with the desired power. At the centre area of the face of a conventionally strung tennis racquet the strings will have similar elastic properties, by virtue of the fact that the length differences between strings are at a minimum. This centre area is generally known as the "sweet spot".

At the outer area of the racquet face the shorter and longer strings will have different elastic properties. It is well known that control and power applied by the outer area of the racquet face of a conventional tennis racquet is extremely unreliable. Hence the desirability of striking a ball with the centre of the racquet face.

Even towards the centre of the racquet face in the so-called "sweet spot", the elastic properties of the strings vary somewhat.

In presently available sporting racquets, therefore, a perfect sweet spot does not exist and the nearest approximation to a sweet spot is located in a small area, generally towards the centre of the racquet face.

more good stuff:

--------------------------------------

From a first aspect, the present invention provides a method of stringing a racquet, comprising the steps of independently tensioning at least a plurality of strings in the racquet and applying means for maintaining the independent tensioning.

By "independently tensioning" is meant the application of tension independently to each string of at least the plurality of strings.

The plurality of strings are preferably independently tensioned to different tensions (differentially tensioning) and the resultant differential pressures between strings maintained.

Preferably, all strings in the racquet will be independently tensioned, although embodiments are envisaged where some of the strings may be strung by prior art methods and the others independently tensioned.

In at least preferred embodiments, the ability to independently tension strings to different tensions and maintain the resultant differential pressures between strings can result in vast improvements in racquet quality. It is possible to provide a racquet face where the elastic quality is substantially even over the entire face. In other words, it is possible to provide a racquet which has a "sweet spot" across substantially the entire racquet face.

The ability to individually control tension also allows "zoning" of the racquet face. Different areas of the racquet face may display different qualities.

It is also possible to use different gauge and/or material strings in different areas of the racquet face to assist variation or provide further variation in racquet characteristics.

A "sweet spot" over the entire area of a racquet will generally be achieved by having the tension in the longest strings the greatest, stepping down the tension for shorter strings. For example, where the tension in the longest strings (the base tension) is 28 kg, then the tension in the shorter strings is set lower, say 26, 24, 22, 18 etc., depending upon their relative length with respect to the length of the longest string. We have found that stepping down, or providing differential tensions between the strings in this manner provides the best method of obtaining even elastic quality over the entire surface of the racquet.

Kwun,

well done! The part in bold is a key to our argument.

Now all we have to do is find out is do the strings move.

I asked somebody else about progressive stringing method. He said 'only the cross, not the mains'. However, since we were concentrating on other things, we didn't carry it on further.

Originally posted by kwun
where the tension in the longest strings (the base tension) is 28 kg, then the tension in the shorter strings is set lower, say 26, 24, 22, 18 etc., depending upon their relative length with respect to the length of the longest string.

This should be in application to tennis racquets.

Presuming we can account for diameter of string and length can we extrapolate this to a badminton racquet. There seems to be no obvious reason why not.

There must be some sort of equation we can use to provide an optimal size sweet spot in a badminton racquet using progressive tension stringing. However, if the differential tensions are small, then we could say progressive tension stringing might have a negligable effect.

This equation would be different for different racquet head shapes, iso, oval, tear shapes.

What's stopping us from inserting a "mini-cork" into the grommets to stop the string from sliding? Also, doesn't this mean that MP frames are the worset-suited for progressive stringing?

Originally posted by Cheung

Now all we have to do is find out is do the strings move.

I asked somebody else about progressive stringing method. He said 'only the cross, not the mains'. However, since we were concentrating on other things, we didn't carry it on further.

yes. waiting for results from those who are doing experiments!

another factor is string stretching. the center strings are hit more often and those are more likely to stretch and lose tension.

as for main vs. cross. i don't know. but i'd think it affects the mains as much if not more than the cross.

Originally posted by Cheung
There must be some sort of equation we can use to provide an optimal size sweet spot in a badminton racquet using progressive tension stringing. However, if the differential tensions are small, then we could say progressive tension stringing might have a negligable effect.



yes, in fact the patent go into some equation, but the formula looks more like the result from trial and error than derived.

i haven't digested that part of the patent yet. will post that later.

Originally posted by bigredlemon
Also, doesn't this mean that MP frames are the worst-suited for progressive stringing?

Seems likely

Originally posted by bigredlemon
What's stopping us from inserting a "mini-cork" into the grommets to stop the string from sliding? Also, doesn't this mean that MP frames are the worset-suited for progressive stringing?

nothing. in fact, that's what the patent is about. someone invented some funny grommets to stop the strings from moving.

yes. it looks like MP frames are worse for progressive stringing as the muscle bumps encouragess the string to slide around. just another gimmick from Yonex imho.

The Muscle Bumps can have a layer of very rough material, in order to prevent the strings from sliding.

Originally posted by Pete LSD
The Muscle Bumps can have a layer of very rough material, in order to prevent the strings from sliding.

but isnt the whole point of having muscle bumps is to let the strings to slide in order to prevent breakage? They might as well just remove the bumps altogether and use fatter grommets.

Also, having the string slide across rough material (of course the strings will still slide some) will kill the strings pretty quickly. Just stringing a rough string like 88ti can produce frays.. imaging the effects of something more coarse!:eek:

I thought the whole point of having muscle bumps were for the sake of evening out the pressure where the string was in contact with the frame instead of very high pressure at two contact points.

kwun, on the other hand, new trend in tennis racket is roller cam which let strings slide around purposely. The MP bump mimics that as it would be too heavy to have roller cam badminton racket.

but why would we want the strings to slide? I can only thing of one reason: so that the actual tension we feel is higher during delicate shots while lower (more power) for hard hits.

i don't know how much tennis science is applicable to badminton. Remember that tennis saying, low tension = more power.

Regarding roller grommet, i heard about it a year ago but i can't seem to find any info on it now. Maybe it was just a lab experiment and not a commercial technology. Just to clarifying what i've said before.

I just remember, i saw it on the Popular Science magazine under What's New section.

Has anyone tried stringing the center strings seperately? It should minimize the movement from the high tension to the low tension area. This should also save us time and money when replacing the string. If you only replace the 8 main rows in the center, 1 pack of string will last you a few times of restringing and only 5-7 minutes to restring. This makes it more practical to have fresh string every week. ( If you have your own stringing machine ) Also the 8 mains can be strung with 2 pieces of string. 1 piece stringing the odd rows and 1 stringing the even rows. So, when 1 piece of the string is broken you still have the other piece of string to hold the racket in shape.

Originally posted by Pre-emptive
Has anyone tried stringing the center strings seperately? It should minimize the movement from the high tension to the low tension area. This should also save us time and money when replacing the string. If you only replace the 8 main rows in the center, 1 pack of string will last you a few times of restringing and only 5-7 minutes to restring. This makes it more practical to have fresh string every week. ( If you have your own stringing machine ) Also the 8 mains can be strung with 2 pieces of string. 1 piece stringing the odd rows and 1 stringing the even rows. So, when 1 piece of the string is broken you still have the other piece of string to hold the racket in shape.

That sounds like a pretty good idea... we can use 4 strings (8 knots). The top and bottom cross strings could be at a lower tension, while the middle cross string and the main string could be at higher tension.

Originally posted by bigredlemon
but why would we want the strings to slide? I can only thing of one reason: so that the actual tension we feel is higher during delicate shots while lower (more power) for hard hits.
actually if you are stringing the racket at a constant tension, and the string loosens in the center of the racket, the strings from the two extremes of the racket would "slide in" and compensate for the loss of tension. I think that's the whole idea behing the "MP technololy"

Originally posted by bigredlemon
That sounds like a pretty good idea... we can use 4 strings (8 knots). The top and bottom cross strings could be at a lower tension, while the middle cross string and the main string could be at higher tension.
wouldn't you need 6 peices of string for this?
1 for Main mid section
1 for Cross mid section
2 for main outside section
2 for corss outside section

Also, I was thinking, to "increase the tension" maybe some of the strings that run thru the middle of the racket could have 2 strings run through each gormmet instead of one. Because if there's 2 strings that are supporting on every contact point, the force of impact would be obsorbed by 2 strings instead of 1.

Like this chopsticks story I heard way back in life, breaking 1 or 2 chopsticks would be easy, but breaking a whole collection of'em would be hard

Does anyone get wut I'm trying to say?
If anyone does... plz correct me if this thought/method/idealogy is wrong or unimplyable

Originally posted by JChen99
actually if you are stringing the racket at a constant tension, and the string loosens in the center of the racket, the strings from the two extremes of the racket would "slide in" and compensate for the loss of tension. I think that's the whole idea behing the "MP technololy"


wouldn't you need 6 peices of string for this?
1 for Main mid section
1 for Cross mid section
2 for main outside section
2 for corss outside section

Also, I was thinking, to "increase the tension" maybe some of the strings that run thru the middle of the racket could have 2 strings run through each gormmet instead of one. Because if there's 2 strings that are supporting on every contact point, the force of impact would be obsorbed by 2 strings instead of 1.

Like this chopsticks story I heard way back in life, breaking 1 or 2 chopsticks would be easy, but breaking a whole collection of'em would be hard

Does anyone get wut I'm trying to say?
If anyone does... plz correct me if this thought/method/idealogy is wrong or unimplyable

Since main strings dont cover that much width, i think it'd be fine just to use the one string one tension there. Using seperate strings is more important at the cross, hence 2 or 3 strings there.

As for mutiple strings, badminton string is already multifilament (lots of ultra-thin strings twisted together to form a fatter string.) The performance loss from twisting together 2 fat mutifilament strings will be much much worse than using a super thick string. Imagine the difference between bg 66 and factory strings. Amplify that difference 1000% and that's what you'll get.

Originally posted by JChen99
actually if you are stringing the racket at a constant tension, and the string loosens in the center of the racket, the strings from the two extremes of the racket would "slide in" and compensate for the loss of tension. I think that's the whole idea behing the "MP technololy"


wouldn't you need 6 peices of string for this?
1 for Main mid section
1 for Cross mid section
2 for main outside section
2 for corss outside section

Also, I was thinking, to "increase the tension" maybe some of the strings that run thru the middle of the racket could have 2 strings run through each gormmet instead of one. Because if there's 2 strings that are supporting on every contact point, the force of impact would be obsorbed by 2 strings instead of 1.

Like this chopsticks story I heard way back in life, breaking 1 or 2 chopsticks would be easy, but breaking a whole collection of'em would be hard

Does anyone get wut I'm trying to say?
If anyone does... plz correct me if this thought/method/idealogy is wrong or unimplyable

two parallel strings per grommet hole, done that on my cab 20 power. I wrote it on an old post i couldnt find right now. It has its ups and downs

Originally posted by bigredlemon
That sounds like a pretty good idea... we can use 4 strings (8 knots). The top and bottom cross strings could be at a lower tension, while the middle cross string and the main string could be at higher tension.

Never told u guys before but i do this method all the time, on my racquets only.

G'day,

I am not scientifically minded so I can't explain things like Kwun can, but what I can add in here is what I've discovered with string rackets proportionally.

MP rackets vs Ovals:

I've got 3 MP rackets and 3 Cab rackets all strung recently (all 6 rackets at same day!) with BG80 at identical tension. So far I've noticed that all 3 of my MP rackets holds tension better than Cabs. I personally was anticipating the MP bumps would allow tension to drop more than standard grommets but so far they are holding up much better. Yonex manual stated the MP bumps allow more contact surface areas between string, instead of 2 points on grommet - this so far seemed to work in my case. One very interesting discovery is MP100 & 77 held better tension than MP90...I am wondering if this is due to the fact MP100 & 77 has full bumps all around whereas MP90 doesn't.

How much does string slip:

I've marked 1 MP and 1 Cab racket to find out how much slippage takes place as result of proportional stringing. Here's what I can see on them so far:

Main strings: (starting centre out)

centre 4 strings - tiny but noticable amount of slip
next 4 - tiny amount of slip but the slippage increases as we count away from centre
next 2 - significant amount of slip - the marking has almost disappeared into the grommets
last 3 - some degree of slip on all except last string.

Cross strings: (starting centre out)

center 6 strings - significant amount of slip
next 6 strings (towards handle) - small amount of slip which actually decreases as I count closer to handle.
last 3 - no slip at all

6 strings (towards head of racket) very large amount of slip. Some of the markings appeared on the other side of grommet! (on inside the frame)

next 3- small amount of slip, no slip on last string.

I can only conclude that because I tend to hit off centre (towards the head) the string slipped more on the head on both marked rackets. I was surprised to see cross strings shifted more than the mains, as I anticipated the other way around to be true. Maybe this is because the cross strings are subjected to more punshiment as they are shorter. I don't know.

Today, I strung a friend's racket using Yong's technique (see his post in this topic earlier) and found the racket lose tension fast (with all but center strings shifting!) but with a much bigger sweet spot than my technique of progressively reducing tension one by one. I'll string another racket this week using this technique again with higher tension to see how it performs.

Also, I used a racket strung today (a MP99) with slightly lower tension with BG80, but strung by another person with constant tension technique, and it felt like a bat. Comparing to my MP90 the real way to discribe the difference was mine felt much more "forgiving", especially to off centre hits. I guess this is all to do with size of sweetspot here.

Sorry about the long poor post but it is late here and I've had too many beers.... :( I'll shut up now.

Played 2,5 hours with my marked racket (MP-100 with BG80)
It performerd very well, large sweet spot.
Unlike Ayl's experience, there was very litlle shifting.
Main:
Middle 6 strings : not noticeble
Rest of the strings : 3 on both sides show slight shifting (0,5 mm), only noticeble at the top
Cross :
Only bottom 3 strings show slight shifting (2 X 1 mm, 1 X 2 mm)
In my last post, i forgot to mention that the 1 middle cross string was done at 25 lbs.

Originally posted by cooler
Never told u guys before but i do this method all the time, on my racquets only.

give you do this all the time, it's safe to presume you like it. Do tell! :D

ayl & Yong, can you tell us to which direction did the string slip? i want to know if the higher tensioned center strinng pulled in some outter string. or did the hitting of the shuttle stretched the center string and the less often hit outter string pulled in the slack.

Kwun, in my case, the mark shifted down from the top, thus higher tensiond middle part pulling in the outer string.

I totally agree with you. I find the MP-100 holds tension a lot better than MP-90. Is it because the MP-100 has full bumps all around whereas the MP-90 doesn't is unclear?

[QUOTE]Originally posted by ayl
[B]G'day,

I am not scientifically minded so I can't explain things like Kwun can, but what I can add in here is what I've discovered with string rackets proportionally.

MP rackets vs Ovals:

I've got 3 MP rackets and 3 Cab rackets all strung recently (all 6 rackets at same day!) with BG80 at identical tension. So far I've noticed that all 3 of my MP rackets holds tension better than Cabs. I personally was anticipating the MP bumps would allow tension to drop more than standard grommets but so far they are holding up much better. Yonex manual stated the MP bumps allow more contact surface areas between string, instead of 2 points on grommet - this so far seemed to work in my case. One very interesting discovery is MP100 & 77 held better tension than MP90...I am wondering if this is due to the fact MP100 & 77 has full bumps all around whereas MP90 doesn't.

Originally posted by bigredlemon
give you do this all the time, it's safe to presume you like it. Do tell! :D

for my racquets, i will use the word "HYBRID' to describe my stringing. I follow none of the conventional rules because i don't like its simplistic approach, it's like saying one size fits all. There isn't one set way. It's all depend what and how i want that racquet to perform for that particular task or purpose, and also sometimes what strings and length of strings i have on hand. There, I hope that helps you out. ;)

Originally posted by Pete LSD
I think Mr. Ng of Luxis specialize in the art of progressive high-tension stringing. He once stringed my racquets to 30 lbs. The playability was excellent! The string bed was very bouncy even at that high a tension. Compared to my recent experience with constant tension string jobs, the string bed feels dead and my elbow actually hurt a bit and the tension was only 28 lbs X 28 lbs!

That actually fits with the theory that PHTS method eventually gives you a lower tension. The feeling of the 'dead' string bed is the higher tension. A larger sweet spot results from lower tension, hence the bouncy feeling.

i just brought another two rackets to be strung. my two brand new cab20. i have my stringer string them identically: center 6 mains string 25lbs, then remaining goes down 1lb/string. center 8 cross 26lbs, the remaining go down 1lb/string.

i plan to play with only one and leave the other one alone. that will be the control experiment for string shifting. i will tell you guys my findings in a week or two.

Originally posted by kwun
i just brought another two rackets to be strung. my two brand new cab20
kwun, wut was that on the other post about "not going to get any more rackets until u finish breaking ur inventory of 'em?" ;)

Kwun, why centre 6 mains are 25 lbs and the centre 8 cross 26 lbs? Shouldn't one string the cross 10% less than the main?

Originally posted by kwun
i just brought another two rackets to be strung. my two brand new cab20. i have my stringer string them identically: center 6 mains string 25lbs, then remaining goes down 1lb/string. center 8 cross 26lbs, the remaining go down 1lb/string.

i plan to play with only one and leave the other one alone. that will be the control experiment for string shifting. i will tell you guys my findings in a week or two.

pete lsd, kwun knows what he's doing. Beside, there is no right or wrong tensions as long as u don't breaks the racquet and one like the results.

Pete,

explanation on why 2 more lbs on the cross (http://www.badmintonforum.com/vb/showthread.php?s=&threadid=9516)

Originally posted by JChen99
kwun, wut was that on the other post about "not going to get any more rackets until u finish breaking ur inventory of 'em?" ;)

these are not new! i bought them in november when i was in HK, you must have missed my post about me buying 9 of these for me and my friends and completely cleared out one of the store chains there... :)

Originally posted by kwun
these are not new! i bought them in november when i was in HK, you must have missed my post about me buying 9 of these for me and my friends and completely cleared out one of the store chains there... :)
ei? @@" ic... crazy buyers...

Pete,

where did the 10% number come from? i only understand that we need 1-2lbs to compensate for the shape of the racket and my explanation in the thread that cooler posted.

however, my stringer has a very sturdy 6pt machine that will hold the shape pretty well. and i verified with him that he will actually use the clamps. as a result, i am just adding 1 lbs. anyhow, it is just an experiment, we will see how that goes...

either way, if my explanation in the other thread is correct, then the cross should be strung slightly higher than mains. i dont' see why it should be less...

Thank you guys! I didn't read that post. :mad:

Originally posted by kwun
Pete,

where did the 10% number come from? i only understand that we need 1-2lbs to compensate for the shape of the racket and my explanation in the thread that cooler posted.

however, my stringer has a very sturdy 6pt machine that will hold the shape pretty well. and i verified with him that he will actually use the clamps. as a result, i am just adding 1 lbs. anyhow, it is just an experiment, we will see how that goes...

either way, if my explanation in the other thread is correct, then the cross should be strung slightly higher than mains. i dont' see why it should be less...

we all missed this one as well!!

http://www.badmintonforum.com/vb/showthread.php?s=&threadid=8079

Originally posted by Cheung
we all missed this one as well!!

http://www.badmintonforum.com/vb/showthread.php?s=&threadid=8079

i thought this thread is the followup to the thread that you just linked?

may be we should merge the two threads?

also, i like the name proportional stringing much better than progressive stringing. progressive gives the impression of something that increases with an increasing rate. here we are decreasing with some still to be determined rate....

I back the merging of the threads. we'd have to rename te original thread to a more appropriate name

ok done... and renamed thread to "Proportional Stringing Method"

Originally posted by Yong
For this test (6 point machine) i used the following tension :
Main : 27 lbs for middle 6, 24 for next 2 strings, 21 for next 2 strings and 18 on the outer stings
Cross : 21 for outer 4 strings, 22 next 2 stings, 24 for middle 10 strings, then lowering to 21 again.
I marked the main strings right after stringing 2 or 3 of them and the first observation that can be made is that the markings didn't shift throughout the stringing process.
I marked the cross strings after stringing them all.
.
.
.
Played 2,5 hours with my marked racket (MP-100 with BG80)
It performerd very well, large sweet spot.
Unlike Ayl's experience, there was very litlle shifting.
Main:
Middle 6 strings : not noticeble
Rest of the strings : 3 on both sides show slight shifting (0,5 mm), only noticeble at the top
Cross :
Only bottom 3 strings show slight shifting (2 X 1 mm, 1 X 2 mm)
In my last post, i forgot to mention that the 1 middle cross string was done at 25 lbs.

It looks like shifting stopped after the first playing session.
After 3 playing sessions, markings are still on the same spot as they were after the first playing session. Playability is still very good.

Bumped into luxis today and asked him what he strings at using the high tensions

1) first check the racquet is suitable for high tensions
2) mains - middle ten strings at the tension, rest of strings 2 lbs lower
3) cross - middle ten strings 2 lbs higher than mains, reduce by 2lbs for top and bottom.

We didn;t discuss more as there was badminton to be played but I notice that Luxis' pattern of stringing is slightly different.

I think what Mr. Ng told you is more suitable for 21 to 25 lbs. I am guessing anything higher requires modification.

No, I specifically asked him for the situation when he strings at 32lbs;)

I am very surprised to hear that!!! I still think that a racquet's playability would improve further by incrementally decrease the tension as one moves away from the centre main strings. As Kwun said in earlier posts, one should keep the tone of the string bed constant.

well, it seems a couple of people(including yourself) claim better playability - even faced with Mr Ng's definitive answer(I spoke to him personally) on his method you still doubt it.;)

So, why is the 'feel' better?
Possible working hypotheses:
1) the overall string bed tension becomes lower thus a larger sweet spot
2) perhaps different stringing order of stringing pattern
3) placebo effect
4) ?.......anybody else's help

BF'ers being gifted and impartial scientists (!) will know the importance of good, rigorous scientific data. So we can experiment to find equivalent, subjective feel of proportional stringing vs constant method.

THE EXPERIMENT!
First we need many racquets of the same type - not that easy since each model of racquet will have individual variation characteristics between racquets as well.

We need three racquets strung to constant tension with same string batch and coded.
Then we need three racquets strung to a certain tension using proportional method (all strings done in exactly same manner). These are also coded.
All racquets given to perhaps 3 individuals to test play - their subjective 'feel' of the racquet are recorded. These individuals, the person giving them the racquets AND the person recording the data are NOT told which racquet has which stringing method. The beauty of this is that none of the people know which racquet has which tension, thus eliminating potential BIAS in the results. Only at the end will the codebreaker be able to know and thus analyse the results. The formal term for this sort of experiment is a double-blind trial.

To find which tension of proportional method is equivalent to constant method, we would then have to have more groups of three racquets string to different proportional method tensions.

To allow for string stretching, ideally, the test should be done in the minmum time, ie one session.

There is a another method "Dixon's up down method"...aiyaa, I can't be bothered to go into that and bore you guys....:D

wahh, what happened? how come no replies to my proposal?

1) nobody could be bothered to read it
2) read it but couldn't understand it:(
3) read it, understood it, thought it was idiotic and didn't reply:(
4) read it, understood it, thought 'what a crackpot', didn't reply:)
5) speechless because it was so brilliant:cool:

so why didn't you regulars reply?:p :D

I think it is a good idea but problematic given the different "actual" tension you posted. If you use the "actual" tension, then it's problematic because the prop. batch will feel tighter at first. If you intoduce different racquet to different people at different times, that might work better. BUT your margine of error will still be too high since we only have 3 datapoints.

Actually I forgot how you compute that but why not bring in 5 people if at all possible to increase the sample size.

I like the idea but i don't have the resources to pull that off. Kwun seems to have a batch of racquets that large. If he randomly selects which racquet gets what stringing method (flip a coin) then it would work.

Originally posted by Cheung

To find which tension of proportional method is equivalent to constant method, we would then have to have more groups of three racquets string to different proportional method tensions.



Nice test, but i think the above statement is THE key for analyzing the results of the test in the first place.
If we don't have this data, the test could just prove that the testers who
preferred the proportionally strung rackets like lower tension with larger sweetspot.
Plus we have more groups, thus more results.
Hmmm who is volunteering to organize such a test ? :D

Cheung,

scientific. but logistically tough to do. to be really scientific about it, we not only need to have 3 rackets, but 3 identical rackets, all strung differently, all needs to be available at the same time.

we also need to have more than one data point, ideally, whoever performs the experiment needs to give those rackets to many people (at least 10, if not more) to test out.

that requires a fair amount of time and effort.

the only person i know who has many copies of the same racket, is you, Cheung...

Originally posted by Cheung
wahh, what happened? how come no replies to my proposal?

1) nobody could be bothered to read it
2) read it but couldn't understand it:(
3) read it, understood it, thought it was idiotic and didn't reply:(
4) read it, understood it, thought 'what a crackpot', didn't reply:)
5) speechless because it was so brilliant:cool:

so why didn't you regulars reply?:p :D

6) all of above :p

scienctifically, the above test may lead to some conclusion but can be contested because:
1) the testers are human, subjective view can never be resolve
2) not enough variables being controlled

I suggest to expand the test and make it more rigorous
1) i would increase the rackets to 7 pairs as minimum from 3 pairs
2) each pair set racket must be same model and weigh exactly the same +/- 0.5 g or less
3) each set pair racket begin test with a machine hitting device to measure shuttle distance. If PT tension give more repulsion, shuttles should go farther upon each machine stroke. Machine hits limited to 7 shots per racket, ie, total 14 data points per set of racket, 7 data points for constant tension, 7 for PT.
4) no cross switching of rackets among testers, each pair must stay with the tester.
5) shuttles used must be super high grade feather, or plastic. This is to reduce the effect of shuttle degradation during test. New shuttle be used for each type of test: clear, drop and smash.


No need to say, the racket model be the same, same grip size, same string, same stringer using same machine pulled stringing done on same temp and humidity condition. The strings must come from the same batch and climatized in the stringing room for at least 2 hours with package closed.

The machine will yield quantitative data
Human testers will yield qualitative data

Originally posted by kwun
Cheung,

scientific. but logistically tough to do. to be really scientific about it, we not only need to have 3 rackets, but 3 identical rackets, all strung differently, all needs to be available at the same time.

we also need to have more than one data point, ideally, whoever performs the experiment needs to give those rackets to many people (at least 10, if not more) to test out.

that requires a fair amount of time and effort.

the only person i know who has many copies of the same racket, is you, Cheung...
there's 6 racquets total. If given to 5 different people each... i think we can push near 95% certainty using the right statistical methods... i can't think of the the equation right now (my stats books and progs in storage) but i'm sure i can dig it out. It was in the chapter after ANOVA... if that helps anybody?

Originally posted by bigredlemon
there's 6 racquets total. If given to 5 different people each... i think we can push near 95% certainty using the right statistical methods... i can't think of the the equation right now (my stats books and progs in storage) but i'm sure i can dig it out. It was in the chapter after ANOVA... if that helps anybody?

I dont think so.
ask yourself how many badminton players we have, the is your population.

I like Cooler's suggestion!! Except the machine hitting device cannot be easily obtained.

That's quite a lot of racquets.

Now I mentioned Dixon's up-down method before. Without going into details, we can use a smaller sample size. And we can use the same racquets (thus with ideal characteristics).

so get 2 racquets of same weight. Wrap them up exactly the same with same grip. One racquet is the standard, the other is the racquet that we adjust tension up and down. Of course, we need a seperate stringer who is willing to restring the racquets at the required tensions.

Cooler is right, there will always be variation in a biological system, but we can find a more practical means of getting to the right data that will help us. Being rigorous is good but if it is so tight that we can't do the experiment, we'll just be arguing on theorectical issues most of the time.:) Most of the medical research involving human subjects are like this (since humans [and likely badminton players:p]) show huge variation

Hey Kwun, I've weighed some of my racquets. Can't get to the tolerances that Cooler specifies on all of them.

Now if I had a stringing machine, I could probably do this experiment. It's too expensive to waste a set of strings each time. It's not the cost of strings but the labour charge. Doing the stringing by myself could cut down a lot on the cost.

If you prevent people from switching racquets, then you are throwing out a lot of possible detail. I.e. a medical test that has patients on a before/after or active/placebo flip time trial can achieve a higher level of certainty with far fewer people. Ideally you want to have 5 people as 3 is low, but if the difference between the racquets are clear, than 3 people switching racquets should give enough certainty to push the results beyond 95% confidence 19 times out of 20, which is the pretty much the standard.

You mention a lot of variables, but you don't need to control them if the difference between them is obvious. Since the variables don't matter much, the effort is better spent elsewhere: finding skilled players.

It's easy to feel the difference between a fresh racquet of the two string types by bouncing a bird on different areas of the racquet since I think the main problem with the test is no such much the precision but the validity. The blind field trial is a good idea but it's not really blind if the people know which is which. A more robust test is to have players play in a round-robin game facing everyone else, and all switching racquets each game.

I forget the name of this statistical test but this is how you do it:
We can then add up the points of each player to get a ranking. A higher ranked player should beat a lower ranked player by the average amount.

First, calculate the average points of each player. Subtract the difference between the average points of each player and that should be the point spread of a game between them. If the differnce is higher for the propportional stringing player, then that is a positive amount. Conversely if the constant tension strung racquet player wins then the value is a negative amount. We add up the points and map it onto the poisson distribution selected for the number of variables. (the n=3, n=3 grid i think)

This robust statistical test cancells out all the variables and is very sensitive. FYI it's called a poisson (fish) distribution because it was devised to measure the effect of different fishing methods on fish livestock i think.

Here's an example of how you would extrapolate average score per game to expect final score of the game. You find the difference between actual score and anticipated score. Using the statistical calculation above, you are effectively determining how much of difference you saw between actual and expected result can be determined to be from the stringing method.

on the chart, swap the heading label "averages" and "player" with each other. :o

I forgot to mention, the type of racquet given to each player at the start of the game can be determined with a dice or coin. I.e. if get "5" on a six-sided dice, then use racquet "5" etc.

Using the info above, we can also test if there is a difference between different racquets of the same model and specification. Useful for seeing how consistent Yonex makes their racquets.

BRL, conclusion drawn from statistical method will never be 100% certain, there'll be alway be some doubts to cloud up the issue been tested. Definitely a no no to use game scores to derived a conclusion about PT versus standard stringing, u r introducing whole bunch of variables (player's skills and attributes) that u can't never control. Reducing 7 to 5 or maybe 3 pairs of racquet is acceptable to me because of cost. If we can obtain a hitting machinge, i can live with 2 pair racquet. I forgot to mention that the stringing machine should be a electronic type since mechanical stringing machine has too much tension variation if we were to use 2 to 3 set pair of racquets for this experiment. I still believe plastic shuttle is better for the machine hitting test, feather shuttles are just too unconsistent. I also suggest using even number racquet pairs like 2, 4, or 6 (i retract my previous 7 racquets recommendation). I like to see the difference between oval and iso shape racquet too in PT versus standard stringing.

I'm sure this PT vs non PT test been done by many people before but likely in a unscienctifc way. That is why we are still debating this issue due to doubts in those test results. If u gonna do it u gotta do it right or doubts will waste the cost of doing the test in the first place. The cost is minimal if yonex done it since they have hitting machine, electronic stringing machine and identical rackets at their disposal. All is need is one man day time to string and conduct this test.

Originally posted by cooler
BRL, conclusion drawn from statistical method will never be 100% certain, there'll be alway be some doubts to cloud up the issue been tested. Definitely a no no to use game scores to derived a conclusion about PT versus standard stringing, u r introducing whole bunch of variables (player's skills and attributes) that u can't never control. Reducing 7 to 5 or maybe 3 pairs of racquet is acceptable to me because of cost. If we can obtain a hitting machinge, i can live with 2 pair racquet. I forgot to mention that the stringing machine should be a electronic type since mechanical stringing machine has too much tension variation if we were to use 2 to 3 set pair of racquets for this experiment. I still believe plastic shuttle is better for the machine hitting test, feather shuttles are just too unconsistent. I also suggest using even number racquet pairs like 2, 4, or 6 (i retract my previous 7 racquets recommendation). I like to see the difference between oval and iso shape racquet too in PT versus standard stringing.

I'm sure this PT vs non PT test been done by many people before but likely in a unscienctifc way. That is why we are still debating this issue due to doubts in those test results. If u gonna do it u gotta do it right or doubts will waste the cost of doing the test in the first place. The cost is minimal if yonex done it since they have hitting machine, electronic stringing machine and identical rackets at their disposal. All is need is one man day time to string and conduct this test.

Player's skill and atributes are already controled for by determining the difference between expected and actual score. IF it wasn't controlled for, i would have used by how many points did the person with PS racquet won over the CT racquet.

As for never being 100% sure: we can never be sure that we even exist. People have been trying to prove we exist for thousands of years and have no succeeded. We can never prove that any medicine has any effect on us. We can only determine what is likely. And that is what we are doing. That is what statistics is all about.

Cooler, you are worrying about a lot of variables but perhaps needlessly. Suppose every odd day of the month I run with ABC running shoes and every even day I wear XYZ running shoes. Suppose I run faster with ABC running shoes 95% of the time. This goes on for several years. I would say ABC running shoes is better.

Using your argument, you would say we cannot say which shoe is better since we cannot determine it with 100% accuracy like that. We need to determine air resistence of the shirt and shorts i was wearing that day, the wind speed, the temperature, etc etc.

None of those things matter in the long run of course because they are random. Everything cancells out. If you flip a coin 100 times, you'll get around 50 heads. Wind speed matters for each single flip, but the sum total.

That is why I'm comparing averages and their spreads. There will be big differences between players and differences between variables. But it does not matter because everything will be cancelled out. HENCE I used a possion distrubtion curve. It lets me determine how certain I can be of a result. If the sample size is too small for the variables, the statistical test will show that. I think the sample size I pick balances realistic possibility and likelihood of a statistically significcant result.

You no doubt will still feel there's some variable not accounted for somehow. I ask you to show me how that variable would not be averaged out by the statistical analysis I proposed.

Anyway the fluctuations in the variables does not affect the validity of the result if they are random. It merely reduces the likelihood of getting a statistically significant result.

The test would only be invalid if there is some variable that changes only with respect to one stringing type but the other for this test but not in actual use. If you feel such a variable exist, I urge you to find it and post it here. Like I said, I can't think of any variable not already accounted for if we are trying to determine which stringing type is better under the playing conditions I've mentioned.

BRL, Cooler. I agree with both your points.

Cooler's approach is the gold standard which will be very good and demanded of people with engineering degrees and physical inaminate objects.

For sure, in a biological system, nothing is 100% certain. That's why we have 95% probability.

Although we might test for PHTS under lab conditions. I am sure if we gave out the racquets to enough badminton players, one of them is going to state an opinion contrary to lab tests. That's just being human:p

BRL, I'm not sure playing games and adding up the points total/averging them out is the best way. Over many, many games, yes. Too many other factors get involved.

I would suggest keeping it simple and give each player a range of shots to test out the racquets

e.g. 10 shots on clears, 10 on smashes, 10 on drops.....
then give a rank.

Your test on points scored is affected by player performance that day, mental feeling, variability in players psychology, fitness level....
My original suggestion was to code each racquet so the users do not know which tension or method the racquet they use is strung at and, like you said, allow them to use all the different racquets.

Originally posted by Cheung
Your test on points scored is affected by player performance that day, mental feeling, variability in players psychology, fitness level....
My original suggestion was to code each racquet so the users do not know which tension or method the racquet they use is strung at and, like you said, allow them to use all the different racquets.
Although the test i propse would be affected by that, the performance difference should apply regardless of which racquet they are using, and thus averages out. When we compare the difference use of two racquets, all variables that apply equally to both are cancelled.

Your initial test is based upon a blind trial, but that is not possible because a good player would be able to tell what type of stringing method was used, so it's not really a blind test at all. Since we are only interested in which method allows better play, we should look to performance differences during play.

As for there not being enough datapoints, I agree that is a definte possibility. If the variation between games is too much higher than the difference between the effects of the two stringing methods, then we would need more people. But even that random variation is a point-spread difference of 4 points (i.e. win by +/- 2 points) and the effects of the stringing method is allowing one to score greater than 1 point, we have enough people to detect the difference. If the difference isn't even big enough to make more than a single point difference on average, then it's enough to show that we are worrying over small potatoes!

Also note that my test and your test isn't exclsuive. If you have the people on the courts, why not play a few games (only need 3 games per person) after your tests? For reasonable radnom variations between performances, I think the test is sensitive enough to pickup differences in performance that is small enough to matter. Any smalelr than that, then the difference isn't worth consideration.

cheung read my mind, cooler wants 100% certainty because it is obtainable.
Under 95% certainty, the remaining 5% would never be resolved until every badminton players in the world conducted this test. That remaining 5% will alway still have doubts about PT stringing.

For examples
1. there are people still believe (with their own evidence) that american never been to the moon
2. there are people believe 9/11 was conspired by US gov't because US air force did nothing to stop the plane
3. with photos and other evidences, the existence of alien and sasquatch are been constantly debated.

As u can see, empirical/statistical method is never 100% certain but for those cases that we have no scientific test to obtain 100% certainty, we reluctantly accept those empirical/statistical results in order to make life easier.

OK, here is a variable that will throw a snag into using score to derive conclusion about PT versus normal string. How long will each player be using the test racquet as PT string tension degrades with each shot. I can assure you that each game will not have the same time duration, same among of smashes, drops, clears. Therefore, each and every test racquet will have different tension. Is the player gonna mentally keep track performance of each racquet? For example, hmm, 42 smashes on the first game using racket A, and 67 smashes on racket B and 46 smashes on racket C, and so on. Also, player A may smash 20% harder than player B, and if you start switching rackets, you have loss control on all your test variables. Also players may feel weaker near the 3rd, 4th and fifth game, how's that affect his judgement on the racket/string performance?

just to say to BRL, we are just debating the merit of way to test PT vs non PT stringing, i'm not attacking you personally (unless u r on the other side of the badminton court :p )

Originally posted by cooler
cheung read my mind, cooler wants 100% certainty because it is obtainable.
Under 95% certainty, the remaining 5% would never be resolved until every badminton players in the world conducted this test. That remaining 5% will alway still have doubts about PT stringing.

[...]

OK, here is a variable that will throw a snag into using score to derive conclusion about PT versus normal string. How long will each player be using the test racquet as PT string tension degrades with each shot. I can assure you that each game will not have the same time duration, same among of smashes, drops, clears. Therefore, each and every test racquet will have different tension. Is the player gonna mentally keep track performance of each racquet? For example, hmm, 42 smashes on the first game using racket A, and 67 smashes on racket B and 46 smashes on racket C, and so on. Also, player A may smash 20% harder than player B, and if you start switching rackets, you have loss control on all your test variables. Also players may feel weaker near the 3rd, 4th and fifth game, how's that affect his judgement on the racket/string performance?
I mean 95% certainty as in 95% that the result is right, as in if we did this test 100 times, it would give the correct answer 95% of the time. Whether or not 95% of the people will believe the test is something else altogether.

As for the degredation of PT, that itself does not go to the validity of the test. It merely reduces the effect and hence increase the chance of giving an inconclusive result.

As for mentally keeping track of the racquet: that is the beauty of what I'm proposing. The players don't need to keep track of anything. They just play as best they can. The problem with Cheung's method is that in my view the players will know (or think they know) whether their racquet has PT or not, and thus bias their results when they remember which racquet they like better.

For players getting weaker: that does not matter either because they have an equal chance of getting the PT vs CT racquet at any time. Being prone to fatigue well reduce their average but not affect how they play with only one racquet. They will play worse with both PT and CT racquets when they are tired. I say it does not matter because suppose fatigue ONLY affects CT racquet but not players using PT racquet. The test would favour the PT racquet and rightly so because it *is* better since it's use is less susceptible to fatigue.

If I wasn't clear before let me clear this up: after every game, a dice is rolled to see who gets what racquet. All random. One might get one type one game and not another. It's possible to have PT v PT and CT v CT. One might get PT or CT all three times. The randomness of this design ensures the only differences are the differences we want to measure.

Let me know if there's anything else I havent covered or covered clearly. And of course I know you aren't attacking me personally and same with me to you of course. Most of the time I don't even look to see how posted it when I respond :p.

Originally posted by cooler
cheung read my mind, cooler wants 100% certainty because it is obtainable.
Under 95% certainty, the remaining 5% would never be resolved until every badminton players in the world conducted this test. That remaining 5% will alway still have doubts about PT stringing. I agree, but if you are dogmatically standing on your 100%, that might be an even further time span away. we could get some relevant data earlier which might be helpful in the interim.

Originally posted by BRL
The problem with Cheung's method is that in my view the players will know (or think they know) whether their racquet has PT or not, and thus bias their results when they remember which racquet they like better. It's already been accounted for by coding the racquets. The user will not know which method has been used. They have to give thei impartial assessment.

Originally posted by BRL
For players getting weaker: that does not matter either because they have an equal chance of getting the PT vs CT racquet at any time. Being prone to fatigue well reduce their average but not affect how they play with only one racquet. They will play worse with both PT and CT racquets when they are tired. I say it does not matter because suppose fatigue ONLY affects CT racquet but not players using PT racquet. The test would favour the PT racquet and rightly so because it *is* better since it's use is less susceptible to fatigue. No, I'm sorry there. I think it will make a difference. This is an important issue because different people's shot quality suffers at different rates. You are assuming that a player can last the test. Some people can only play one game and then need a 20 minute rest and may refuse to play anymore games. Also, this method assumes that better playability equates to more points. Now that may not necesarily be the case. That's why a standardised shot is much better tham looking at points scored.

I think you're blinded with science, specifically with statistical science.
Why resort to statistic when there's a direct clear cut way to derive a conclusion? When your start rolling dices in a experiment, you are dealing with chance instead real hard science. Using your score based method, we can evaluate shoes, grip brands, socks, etc right? Statistically, badminton is dominated by asian countries, does this prove that asian make the best badminton players? I highly doubt that.

Originally posted by Cheung
No, I'm sorry there. I think it will make a difference. This is an important issue because different people's shot quality suffers at different rates. You are assuming that a player can last the test. Some people can only play one game and then need a 20 minute rest and may refuse to play anymore games. Also, this method assumes that better playability equates to more points. Now that may not necesarily be the case. That's why a standardised shot is much better tham looking at points scored.
Play quality does suffer at different rates, but how does that make a difference? The average is derived as the average throughout the entire set of games, so it is already factored in.

If playability does not mean more points, than why should we care about that at all?

Originally posted by cooler
I think you're blinded with science, specifically with statistical science.
Why resort to statistic when there's a direct clear cut way to derive a conclusion? When your start rolling dices in a experiment, you are dealing with chance instead real hard science. Using your score based method, we can evaluate shoes, grip brands, socks, etc right? Statistically, badminton is dominated by asian countries, does this prove that asian make the best badminton players? I highly doubt that.
Random trials are fundamental to to scientific tests. If you take that away, then you have pseudo-science. This is why Cheung is labelling the racquets with a code the players will not recognize. I'm saying that may not be sufficiently blind and could introduce bias into the result.

Suppose you have a coin weighted on one side but you don't know (analogous to our experiement.) You can have a person look at the coin to see which side looks heavier or you can flip the coin a few times and see which side it lands on the most. Cheung's test is closer to the first example since it relies on subjective impressions, which are especially vulnerable to bias. My suggestion is closer to the latter example since it relies on quantitative measurements. Although flipping the coin does introduce randomness, It's a far stretch to say i'm introducing chance into the experiment.

As for your example, you are confusing a statiscal test with a fact. You stated a fact. A known cannot be the result of a statisitc test itself. The statistical test I proposed gives three possible answeres: PT is near-certainly better than CT, the converse, and there is no significant difference. Compare this statisical answer to your statisc of "Asian countries dominate badminton" and you see what are talking about different meanings of the word "statisics."

Originally posted by bigredlemon
Play quality does suffer at different rates, but how does that make a difference? The average is derived as the average throughout the entire set of games, so it is already factored in Cooler went through that
Originally posted by bigredlemon
If playability does not mean more points, than why should we care about that at all? Now, that is an excellent question. I did a review of some strings way back and for one of them I wrote (words to effect) 'it feels better but wether it means making a difference in getting more points...' Sure, I understand, better playability SHOULD equal more points but that is an assumption we actually haven't proven satisfactorily for the rigors of this test. The original question asked for playability...

Originally posted by bigredlemon
Random trials are fundamental to to scientific tests. If you take that away, then you have pseudo-science. This is why Cheung is labelling the racquets with a code the players will not recognize. I'm saying that may not be sufficiently blind and could introduce bias into the result. It is definately sufficently blind. If the player doesn't know what technique and tension the racquet is strung at, and the person who hands him the coded racquet doesn't know either, that is a definately acceptable double-blind trial and will be accepted as such in very prestigious medical journals. You'll have to explain very clearly where the bias comes in. Since the measurements I am proposing are subjective measurements, that's where the stats come into analysing (and also larger population sample).

in your test brl, what type of players will you be using to test the racquets? Surely C and D players wouldn't appreciate the different between PT vs CT strung rackets so the game score data collected will be good as garbage. How good is good enough of a player for your method of test? Do u know that human skills is never a constant? As games are played, each player gain experience at differenct pace. How would u separate out the score gain is from PT instead of synergy gain/loss in doubles? You can never take out the bias factor. What if some test players were accustomed to CT and never used PT strung rackets before and he's chosen in your statistical test. Wouldn't his poor showing from using PT racquets distort your pure randomness or maximum entropy objective?

Originally posted by Cheung
Cooler went through that
And I answered that before. So i'll say it again i guess.
Player A's expected score
15-10,
13-15,
5-15.

Player B
6-15
12-15
15-13

So player A clearly tires out much fast than the other players. His average points is 11 points per game. Player B has much better endurance and also has 11 points per game. They both play at a similar level over three games.

So suppose A plays B. A's score is
15-8 (CT v PT)
15-13 (PT v CT)
7-15 (CT v PT)

A's average is 12.3. B's average is 12. For each game the spread is expected to be zero but is instead 7, 2 and -8 for player A and opposite for player B. We add them up for a total of (-7+2+8=+3) for PT and (7-2-8=-3) for CT. Hence PT more effective than CT.

So suppose A plays B. A's score is
15-6 (CT v PT)
14-15 (PT v CT)
8-15 (CT v PT)

Spread is 9, -1, -7. PT=(-9-1+7=-3) and CT=(+3) Hence CT more effective than PT.

Thus we see that even if the fatigue pattern is maintained, the test still gives an answer to which stringing method is better because the test doesn't care how well you perform on any particular game. The test ONLY looks at whether your the pattern of points, given the level of your opponent, correlates to the stringing method used. Regardless of whether one gets tired faster or slower, the effects, if any, willl be shown by finding the difference between expected and actual. The only difference being selectively manipulated is the stringing method... all other variables are randomly sorted.

The same holds true if I make a list of a matrix of 4x4 players but then that would be needlessly long (15 games per player to consider.) The same reasoning applies anyway. By the way note that the expected poitns was not used in the calculation itself; that is determined from the actual games. I only mentioned that to show that the skill of a player over X many games can be reduced to a single number.

So again, how is the different endurance levels not addressed? I think I've shown that it has been. I can't think of any concrete examples where your statement would be consistently true.

Originally posted by cooler
in your test brl, what type of players will you be using to test the racquets? Surely C and D players wouldn't appreciate the different between PT vs CT strung rackets so the game score data collected will be good as garbage. How good is good enough of a player for your method of test? Do u know that human skills is never a constant? As games are played, each player gain experience at differenct pace. How would u separate out the score gain is from PT instead of synergy gain/loss in doubles? You can never take out the bias factor. What if some test players were accustomed to CT and never used PT strung rackets before and he's chosen in your statistical test. Wouldn't his poor showing from using PT racquets distort your pure randomness or maximum entropy objective?

If you look at the example I just gave, you noticed that each game contributes some points to the CT v PT graph. People who appreciate the difference between the methods will show more difference in the play, and hence contribute more to either one or the other stringing method. If no one can appreciate the difference enough *or* if there's no difference, then the value on both sides will be randomly added and subtracted, and hence amount to a coin flip.

Flip a coin 50 times, and record the head and tale values. Subtract the difference between the two. You'll find that value is very likely to be 5 or less. That's what I'm doing. After both sides are tallied up and subtracted, then we would have a value. If that value is below some threshold, it would be considered random noise and hence we would have no significant difference between the two stringing types. That threshold value is determined by the spread between expected (from the average)and actual game scores.

Also note that I specifically said the test was to be performed by singles matchups. Doubles can also be done but the matrix would be 3-D instead of 2-D and I can't draw 3-D to show you what I mean. The effects of the partner can be regressed out just as the effect of fatigue can be regressed out. I hope you don't ask me to prove that to you since the last time i did something like that it took me 3 days and over 20 pages. In any case i'm sure you can inuitively understand how that would work. I.e. if a doubles player is really good, his partner would be expected to do better than if he really sucked.

As for being accustomed or not to the PT method, that is a valid concern. Note that it affects Cheung's method exactly as it affects mine the way I presented it. Also Note that I can test to see whether the spread difference increased at later games compared to earlier games, and hence be able to correct for the learning curve. That would cancel out the learning curve effect if that curve is noticeable.

Also note that for my test, the games need not be to 15. It could be to 11, 7 or 5. Whatever makes them happy. Just get more games in if playing shorter games.

That should cover everything... or is there still something that you're not convinced with?

Originally posted by cooler
What if some test players were accustomed to CT and never used PT strung rackets before and he's chosen in your statistical test. Wouldn't his poor showing from using PT racquets distort your pure randomness or maximum entropy objective?

I agree that this is a factor which may influence the test results significantly.
But wasn't it, for instance with speed skating, that not everyone liked the clapskates in the beginning. At the end of the nineteenth century, this method was already invented in Canada. Only after lots of testing and constant good results, everyone now uses them, as it has proven to be faster then conventional skates.

I'm not trying to say that it's the same with proportional stringing, but who knows, maybe everyone is wasting too much energy hitting with constant stringing method.

For good test results, it may be preferable to let a group of professionals swich to PT for a longer period of time and then review the results.

I think Cheung's test is nice to see if there is some base to believe or asume that PT is better than CT or the other way around.

Furthermore, my feeling of this test is, when either PT or CT comes out as a big winner, one can make some sort of conclusion :
- If PT is overwhelmingly experienced as best, this method is surely interesting to be further tested (for better tournament results !) by professionals players for a longer period of time.
- if CT is experienced as best, one may reconsider why bother to promote PT, further testing by professionals may not be worth the energy.

Other than that, when it's in the 50-50 area, it may be interesting to do testing on a larger scale.. which may be useless after all, or not .... :rolleyes:

that's true yong, some engineering innovations clearly stands out as improvement like clapskates - simple to understand - better mechanical leveraging translates to linear power, no brainer. The reason (my postulation) why it took so long to become accepted in competition because it was considered illegal or questionable for sanctioned skating competition and not because there was doubt of it advantage. This can be also said for golf with those trampoline effect head surface which clearly can drive the ball farther but ruled illegal on tournament because PGA has rules for equipment standard. Let take this analogy to badminton, if yonex makes a racket 20mm longer than normal, i can assure you that statistical data would support lab test that the shuttle will be hit faster than a regular length racket. Certain improvements just stands out.

Since badminton is just as old as speed skating (1924) if not longer, i'm sure stringer since the beginning of badminton time had dabbled with PT stringing. How come we don't have a conclusive favorite pattern yet between PT and CT ?? This again support that game score statistical method will not resolve the good and bad of PT versus CT. Even if PT is better than CT, is it worth it and how long the advantage last. As for clapskate, the leveraging advantage remain intact even after 100 year, PT pattern doesn't, it changes after every shot.

As for being accustomed or not to the PT method, that is a valid concern. Note that it affects Cheung's method exactly as it affects mine the way I presented it. Also Note that I can test to see whether the spread difference increased at later games compared to earlier games, and hence be able to correct for the learning curve. That would cancel out the learning curve effect if that curve is noticeable.

Every player will have different learning curve. Of course, statistical method will draw to some kind of conclusion but u need to play thousands of games (if not million) in order to remove the noise so that the PT vs CT effect can be revealed. That is why after more than 100 years of badminton, PT vs CT is still very cloudy.

Originally posted by bigredlemon
The effects of the partner can be regressed out just as the effect of fatigue can be regressed out. I hope you don't ask me to prove that to you since the last time i did something like that it took me 3 days and over 20 pages. In any case i'm sure you can inuitively understand how that would work. I.e. if a doubles player is really good, his partner would be expected to do better than if he really sucked.

Also note that for my test, the games need not be to 15. It could be to 11, 7 or 5. Whatever makes them happy. Just get more games in if playing shorter games.

It wouldn't be useful to test it for doubles pairs at this moment. Why bother when even the simple issues haven't been resolved? We should take taking on the problems on step at a time

Fair enough the shorter games will resolve the fatigue problems. There are other issues that might affect the result (getting used to the hall, getting into the frame of mind of playing on that day, different performance on different days, loss of string tension within the playing time etc). All these factors affect professionals as well. I suspect the difference in playability between the two methods is small (if any) and the extra extraneous factors I mentioned will reduce out the differences. I don;t know for you but for people I play with, sometimes I win sometimes I lose. Sometimes I win by a huge amount, more often I lose by a huge amount. Sometimes this occurs in the same night playing the same person.

Originally posted by bigredlemon
So player A clearly tires out much fast than the other players. His average points is 11 points per game. Player B has much better endurance and also has 11 points per game. They both play at a similar level over three games. Level of play can vary within the game. Does the statement in bold mean that the level of variation in level of game is constant?

What I suggested will be also be viable in terms of practical issues like time.
Time because we wouldn't need all players to congregate at the same time playing a round robin. We'd need to book a few courts at one time and ensure each participant can turn up.

For the method I suggested, we could just bring along a few freshly strung racquets, give to player A one night for standardised assessment, then another night, have the racquets restrung to give to player B for assessment etc. Then we can lots of tests.

Yup, I agree there is possible adjustment to PT method that may affect result.


Here is a true story:
I was speaking with an international player about his stringing tension (at the time I was unaware of PT). Being a fulltime player at the HK Sports Institute (reputation of player is sound[has beaten Sigit/Chandra before]), he told me his stringing tension was 30lbs for the 2 point machine and low 20's for the electronic machine. I asked him why the difference? Answer: shrugs shoulders i.e doesn't know.
Another international singles player[has beaten top ten singles players] couldn't even tell me what tension he used!!!

that is true cheung, most top players aren't too picky about the tension or strings of their rackets, as long as it was done the same way as before. I have asked one MS silver medalist what tension he uses, he said 29 lb, i ask why, he said that was the tension of his racket when he started playing badminton when he was a kid.

my last words on BRL's statistical method. There are tons of variables in game playing. To squeeze a PT vs CT trend from the data, u need lots and lots of games played to 'cancel out' the other noises. Since this involve time, and human mood and physical change with time(we all ages u know). So in itself, variables are changing with time. You have to play more and more games just to cancel out those changeing variable. So in the end, more games need to be played just to remove the noise and your quest to learn PT vs CT WILL NEVER BE found statistically in one's lifetime, assuming same players must be used continuously for this test.

Originally posted by Yong
Furthermore, my feeling of this test is, when either PT or CT comes out as a big winner, one can make some sort of conclusion :
- If PT is overwhelmingly experienced as best, this method is surely interesting to be further tested (for better tournament results !) by professionals players for a longer period of time.
- if CT is experienced as best, one may reconsider why bother to promote PT, further testing by professionals may not be worth the energy. i was under the impression that pros already prefer PT and use that method almost exclusively. Though at 30+lb, they don't have much of a choice either. Even if CT is better, pros have to use PT because their racquets can't handle CT at those tensions.

Originally posted by cooler
This again support that game score statistical method will not resolve the good and bad of PT versus CT. Even if PT is better than CT, is it worth it and how long the advantage last. I beg to differ! People also said man would not leave land/ground/earth/solar system. 3 out of 4 ain't bad, and #4 is probably within 80 years. There's probably some way of doing it with stats though stats aren't always the best way to do it.

Originally posted by cooler
Every player will have different learning curve. Of course, statistical method will draw to some kind of conclusion but u need to play thousands of games (if not million) in order to remove the noise so that the PT vs CT effect can be revealed. That is why after more than 100 years of badminton, PT vs CT is still very cloudy. A million is a far stretch. Thousands is also a far stretch. I'm confident that any appreciable difference between the two could be pickedup under 50-100 games total. For a 4x4 round robin, i think it's sensitive enough to pick it up. As for historical use of the test, i don't think it was even proposed until the mid 1970s. As far as I know, this test is still on the upswing of things. Even in medical literature where you would expect to see the poisson curve used more often than the standard curve, i find it's often the other way around.


Since you are so convinced that the randomness is going to be high, let me ask you to do this:

make up 4 players. Name them Al, Bob, Carl, and Danny.

Makeup some arbitrary skill rating for each player. (Good players tend to beat poor players, most of the time.)
[i.e. Al = 2, Carl = 4]

Pair up each player in a 4x4 grid that i mentioned before.
Assign them points (the score for the match) according to their skill level.
[i.e. Al v Carl, 8-15]

Now add randomness to the score. Use whatever amount of randomness you think represent a reasonable typical game.
[i.e. Al v Carl, score +/- some number to 15 *or* 15 v +/- some number]


Makeup some fatigue value for each player, and add fatigue effects to the score:
For "fit" players, add points later rounds and/or subtract points for earlier rounds.
For "unfit" players, do the opposite.
this means you also has to decide who plays who and when.


Now decide who has PT and who has CT racquet for each game. Flip a coin to decide to make it random... don't pick youself. Players can have all or none of the same stringing type and both players can use the same or different type in any match.

Now add or subtract some pointage for one racquet type and do the opposite for the other racquet type. You decide how many points to add or subtract so long as it's consistent. You can add more points or less points on different rounds to mimic the learning curve.


Now send me the following info:
who player who during which round and what was the score. I'll tell you whatever the stats test tells me.

That covers about all of your objections right?
Sounds fair?

go go go!

Originally posted by Cheung
It wouldn't be useful to test it for doubles pairs at this moment. Why bother when even the simple issues haven't been resolved? We should take taking on the problems on step at a time
Agreed... don't want to do all that math right now.


Fair enough the shorter games will resolve the fatigue problems. There are other issues that might affect the result (getting used to the hall, getting into the frame of mind of playing on that day, different performance on different days, loss of string tension within the playing time etc). All these factors affect professionals as well. I suspect the difference in playability between the two methods is small (if any) and the extra extraneous factors I mentioned will reduce out the differences. I don;t know for you but for people I play with, sometimes I win sometimes I lose. Sometimes I win by a huge amount, more often I lose by a huge amount. Sometimes this occurs in the same night playing the same person.

Fatigue problems are irrelavant anyway becauses it's inherently factored into the calculation. Shorter games would mean more datapoints though and hence greater precision and sensitivity. As for the performance issuesL: they may matter to the player but not to the test. At a tournament, you can determine how well someone plays by looking at his mental state and racquet tension and what he ate for breakfast and how long his hair is and whether he shaved or not, or you could look at how he played at the last tournament. More number of factors does not equate to more precision. It only means more math.

There usually is differences in play, but those differences are affected by factors as you said. So long as those factors are not correlated to the type of stringing your racquet used, they should cancel out. Even if they don't cancel out because it DOES correlate with the stringing type, that could still be considered as a performance factor relavant to you so it's useful anyway. So that is why the test is so great: all the differences that's affected by the stringing type is recorded but all others is not (in the long run anyway.) So in the long run, you can determine the effect of anything.



Level of play can vary within the game. Does the statement in bold mean that the level of variation in level of game is constant?
variation during a game is irrelavant since only the final score of a game is considered. I think that's what you meant?



What I suggested will be also be viable in terms of practical issues like time.
Time because we wouldn't need all players to congregate at the same time playing a round robin. We'd need to book a few courts at one time and ensure each participant can turn up.

Yea my test presumes you can get enough courts to play everything in one go. This doesn't have to be the case however. The test could be modified to presume a new "set" of players are used on different days even if it is the same people, although this method would require many more games and hence not be practical. If the court limitation is a problem, then your way may be the only feasible way.


For the method I suggested, we could just bring along a few freshly strung racquets, give to player A one night for standardised assessment, then another night, have the racquets restrung to give to player B for assessment etc. Then we can lots of tests.

Yup, I agree there is possible adjustment to PT method that may affect result.

That sounds like a good idea but make sure you don't always string the same racquet with the same type because then you won't know if you are seeing differences with stringing or with the racquet itself.


Here is a true story:
I was speaking with an international player about his stringing tension (at the time I was unaware of PT). Being a fulltime player at the HK Sports Institute (reputation of player is sound[has beaten Sigit/Chandra before]), he told me his stringing tension was 30lbs for the 2 point machine and low 20's for the electronic machine. I asked him why the difference? Answer: shrugs shoulders i.e doesn't know.
Another international singles player[has beaten top ten singles players] couldn't even tell me what tension he used!!! didn't you also tell us a story a few months (last year) in which a friend of yours could tell the tension of the racquet by merely hearing the tone it made when it cleared a bird?

I've been practicing that lately and I think i can guess within 2lb around 2/3 of the time. I haven't done this often though so it might have been luck.

Originally posted by cooler
my last words on BRL's statistical method. There are tons of variables in game playing. To squeeze a PT vs CT trend from the data, u need lots and lots of games played to 'cancel out' the other noises. Since this involve time, and human mood and physical change with time(we all ages u know). So in itself, variables are changing with time. You have to play more and more games just to cancel out those changeing variable. So in the end, more games need to be played just to remove the noise and your quest to learn PT vs CT WILL NEVER BE found statistically in one's lifetime, assuming same players must be used continuously for this test.
cancelling out those variables does not need to be perfect... a fuzzy estimate is good enough. In the long run, all error will be cancelled out and only factors relating to the stringing type will remain. I think we can both agree on this?

Only argument that remains is that I assert it would take a dozen or so games of that matrix for the statistic to give a statisically significant result (as in a positive result stronger than error with 95% probability) while you assert it would take a thousand games. A dozen or a thousand? We will see... after you tell me your numbers!


wow i cant belive i just spent 1.5 hours typing this... when i could have been sleeping! only got 2 hours sleep last night... :(

Sounds fair BRL.

BRL, you said outside variables are irrelevant because they will all be canceled out in the long run. True but you have no comprehension of the word LONG run mean in this case. Let me partially list some of the outside variables that will affect the score and needed to be canceled out.

1. level of wear of shoes (assumes same brand of shoes are used)
2. level of wear of socks ( " " socks " )
3. amount of rest prior to games
4. amount of glycogen stored in body
5. amount of food stored in digestive tract
6. cardio vascular condition for that day
7. mood condition (angry, sad, happy, content, etc…)
8. humidity of the air (assume constant ambient temperature)
9. level of wear of overgrip
10. condition of shuttles (assumes same brand and speed are used)
11. degree of string tension loss
12. and finally, PT vs CT stringing

So from a partial list of the top of my head, 12 variable will be interactively affecting a player's game.
12! = 479,001,600 of different arrangement of variables. Giving you the benefits of the doubt of needing only 1 match to filter each unique set of the 12 variable and assum 1 match = 2.5 games. So statistically, you need to plan, supervise and calculate results for 1.19 billion games. Hey wait, don't forget testing PT vs CT at different tension because PT may excels in 30+ lbs but sucks at <25 lbs. So, using a large increment of 1 lb between 18 to 32 lbs, we can add 14 more variables to the above 12. Hmm let see, 26! = 4.03 e26 which then required 1 e27 number games.

Now you go go go arrange this experiment and find willing volunteers to play the above amount of games. I was previously being very conservative saying that it would require thousands to millions of games. If you do, I would still find doubts in your results because I haven't listed ALL the variables.

If you just want 95% confidence level, you can reduce the amount of game played but i'll let you calculate that.

Originally posted by cooler
Sounds fair BRL.

BRL, you said outside variables are irrelevant because they will all be canceled out in the long run. True but you have no comprehension of the word LONG run mean in this case. Let me partially list some of the outside variables that will affect the score and needed to be canceled out.

1. level of wear of shoes (assumes same brand of shoes are used)
2. level of wear of socks ( " " socks " )
3. amount of rest prior to games
4. amount of glycogen stored in body
5. amount of food stored in digestive tract
6. cardio vascular condition for that day
7. mood condition (angry, sad, happy, content, etc…)
8. humidity of the air (assume constant ambient temperature)
9. level of wear of overgrip
10. condition of shuttles (assumes same brand and speed are used)
11. degree of string tension loss
12. and finally, PT vs CT stringing

So from a partial list of the top of my head, 12 variable will be interactively affecting a player's game.
12! = 479,001,600 of different arrangement of variables. Giving you the benefits of the doubt of needing only 1 match to filter each unique set of the 12 variable and assum 1 match = 2.5 games. So statistically, you need to plan, supervise and calculate results for 1.19 billion games. Hey wait, don't forget testing PT vs CT at different tension because PT may excels in 30+ lbs but sucks at <25 lbs. So, using a large increment of 1 lb between 18 to 32 lbs, we can add 14 more variables to the above 12. Hmm let see, 26! = 4.03 e26 which then required 1 e27 number games.

Now you go go go arrange this experiment and find willing volunteers to play the above amount of games. I was previously being very conservative saying that it would require thousands to millions of games. If you do, I would still find doubts in your results because I haven't listed ALL the variables.

If you just want 95% confidence level, you can reduce the amount of game played but i'll let you calculate that.
Althought the error buildup is hypothetically possible, it is highly unlikely. If you look at random noise, it has an average volume. That average stays the same most of the time.

Take your list of twelve variables. Lets pretend they can only make your game extremely good or extremly bad. The odds of all those variables going towards one direction to affect the game is 1 in 16384. Those aren't good odds cooler. That's the chance that one of us will get struck by lightling within tommrrow. It's possible, but it's not going to keep me indoors all day. In reality however, extreme differences are rare, and most of the time things are the same.

Consider a coin, any coin. You flip it. Whether it lands as heads or tails depends upon:

the twist of your wrist
the density of the coin
the purity of the coin
the width of the serated edges
the length of the serated edges
the depth of the serated edges
the width of the coin
the length of the coin
the depth of the coin
the smoothness of the curves on each side
the difference in smoothness of the curves on each side
the difference between the weight of the coin down the axis
the moisure in the air
wind speed
location of the moon, mars, jupiter, sun, etc etc
the stickiness of your hand's oil
the temperature
electromagnetic radiation of the sun
neutrinos emitted by black holes
etc
etc

i could spend all day listing things that could affect whether it is a head or tail. yet despite thousands of variables a coin flip is consistent... because all the variables are random. they cancel each other other. For each variable might cause the coin to flip to the left, there is another variable to cause the coin to flip to the right. There's many many variables, and on average they all work against each other.

How many coin flips does it take, on average, for you get a statistically significant value or whether the a coin is weighed towards one side or not? It's a lot less than one thousand. It's actually 14 if my memory serves.

BRL, if u look at that way, u r putting subjective bias into this exercise and you won't be conducting a true test. Also, lets be realistic, I have and u didn't. My list of variables is realistic and they do and will happen. People's mood will change, the time of and content of dinners will change, humidity affects the shuttle flight characteristic, string tension and my chap fingers. I too could include sun spot cycles and moon phases too but I didn't.

Let me dissect your other variables:

the twist of your wrist
the density of the coin
the purity of the coin
the width of the serated edges
the length of the serated edges
the depth of the serated edges
the width of the coin
the length of the coin
the depth of the coin
the smoothness of the curves on each side
the difference in smoothness of the curves on each side
the difference between the weight of the coin down the axis
wind speed (It's indoor, why make the experiment more complicated than needed)
the temperature (I assumed constant T for the racquet experiment too)

All of the above u called variables are really FIXED, CONSTANT, NOT variables. The coin u used don't change just like the racquets and strings used in our experiments are of fixed dimension and weight.

If you discount that 1 in 13684 of my variables are steered to one direction and they are insignificant and rare, then your assumption of self cancellation of noise is not perfect. Just read some posts here in this forum, sometime some have killer games while some other time they suck, with no apparent reason or explanation. Why? It's because there are so many variables that even they themselves can't identify them. You just can't disregard these extremes happen 1 out of 13684 their games.

You cannot discredit my list of variables as average background noise with average volume (amplitude). When one is tired or hungry or in a bad mood, he/she will can't concentrate and ability degrade. In your coin toss example, the variables are very limited, that is why the average outcome is 50/50 and the standard deviation is very very narrow.

Originally posted by cooler
BRL, if u look at that way, u r putting subjective bias into this exercise and you won't be conducting a true test. Also, lets be realistic, I have and u didn't. My list of variables is realistic and they do and will happen. People's mood will change, the time of and content of dinners will change, humidity affects the shuttle flight characteristic, string tension and my chap fingers. I too could include sun spot cycles and moon phases too but I didn't.

Let me dissect your other variables:

the twist of your wrist
the density of the coin
the purity of the coin
the width of the serated edges
the length of the serated edges
the depth of the serated edges
the width of the coin
the length of the coin
the depth of the coin
the smoothness of the curves on each side
the difference in smoothness of the curves on each side
the difference between the weight of the coin down the axis
wind speed (It's indoor, why make the experiment more complicated than needed)
the temperature (I assumed constant T for the racquet experiment too)

All of the above u called variables are really FIXED, CONSTANT, NOT variables. The coin u used don't change just like the racquets and strings used in our experiments are of fixed dimension and weight.

If you discount that 1 in 13684 of my variables are steered to one direction and they are insignificant and rare, then your assumption of self cancellation of noise is not perfect. Just read some posts here in this forum, sometime some have killer games while some other time they suck, with no apparent reason or explanation. Why? It's because there are so many variables that even they themselves can't identify them. You just can't disregard these extremes happen 1 out of 13684 their games.

You cannot discredit my list of variables as average background noise with average volume (amplitude). When one is tired or hungry or in a bad mood, he/she will can't concentrate and ability degrade. In your coin toss example, the variables are very limited, that is why the average outcome is 50/50 and the standard deviation is very very narrow.
a few bad examples in the list bad i think you understood my gist. Maybe I should rephase it. Suppose all those variables do affect the game. How would that affect the result? There no logical reason for someoen who just ate dinner to be luckier and get one stringing type more often than another. Even if there is a logical reason for that to occur, then that is some property of the stringing method and hence worth the consideration anyway.

You seem to suggest in your original post that I would need to know the exact values of those variables in order to get a true result. Prove it. (It's easier to contradict a proof than to make one up... esp since i havent slept in a while.)

amongst these statistical validity talk. i am going to report my findings on my experiment with PT stringing and string shifting, etc.

i brought two identical rackets, both brand new cab20 to my stringer. i told him to string them @25lbs for the middle 6 mains, decreasing one lb per string from then on. for cross, 26lbs for the middle 8 mains, descreasing one lb per string from then on. after i got the rackets back, i used a permanent marker to mark the location of the string, then i only used one of them. the other one travels with me in the bag, but never get used. in fact, i still haven't used it after 2 weeks.

the other one i have been using for the last two weeks, during all training and games and drills sessions, i must have put at least 10-15 hours on it.

so the goal of the experiment is to see how much the string shifts while playing.

the result? ZERO. comparing the two rackets, neither of them changed.

that is to our surprise, as we were expect some string shift.

so here is the story. i brought my rackets to my stringer 2 weeks ago saturday. and i told him that i will pick them up tuesday. being so diligent that my stringer was, he had them all strung and left on the shelf on sunday. the racket sat there for two days before i pick them up. i think what happened during those two days was that they already gone through the shifting. and i marked the string too late therefore i didn't see any shifting at all.

so how did the racket play? actually it was quite decent. i didn't find that being a cab/oval shaped racket affect the sweetspot that much. however, even though it was a 25/26lb stringing, since it is PT, i find that the resulting tension was way too low. perhaps i was being too agressive with lowering 1lb per string after the center few mains string. i calculated the effective tension averaged out across the string bed is only 22lbs. that compared to the 24-26lbs that i am normally accustomed to, i didn't like it that much. the bouncy string bed is not very good for touch shots like net shots.

Kwun,
if you think sitting on the shelf would have let the tensions equalise, how could the tension differences have survived the stringing process?

1lb per string may well be too much of a decrement.
What string did you use?

Originally posted by bigredlemon
Didn't you also tell us a story a few months (last year) in which a friend of yours could tell the tension of the racquet by merely hearing the tone it made when it cleared a bird?If you can find that story, I'd also like to see it!! I've not heard many people make that claim. If you are using that claim to doubt the validity of my information, I can even tell you who the players are. I do admit asking the question 1 year ago. But the answers I got were quite unexpected and therefore stuck in my memory. If you want, I can ring them up to confirm the information since their phone numbers are in my cellphone sim card. I simply do not state their names because I think it would impolite to do so without their permission. I'd have to ring them up soon before they fly off to B'ham, England for the World Championships.

Fatigue problems are irrelavant anyway becauses it's inherently factored into the calculation. Is that true even if the rate of increase of fatigue changes and if people get a "2nd wind"?

i was under the impression that pros already prefer PT and use that method almost exclusively. Though at 30+lb, they don't have much of a choice either. Even if CT is better, pros have to use PT because their racquets can't handle CT at those tensions.we can actually go back to OT23Lok's statement here. And remember OT23Lok's also states that they have a lot of experience stringing for pros at grand prix events and TC/UC.
It makes no harm to your racket and it's a good way to raise the tension a bit, but when we're stringing for the pros, even for 10 years ago, we're using the 6 points protection machine and stringing at Full over-tension up to 32 pounds.
In fact, I doubt very much that many pros ask their stringer to use PT, but it would take a survey. The use of PT seems to depend on two very important factors. That's if the stringing is done with a 2 point machine and the stringer. If we go back to the article that Kwun managed to find the Jens Eriksen's stringer uses PT, BUT, the type of stringing machine used was not stated.

BRL, another question.
In your round robin test, what would happen if there was a player who couldn't play well enough to get any points. It wouldn't make any difference if the player uses PT or CT since he/she wouldn't be able to hit the shuttle. The points scored would be zero. Would that increase the need for more games?

And I think we didn't resolve the issue of increased playability of strings having a direct relationship with points scored.

Another point is there seems to be no agreed standard for PT, everybody seems to be using a slightly different variation.

Kwun's statment about the strings not moving after a couple of weeks is something I suspected. The experiment will need freshly strung racquets. Translating to the real world, only the pros get the luxury of stringing with a freshly strung racquet. In fact, the racquet might 'sit around' for a few hours before being used therefore having string movement. And again, for us poor amateurs who are convinced that PT holds benefits ie Pete, BRL (and possibly Kwun, now perhaps on the fence), it seems that any benefit, if present, is already negated a couple of days after the stringing process once the stringing tension has equalised.

Neil, I think asking what string Kwun used is irrelevant to this argument since we are arguing on the relative merits of PT vs CT. As long as the string was the same, and I'm sure that Kwun used the same string in both racquets. Settling and movement of the strings to 'equalisation' will be a function of time and a constant for each string. There are many unresolved issues like this. That's why having a stringing machine at hand to conduct this sort of experiment is invaluable for immediate evaluation. I know Cooler is a stringer and has conducted many 'in-house' experiments. I wouldn't be surprised if he has already performed this part of the investigation.

Cooler said
I have asked one MS silver medalist what tension he uses, he said 29 lb, i ask why, he said that was the tension of his racket when he started playing badminton when he was a kid. Is that Cheah Soon Kit?

Cheung, I was asking which string Kwun used because I was in the middle of trying to decide in my head if the guage of string would alter how we might want to reduce tension on the outer strings. (and if it was a slippery Ti string)
Since that post, I think I've decided the string guage is irrelevent, it is only the length of the outer strings we need consider

Kwun's request would have meant the tensions were
main 25,25,25,24,23,22,21,20,19,18,17
cross 26,26,26,26,25,24,23,22,21,20,19
(from the middle outwards)

For an ISO head, based on the string lengths I would guess
main 25,25,25,24.5,23.9,22.8,21.7,20.1,18.5,16.3,13.6
cross 26,25.7,25.4,25,24.3,23.6,22.7,21.4,20.2,18.1,16.4
would give a more even (for want of a better word) stringbed

obviously, that would be a right pain to string
so maybe (if we assume the outer 4 are much less relevant, because if we hit it there you're not going to play a good shot anyway)
main 25,25,25,24,24,23,23,23,23,23,23
cross 26,26,26,25,25,24,23,23,23,23,23
would be a reasonable compromise

If we keep the outer strings higher than what theory might suggest, it might help prevent the strings creeping.

and from what Cheung said earlier
Bumped into luxis today and asked him what he strings at using the high tensions
1) first check the racquet is suitable for high tensions
2) mains - middle ten strings at the tension, rest of strings 2 lbs lower
3) cross - middle ten strings 2 lbs higher than mains, reduce by 2lbs for top and bottom.

that may well be the case


P.S.
I read this on the British Harpsichord Society's webpage (of all places)
The proportion between extension and tension is linear, but the proportion between tension and pitch is logarithmic.

If you double the tension, the string stretches twice as mutch, but to double the pitch you have to increase the tension by more than double.
So keeping a constant pitch when you pluck the strings across the stringbed isn't necessarily what we're after.

Kwun,
you think the fact that the strings didn't shift could be because that the cab 20 doesn't have mp features? Like i said before, the MP bumps allows the string slide more loosely. Without those bumps, the string is held much more tightly in place and hence isn't able to move as freely.

Also possible that the stringer didn't stringing it properly such that it was already almost CT when you got it?

Originally posted by Cheung
If you can find that story, I'd also like to see it!! I've not heard many people make that claim. If you are using that claim to doubt the validity of my information, I can even tell you who the players are. I do admit asking the question 1 year ago. But the answers I got were quite unexpected and therefore stuck in my memory. If you want, I can ring them up to confirm the information since their phone numbers are in my cellphone sim card. I simply do not state their names because I think it would impolite to do so without their permission. I'd have to ring them up soon before they fly off to B'ham, England for the World Championships.

I don't doubt your story Cheung, I'm sure it's quite possible. As you said though, you yourself was surprised by the answers, which suggest that the players involved were unusual. I suspect the majority of players of their caliber would indeed know the tension. I used the finger-grip method you showed me (the Gade one). When I use that grip to execute a tumble shot or net drop, the bird hitting the string bed creates a unique vibration. Given identical racquets and strings, I think it would be easy to determine different tensions under those conditions.

Also I did a search for the story i said you said and did not find anything (by anyone actually.) I know it was said on this board, and I think it was you, though i could be mistaken so sorry if I misattributed that quote to you. From what I remember, it was said between Novemeber and January.




Is that true even if the rate of increase of fatigue changes and if people get a "2nd wind"?

If they do get a second wind, then it would show us as though there were always that good since there are only 3 datapoints. If there were more, a regression analysis could be used to determine the true rate of fatigue but I suspect that method was involve more math than I care for, espically if that fatigue rate is non-linear. I'll just throw that factor into the error box. People who get PT are no more and no less likely to get a 2nd wind than players with CT racquets, so there would be no problem in ignoring it altogether.


we can actually go back to OT23Lok's statement here. And remember OT23Lok's also states that they have a lot of experience stringing for pros at grand prix events and TC/UC.

In fact, I doubt very much that many pros ask their stringer to use PT, but it would take a survey. The use of PT seems to depend on two very important factors. That's if the stringing is done with a 2 point machine and the stringer. If we go back to the article that Kwun managed to find the Jens Eriksen's stringer uses PT, BUT, the type of stringing machine used was not stated.

I standed correct on that matter then. The extent pros use PT is unclear.

BRL, another question.
In your round robin test, what would happen if there was a player who couldn't play well enough to get any points. It wouldn't make any difference if the player uses PT or CT since he/she wouldn't be able to hit the shuttle. The points scored would be zero. Would that increase the need for more games?

No that would not matter. I'm looking at the difference between actual and expected. It is irrelavant how many points they score. It only matters what the point spreads are. That's actually a weakness of the test that I forgot to consider.

If a player is bad enough, he would be expected to have negative score. I.e. Suppose CT players tend to get 1 extra point on average. A horrible player always loses 0-15 with CT. When he gets a PT, the test would expect him to get -1 point. This isn't possible in badminton. This problem is only hypothetical though because we don't expect that situation to come up often. I remember using this test on a population of fish lengths and almost 4% of the fish had negative sizes. We just change those values to zero and the test worked out fine anyway.

If a player does get a 15-0 score, then that adds to the error and shouldn't be considered fatal to the test or anything.


And I think we didn't resolve the issue of increased playability of strings having a direct relationship with points scored.

The test i propose tests the effects of the string on your score. Afterall, that is what we care about right?

Even if there's a new magic string that allows you to hit 10x faster harder quicker and more accurately, but has no effect on whether one wins or loses a game, then that string isn't that great is it?




Another point is there seems to be no agreed standard for PT, everybody seems to be using a slightly different variation.

I'll only be testing whichever standard is used in these games, which is all that could be tested.



Kwun's statment about the strings not moving after a couple of weeks is something I suspected. The experiment will need freshly strung racquets. Translating to the real world, only the pros get the luxury of stringing with a freshly strung racquet. In fact, the racquet might 'sit around' for a few hours before being used therefore having string movement. And again, for us poor amateurs who are convinced that PT holds benefits ie Pete, BRL (and possibly Kwun, now perhaps on the fence), it seems that any benefit, if present, is already negated a couple of days after the stringing process once the stringing tension has equalised.

As I said the test focuses on real world conditions. If the string can't even show any effect after only a few hours of play, then surely it isn't the magic bullet we thought it was!


Neil, I think asking what string Kwun used is irrelevant to this argument since we are arguing on the relative merits of PT vs CT. As long as the string was the same, and I'm sure that Kwun used the same string in both racquets. Settling and movement of the strings to 'equalisation' will be a function of time and a constant for each string. There are many unresolved issues like this. That's why having a stringing machine at hand to conduct this sort of experiment is invaluable for immediate evaluation. I know Cooler is a stringer and has conducted many 'in-house' experiments. I wouldn't be surprised if he has already performed this part of the investigation.

Hmm... maybe cooler can perform this experiment for us? :)
String a racquet with PT, then market the lines right after tying the knot. Wait a day and see if the lines moved. If it did, remark the lines with a different color and go play! See where the lines are afterwards. I guess it would be important to note if you used an mp or non-mp racquet.

Using a spare badminton string of the same type, attack it to some high fixed object like a doorframe. Longer string is better of course. Attack a hook to the other end. Or you could tell it to a notebook ring if it's more convient. Attach the bottom end of the string with a light object, like a half empty bottle of coke so that the line is taught. Measure the length of the string that is being stretched. Now add a 10kg mass to the bottom and measure the string length again.

This test doesn't sound too difficult?

With those values, (elasticity of string and string movement) it would be possible to know the actual tension of the different sections of the racquet. We can tell how much it stabalizes or if it completely turns into CT after a few hours or a few games.

Cooler said
Is that Cheah Soon Kit?
I don't know?

Originally posted by Neil Nicholls
If you double the tension, the string stretches twice as mutch, but to double the pitch you have to increase the tension by more than double.
So keeping a constant pitch when you pluck the strings across the stringbed isn't necessarily what we're after.
Are you sure it said the pitch change is logrithmic?
The tone/pitch should be linearly proportional in terms of physics, but since are human ears operate logrithmically, that doubling of vibrational wavelength would be percieved as being a mere 30% increase rather than a full 100%. (log2=0.3, log1=0).

If you do mean the actual pitch is logrithmacally changed, then the percieved tone would have to change to the square of the log.

a few bad examples in the list bad i think you understood my gist. Maybe I should rephase it. Suppose all those variables do affect the game. How would that affect the result? There no logical reason for someoen who just ate dinner to be luckier and get one stringing type more often than another. Even if there is a logical reason for that to occur, then that is some property of the stringing method and hence worth the consideration anyway. You seem to suggest in your original post that I would need to know the exact values of those variables in order to get a true result. Prove it. (It's easier to contradict a proof than to make one up... esp since i havent slept in a while.)

How? well, i play terrible with a full stomach and also lousy with an empty stomach but not as worst as full stomach.

I think u needed some sleep as u are not reading my point of view. I am trying to show u that there are overwhelming variables to be filtered out before you get to see the PT vs CT data trend. Forget about knowing the exact values of the variables, dealing with the quantity of variables is tough enough.

Since you said u can use statistical data to derive any data trend/conclusion, here one for you to consider. China's Ji Xinpeng won the men MS gold medal by beating hendrawan. Ji Xinpeng never won anything big after that while Hendrawan had won several big MS title after the olymipic. From this trend, can you tell us which variable(s) explain this outcome?

quote:
--------------------------------------------------------------------------------

Cooler said
Is that Cheah Soon Kit?


no, i didn't named any name. Beside, i said MS silver medalist, CSK never won any major MS title before.

Originally posted by cooler
a few bad examples in the list bad i think you understood my gist. Maybe I should rephase it. Suppose all those variables do affect the game. How would that affect the result? There no logical reason for someoen who just ate dinner to be luckier and get one stringing type more often than another. Even if there is a logical reason for that to occur, then that is some property of the stringing method and hence worth the consideration anyway. You seem to suggest in your original post that I would need to know the exact values of those variables in order to get a true result. Prove it. (It's easier to contradict a proof than to make one up... esp since i havent slept in a while.)

How? well, i play terrible with a full stomach and also lousy with an empty stomach but not as worst as full stomach.

I think u needed some sleep as u are not reading my point of view. I am trying to show u that there are overwhelming variables to be filtered out before you get to see the PT vs CT data trend. Forget about knowing the exact values of the variables, dealing with the quantity of variables is tough enough.

Since you said u can use statistical data to derive any data trend/conclusion, here one for you to consider. China's Ji Xinpeng won the men MS gold medal by beating hendrawan. Ji Xinpeng never won anything big after that while Hendrawan had won several big MS title after the olymipic. From this trend, can you tell us which variable(s) explain this outcome?
I think you are missing my point. I have never denied tha there are other variables that would affect the outcome. What I have said was that they are irrelavant to the statistical analysis that i presented. I find it highly unlikely for all players who use PT racquets to play on an emplty stomach the first game, then decide to take a break and eat until they are full, and they continue to play while all players with CT racquets show up with full stomachs, stop after their game, and suddenly become hungry again.

Also i specifically said that i would not need to consider the other variables. Why should i care about which variables affect the outcome? They never come up in the stats analysis and are not needed. You say I do in fact need to know but have not given me any reason why I should with respect to the test. You have only given me examples of those variables having some effect, which i have never denied in the first place.

Let me put this another way:
Each time a big variable swings in favour of one stringing type, there is an equal chance that it would swing in favour of the other stringing type in another game. The two events cancel out. Hence, I need not consider that variable.

.................................................. .........................................

My reasoning is based upon the assumption that your reasoning has always been this:
- there are variables with big effects
- the effects of the variables cannot be determined
- Conclusion: the stats test will fail because the effects of the unknown variables is greater than the effects of the known variables.

My rebuttle: your reasoning is flawed in that it presumes the unknown variables's effects are consistent.
My reasoning: you presume that the effects of the unknown will correlate with the stringing type on the one hand and yet remain unrelated to the stringing type. These two situations cannot coexist.

So my summary of my summary:
You make two assertions that, if true, would make the test ineffective.
Those two assertions cannot be true simultaenously.


I'm summarizing our reasonings because the discussion is quite long and it appears one or both of us are missing the forrest for the trees.

Bigredlemon :
i was under the impression that pros already prefer PT and use that method almost exclusively. Though at 30+lb, they don't have much of a choice either. Even if CT is better, pros have to use PT because their racquets can't handle CT at those tensions.

Cheung :
we can actually go back to OT23Lok's statement here. And remember OT23Lok's also states that they have a lot of experience stringing for pros at grand prix events and TC/UC.


Yes there is a lot of experience using PT for the pro's, but judging from the statements, it is performed in a perspective of not breaking the racket rather than from the point of playability.
It is suspicious that PT wasn't discovered as being very playable though. But my point of view was and still is, that if some tests of us amateurs may define PT as more playable than CT, it might be worth for further testing by pros with better playability as goal in mind.
And yes of course it is very possible (and likely) that this has been tested by them with that in mind before...

Originally posted by kwun
so here is the story. i brought my rackets to my stringer 2 weeks ago saturday. and i told him that i will pick them up tuesday. being so diligent that my stringer was, he had them all strung and left on the shelf on sunday. the racket sat there for two days before i pick them up. i think what happened during those two days was that they already gone through the shifting. and i marked the string too late therefore i didn't see any shifting at all.


Ah, disappoiting results, too bad !
But wow, also no shifting ! I don't think you would have seen the markings shift if you marked the strings right after stringing.
In my case, during the string-marking test, i marked the main strings while stringing the racket, right after pulling the next or second next main string. The cross strings were marked right after knotting off. No shifting during the stringing process, no shifting in the first 4 days the racket was in rest. After +- 12 hours of playing, still very little, no significant shifting.

so how did the racket play? actually it was quite decent. i didn't find that being a cab/oval shaped racket affect the sweetspot that much. however, even though it was a 25/26lb stringing, since it is PT, i find that the resulting tension was way too low. perhaps i was being too agressive with lowering 1lb per string after the center few mains string. i calculated the effective tension averaged out across the string bed is only 22lbs. that compared to the 24-26lbs that i am normally accustomed to, i didn't like it that much. the bouncy string bed is not very good for touch shots like net shots.

since kwun and yong didn't see any noticable string movement (tension equalization), I'm puzzled why kwun can detect or feel overall lower racquet tension, assuming kwun hits the shuttle at the sweetspot and in PT case, the sweetspot is made up of strings of 25/26 lbs tension.

When i do my hybrid stringing, i don't lower by 1 lb increment. I don't see the curvature of the racquet corresponds 1 lbs per row/column of grommet. My techinque sounds similar to luxis, i just drop to X lb after finishing the core pattern. It's much simpler to keep track and u still need decent tension to balance the stress of the overall racket.

Originally posted by bigredlemon
The test i propose tests the effects of the string on your score. Afterall, that is what we care about right?

Even if there's a new magic string that allows you to hit 10x faster harder quicker and more accurately, but has no effect on whether one wins or loses a game, then that string isn't that great is it?

Of course we would like to think increased playability = more points. I'm just saying the relationship is not exactly there for a small thing like PT.

Maybe an analogous situation is if you had two cars, A & B. B has better suspension, better turning stability but if I drive both of them at 30kph all the time, I would still travel between two points in the same amount of time.

Originally posted by Cheung
Of course we would like to think increased playability = more points. I'm just saying the relationship is not exactly there for a small thing like PT.

Maybe an analogous situation is if you had two cars, A & B. B has better suspension, better turning stability but if I drive both of them at 30kph all the time, I would still travel between two points in the same amount of time.
Well, the goal of badminton is to score points right? Otherwise, i'm sure people would perform more trick shots like ones Gade does to show at the cost of a few points or smash hard for the fun of it when a drop would have been better. Maybe they do sometimes, but points is what people are usually after.

If in your example they were race cars, like dragsters, then all the extra suspensions and such doesn't affect the performance and is uneeded. Those dragsters tend to have horrible turning stability anyway. So the test to be used have to correlate with the actual goal. For a formula-one race car, a drag race test would be incomplete. A game of badminton however, is a complete test of how well its use would be in a game of badminton... or at least more so than simply hitting birds a few times to see how it feels (that would analogous to using race cars on a drag race.) I think you argued against your own test Cheung!!

BRL,
Let's go away from racecars as they are very specialised peieces of equipment. The point is that for ordinary cars, driven at 30kph, there isn't much difference at end result fro the example I gave.

Yes, the point is to score more points in badminton. But playability doesn't mean getting more points. How many people do you know who change their racquets and have a wonderful increase in the number of points they get because of better playability? In the end, it comes down to personal preference. PT vs CT is the same except we have stringer and stringing equipment considerations.

I've played singles with an ex-HK player (ex-China) province. I've never been able to get more than a few points off him. The only way I will win is if I break his leg with my racquet or stab one of his leg muscles with the broken shaft of my racquet. I doubt a racquet strung with PT will help much becasue he's so fast around the court, I can;t get to the shuttle very well to get a good contact and play a good enough quality shot. Even if I do play a good shot, he nearly always plays a good quality shot back which I can't reach. For a realistic game. I can only get more points if I improve my speed, and imporve my consistency - that takes training, not stringing PT.

That's why I suggested the standardised test for a range of shots in a double blind manner. This tests only the feel. We eliminate most of the other variables that people would tend to say impinge on the test. It's simple to understand for the layman. We wouldn;t need to argue with everybody 2 pages on statistics to justify the test. Why use a test which people intuitively have doubts on compared to a simple test?


Cooler's suggestion of a mechanical swing removes the human subjectiveness. I also support that because it gives data that everybody can understand and interpret. I'm not saying that your test won't work. we might not see the difference early on. And the variables involved are actual points, not playability. I would say the next stage after my test is your experiment.

That's also a point where Cooler's mechanical swing falls down on. Playability of strings is essentially a human opinion on the impact of the shuttle on the strings. Wether the shuttle flies to where you want it to go is another matter. The mechanical swing can give us hard data, yes. As you know, human opinion can be opposite to hard data.

sorry for the shortened post. My baby is acting up

cheung, that is why is I had included both mechanical and human testing of PT vs CT. A machine test measures one variable at a time where as human can evaluate multiple variables (playability) simultaneously but playability is subjective depending on skills and past experience of that player.

Take a chapter from golf, which is also a very technical oriented sports. Every golf magazines have instructions to tell the reader how to swing a club, in every issue since the first golf magazine. In golf, you'll see clubs and balls are mechnanically tested although it give one dimensional results. If we just looking for any advantage of repulsion & control between PT vs CT question, i think machine testing can provide answers to that but will never tell you how it feel or its playability. That is where human testing required for this parameter. If i play badminton for 20 years using CT method, changing to PT would degrade my game although it might help others. That is why using game score results to indirectly derive subtle differences between PT and CT is realistically impossible (unlessl one has data from many many games). Statistical method advocated by BRL works fine in paper and theory but not in the real world.

*sigh* unfortunately, life is not black and white.
There are cases where PT (progressive tension) give the desired benefits, depending what kind of benefit the user want it to be. The agrument presented by kwun is very convincing but that is for initial condition. If one string it perfectly using PT, that's great initially. However, when the strings start to equalizing their tension over time, the stress get re-distributed, hence, re-shaping the frame shape, although too small for the eyes to notice as frame shape changes progressively. Overall tho, a 28x28 racket will alway be more stressful than a 28 PT because on average, PT at 28 is not really 28 but average out around 24-25 lb, assuming the edge tension was initially 20 lb.

kwun, for those cases u mention that most racket u saw having distorted sides. True but i think that has to do with poor stringing technique. Most stringers follow top down for cross so the top half get squeezed. I don't follow the so call yonex prescribed method so i don't have those problem.

To sum things up, i think there is benefit of PT stringing but only in unique situation and the benefit is temporary (if one use modern racket and string) . Maintaining and controlling the racket shape during stringing is much more important in minimizing stress and strain on the frame. If anyone restring their racquet as frequently as pros, then go for PT.

yup........ so true.

sorry havent finished reading all (up to page 5 now) but fell i got to support this b4 i forget where it is

cheers

after going thru 11 pages of this thread. this is my stand on PT

1) using this method i would most prob need to use the 10% diff incremental on the crosses to maintain the shape compared to CT.

2) i agree that it is a 'fake tension' and wouldnt last 'long'.

3) i feel that to many players are playing at tensions too high for their own good. im not saying that they cant handle it, but it is over their optimum tension. most prob psychological.

4) no comment on how to test PT vs CT.

5) time consuming........

6) im not taken over by claims of 'wider sweet spot' using PT. just my opinion

7) IMHO, the root of this argument is becoz most of you are using racquets strung from the center for the mains and are experiencing 'running' center mains............. hahahaha.
but of course method is only part of the solution


disclaimer: being a commercial stringer (where time equals money) it can also be assumed that my negative views againts PT is bias....... hahaha

Hi Grufey,

Badrad used to do progressive stringing method but he no longer bothered to. So, I guess you have to go to HK and ask Mr. Ng of Luxis to do it for you ;) .


im very interested on the reason why Badrad no longer 'bothers' to practice PT.

the only possible conclusions that i can think of are the following;
1) the monetary incentive does not justify the effort/time put in
or
2) he finds that it is a 'fake tension'
or
3) he feels that the effort that he puts into the process of PT goes unappreciated
or
4) the diff is insignificant
or
5) it doesnt matter what tension/method of stringing he gives you, on court he'll still own you.


im going to PM Badrad and see if he can facilitate us with the answer. :D

im very interested on the reason why Badrad no longer 'bothers' to practice PT.
'''
'''
im going to PM Badrad and see if he can facilitate us with the answer. :Dokay - i'm here...
for PT - i simply stopped doing it because it really doesn't matter all that much. this is a technique/skill that you as a stringer may prefer if you have the time and the ability to do it.

but over time, you'll find that this debate is much like having a couple of cooks arguing over whether one should give a hamburger patty an extra 1/4 twist to give the patty an nice set of grill marks... it takes a second or two extra, but it quickly gets covered up with the condiments, trimmings and bun, that the effort will be lost to the customer. (take note that I am not comparing charcoal grilling to pan-fry).

the customer only wants a burger - how the cook makes it (as long as it is good, tasty and safe) really doesn't matter all that much to most consumers.

so for those cooks who still want to grill burgers with grill marks - make the burger open face - then the consumer wll see the effort taken...

hey badrad, nice to see u r still surfing here, albeit in semi cloaking mode :D

Let me add one more reason of why PT is no longer popular

That is:

Assuming that the virtues of PT are all true, how can one be assured that players get this special stringer all the time. For pros, if there ask for PT stringing from the tournament stringers, they'll laugh at him/her. (at risk of not getting his or her autograph too :p ) Same as if one loved hamburgeer from one particular restaurant and then one day he goes to McDonald and ask for medium rare beef burger with low Sodium low fat special sauces and whole wheat buns. Ie, repeatibility can't be achieved for PT stringing outside your regular stringer. Only solution is learn and string your own racket. However, that is not a guaranteed successful option.

i just really want to thank badrad for answering this request. im happy that we share the same views on PT, but i would still be happy otherwise as well.
its just nice to hear from another stringer.

happy trails :)

i just really want to thank badrad for answering this request. im happy that we share the same views on PT, but i would still be happy otherwise as well.
its just nice to hear from another stringer.

happy trails :)
hmm, i thot your general comments were that u don't fundamentally believe in PT's benefits where as in Badrad's case he stop doing PT because his clients don't appreciate or notice his effort, quite a different reason although u both dont use PT. :rolleyes: :D

If a player wants his or her racquet strung the PT method, so be it. Some players may actually prefer PT, just like some prefer very high tension. Who are we to question them?
However, a proper PT stringing job should start stringing from the middle for both the cross and main strings. This ensures better tension integrity of the higher tension of the middle cross and main strings. Also, you should come clean and advise the customer that PT stringing does stress the four corners of the racquet frame more than the Yonex recommended pattern. :p

If a player wants his or her racquet strung the PT method, so be it. Some players may actually prefer PT, just like some prefer very high tension. Who are we to question them?

Also, you should come clean and advise the customer that PT stringing does stress the four corners of the racquet frame more than the Yonex recommended pattern. :p

I'll go with your first statement ' Who are we to question them?'
because your second statement is in conflict of interest with the 1st plus that imo your 2nd statment is not accurate.

I'll go with your first statement ' Who are we to question them?'
because your second statement is in conflict of interest with the 1st plus that imo your 2nd statment is not accurate.

It is not the type of "conflict of interest" which is generally frowned upon, but more like a "let the buyers beware" information which I feel morally obliged to offer. You have a right to your opinion on my "2nd statement is not accurate", which is obviously different to that of mine. ;) :D

taneepak. let's see if we can persuade you to change your opinion... :)

in post #66 of this thread, the link is provided here:

http://www.badmintoncentral.com/forums/showthread.php?t=8079&page=4&pp=18

i have outlined why PT puts less stress on the badminton frame's 4 corners. perhaps you can give that a thought.

I have brought up this proportional stringing method with Yonex and asked them for their opinion. After several days, Yonex responded with a very diplomatic reply. They did not offer any comment on proportional stringing, but reminded me to follow the Yonex pattern!
BTW, has anybody strung a racquet without any side strings on the mains and crosses? ;)

Confusious says, go easy and move along with your chi....ie. gut feeling and the tune you fell its good.
rgds

hello guys,

i have the some question about racket stringing methods...

should the vertical & horizontal string tension be the same for optimum performance or it is just purely for preservation of racket shape?

as my armortec tensioning specs are from 20 - 25 lbs...currently stringed at 23 lbs.

but i read from an article saying that horizontal stringing tension should be 22 - 25 lbs & vertical tensions 20 - 23 lbs.

pls advise.

thank you.

Epiphany: How does the string bed look like at max stretch?

1. PT:
* *
* *
* *
* *
*

2. Constant Tension

* *
* *
* *
* *
*

The illustrations show how both string beds ought to look like after equalizing. PT allows the outer strings to stretch more than with CT. PT would allow the racket to cheat death a little longer by having less stress at the corners while still achieving peak warranty-voiding stringing tensions. Neither technique would show any significant advantage if the player hits at the center all (most) of the time.

Please note that I have only been stringing for 5 years and I am not a certified stringer. But, I obsess over badminton stringing.

Here's a mind bender: Combine Newton's 2nd Law of motion with Hooke's Law given mass of the racket, string, (approx) player's forearm, and the player's swing speed, while equilibrium (string tension) is the variable.

Enough said.

I've strung my racket several times like this, and the feeling is amazing at first, but after some serious pounding, the tension just evens out. Is there any way to lock in the tension of how it was originally strung? Orthodox or unorthodox ways?

taneepak. let's see if we can persuade you to change your opinion... :)

in post #66 of this thread, the link is provided here:

http://www.badmintoncentral.com/forums/showthread.php?t=8079&page=4&pp=18

i have outlined why PT puts less stress on the badminton frame's 4 corners. perhaps you can give that a thought.

Not sure how long this post has been here for, but when I read the link you posted, I kinda disagree.

RE:

"not sure if you have seen this, but i have seen it on many racket, esp cab rackets. after stringing at high tension of 25+ lbs, we find the the corners of the rackets get squeezed in. and now i believe this is exactly the reason, that uniform stringing is pulling on the racket frame non-uniformly.

if you have followed my argument this far, then i think you can probably deduce the rest. with progressive stringing, we are actually lowering the tension as we move towards the corner of the racket, cancelling out the 2 x sine(45) extra force acting on the racket. as a result, there is now less stress on the racket frame.

i hope this makes sense."

I believe the 25 lbs on the mains also puts an outward horizontal force on the frame, which you did not account for. I really don't think this can be solved by such simple math as there are many variables involved. A racket may still be under stress even if there is no frame deformation.

I suppose it wont matter as long as the customer is happy with your stringing and you dont try to intentionally break their rackets.

Interesting thread tho.

moderators, sorry please kindly remove, thanks.

i have seen this method used by a couple of good stringer. i have watched Emmy's father and Luxis (Mr. Ng) string, and they both lower tension as they move away from the center string. the result of Luxis stringing is one of the best i have seen. there is a certain repel coming from the string that feels very nice. i can't vouch for Emmy's father stringing as i have never tried it.

as for how many pounds to lower, i don't know. perhaps someone should pick Luxis' brain for it.

as for why and how this method works. the first observation is that the repulsive power from a racket is determined by the natural frequency of the string. strings with different natural oscillation frequency will react differently when struck. the natural frequency of the string is determined by a few factors, the length of the string, the tension of the string, the thickness&material of the string.

given that fact, also observe that the length of the middle string and outer strings are different. thus, if strung at exactly the same tension, the outer string will have a higher oscillation frequency than the center strings, thus creating a string bed with uneven repulsion. i believe this will make the sweetspot smaller and if overly done, will make the racket feel very "dead".

lowering the tension of the outer string will cause the tension across the string bed to be more even and thus enlarging the sweetspot and make the racket more alive.

i don't believe many stringers knows about this fact. and it is for this one reason that i am considering re-purchasing a stringing machine. the quality of stringing i have tried is worse than what i expected. and sending all rackets to Luxis doesn't seem to be too viable a route..... but then, i don't want a cheap drop weight machine again as they are such a pain to use. and a good crank machine is rather expensive... :(
Have you ever tried AK Badminton in Newark? He is stringing on the Yonex ES5 Protech machine. I heard people like Tony Gunawan, Halim, Grace Peng, Mona Santoso and Tennis Pro Venus Williams like his stringing. He has also stung for Andy Murray 2 time SAP Open tennis Champion.

oh, one more thing i forgot. to determine how many pounds of tension to lower, this is one way to determine it.

after you are done with the main strings, pluck the strings and listen to the tone. or just pluck across the string bed. if the natural frequency is uniform, then all the strings will have the same tone.

the real experiment would be to compare rackets with different tones, try strining one with lowering tone center->side, string one with uniform tone, string one with rising tone, and see which one plays better.

surely, some master stringer somewhere must have figured all these out already.

I think for master stringers it just adds too much time on rackets, when you are at the world championships and there are over 700 rackets to string (just guessing from 2005) changing tension constantaly just adds up. Watching the England stringers string about 14 minutes a racket and the Americans at about 18, adding extra time, and since the top players are just happy to get their rackets back, why change something that aint broke?

Tried the 'lowering tension' method on 2 stringing jobs and i am pleasently surprised about the results.

Main tension : 26 lbs for the middle 4 strings. Tension was lowered on each next string, ending with 20 lbs for the outer strings.
Cross tension : used 2 tensions : 25 for the middle, 23 for the 5 top and 5 bottom strings.
Cross sring was done top to bottom. Want to try from strining from center some time, but with my 2 current swivel clamps, this is impossible, at least, when tensioning every string.
Stringing job was done on a 6-point crank machine.

Compared to the previous one-tension stringing jobs on the same racket (also done by myself), the racket absolutely felt more alive. During play, smashes were harder while control still felt good.
For badminton should string bottom to top. The top of the frame is stronger, because if you impact a racket, hitting another racket or hitting a bird, is more stronger. there is less frame on the top to break and more frame on the bottom to break. Yonex recommends to go bottom to top, as well as the 2009 Pan American string team. At the 2005 World Championships I heard a stringer was stringing top to bottom. Stringing a players racket at 34 pounds broke 3 frames in a row. did bottom to top and didnt break any thereafter. One of my friends told me that.

oh, one more thing i forgot. to determine how many pounds of tension to lower, this is one way to determine it.

after you are done with the main strings, pluck the strings and listen to the tone. or just pluck across the string bed. if the natural frequency is uniform, then all the strings will have the same tone.

the real experiment would be to compare rackets with different tones, try strining one with lowering tone center->side, string one with uniform tone, string one with rising tone, and see which one plays better.

surely, some master stringer somewhere must have figured all these out already.
Just out of curiosity, if you "PLUCK" a 12" string pulled at 25 pounds and a 8" string at the same tension, should it not sound the same? they are both 25 pounds, the CONSISTANT same tension, why would you want to match the pitch of the strings (lower the shorter string tension)? Isn't that inconsistant? Yo I am down with experimenting, gotta find a club and players willing to playtest. I think I know a stringer with the Yonex ES5 Protech (The only one in Nor Cal for the moment) and he could probably get a couple of Arcsaber Z Slashes to string.

the solution then, is to lower the tension as you move outwards. the lower tension plus the short length on the outer string segments will produce similar resonance frequency and thus increases the sweet spot. and that's what you felt with Mr. Ng's stringing, in which i also agree is excellent.

Out of curiousity, have you ever had AK Badminton in Newark string your racket? Just curious how he rates among stringers you know, I am sure he would hook you up if you told him you wanted to critic his stringing. I could put a good word in for you. :cool:

Just out of curiosity, if you "PLUCK" a 12" string pulled at 25 pounds and a 8" string at the same tension, should it not sound the same?

if they are the same length, then they should sound the same. however, if they are of different length, then they won't. the tone of vibration is governed by a few factors:

- the length of the string
- the tension of the string
- the thickness of the string
- the material of the string.

it should be very easy to see that. after you finish stringing the main string of a racket, with all the string at the same tension as provided by your machine, then just glide your finger across the string bed (like playing a harp). you will find that the shorter string has higher tone than the longer strings.

kakinami (and all other stringers that may entertain my query, tks to all),

slightly off topic, would you string your tennis racquets like this, below? many thanks.
http://i918.photobucket.com/albums/ad29/MetalOrange/DSC00027.jpg?t=1258659652


cheers,
MetalOrange

kakinami (and all other stringers that may entertain my query, tks to all),

slightly off topic, would you string your tennis racquets like this, below? many thanks.
http://i918.photobucket.com/albums/ad29/MetalOrange/DSC00027.jpg?t=1258659652


cheers,
MetalOrange
Unfortunately Tennis rackets have 1 string pattern can't alter string pattern, i.e.skip a cross, I will let you in on a little secret, if you want to start your cross on 8, before you pull your last main (if you do #9-#12-#10 pattern) before you put in last main (#10), preweave 3 crosses (#8, #9, #10, then you can tie mains on #9 putting 3 pieces of string in #9.
Do you string bottom up? Why tie cross on 14H? that is a possiable 4X more tension loss on your last cross. should just go 5H.

kakinami,

wow, that was quick and painless. tks vm.

MetalOrange