Klippermate and Jaycee Method - does it work?

[a0f6459]

I did some extensive reading, mainly on another board about the JayCee method of stringing. The steps I found were from posts by JayCee himself.

Why I was interested in his method is that he claims that your average tension immediately after stringing should be no more than 2 lbs lower than your reference tension. For example, if you set your stringer to 58 lbs, if you measure the tension immediately after taking it off the stringer, it should be no lower than about 56 lbs. I won't go into the reasoning that he says you should and can string your racket to such accuracy, but his thought process is sound in my opinion.

After stringing on my Klippermate I ALWAYS have about 7 lbs of immediate tension loss when compared to the reference pull tension. The is according to RaquetTune which I think most users of this app will agree is pretty accurate.

One variable I am curious about is that he says his Swingway Clamps on top of his methods are the reason he can string so accurately.

So I have two questions:

1) Has anyone successfully used the JayCee method on their Klippermate?
2) Will the Klippermate clamps prevent me from ever being able to achieve his type of accuracy?

I'll post of a summary of his method in the next post.

 

[a0f6459]

For the purpose of this example I will use a 16 x 19 racket and a 2 piece synthetic gut job. He states that the crosses in this case should be 4 lbs highers than the mains. (again he has reasoning for this but I won't go into that)

58 lbs reference tension

Mains

1) 6 center mains - pull at 58 lbs
2) Next 3 mains on each side of the 6 center mains - pull at 54 lbs
3) Final 2 mains on each side - pull at 62 lbs

* press the center of each string starting from the outside mains to the center mains, pressing both the right and left at the same time

Crosses

1) 1st 3 crosses - pull 62 lbs
2) Cross 4 through 17 - pull 58 lbs
3) 18 and 19 cross - pull 66 lbs


This supposedly should all come out to 56 - 58 lbs actual tension after the racket is immediately taken off the stringer.

Thoughts?

 

[Purist]

I did some extensive reading, mainly on another board about the JayCee method of stringing. The steps I found were from posts by JayCee himself.

Why I was interested in his method is that he claims that your average tension immediately after stringing should be no more than 2 lbs lower than your reference tension. For example, if you set your stringer to 58 lbs, if you measure the tension immediately after taking it off the stringer, it should be no lower than about 56 lbs. I won't go into the reasoning that he says you should and can string your racket to such accuracy, but his thought process is sound in my opinion.

After stringing on my Klippermate I ALWAYS have about 7 lbs of immediate tension loss when compared to the reference pull tension. The is according to RaquetTune which I think most users of this app will agree is pretty accurate.

One variable I am curious about is that he says his Swingway Clamps on top of his methods are the reason he can string so accurately.

So I have two questions:

1) Has anyone successfully used the JayCee method on their Klippermate?
2) Will the Klippermate clamps prevent me from ever being able to achieve his type of accuracy?

I'll post of a summary of his method in the next post.

Interesting. I have learned a great deal reading his stuff on the internet and think he is a stringing guru, but I don't remember him saying this. Can you find this quote? I think what he said regarding the 2 pound of tension loss is only comparing amongst one device over time. AKA, the tension lets say 1 hour after your string job and then the next day. Both of these tensions are taken with some device that you trust. I doubt he would say that one can compare the reference tension on a stringer to some device after the string job.

 

[Purist]

Shoot - also, did you use the Stringway guide which takes the length of your mains and crosses into account to come up with the four pound differential? I used it and it said to string my crosses 1 pound tighter. I can verify this may be useful as I got this backward (mains one pound tighter than the crosses) and it came off of the supports tight. I also verified this by measuring the frame dimensions before and after the string job.

 

[a0f6459]

Interesting. I have learned a great deal reading his stuff on the internet and think he is a stringing guru, but I don't remember him saying this. Can you find this quote? I think what he said regarding the 2 pound of tension loss is only comparing amongst one device over time. AKA, the tension lets say 1 hour after your string job and then the next day. Both of these tensions are taken with some device that you trust. I doubt he would say that one can compare the reference tension on a stringer to some device after the string job.

See 2nd post. I also saw him mention it in other threads.


http://www.stringforum.net/board/showthread.php?t=3250

 

[a0f6459]

Shoot - also, did you use the Stringway guide which takes the length of your mains and crosses into account to come up with the four pound differential? I used it and it said to string my crosses 1 pound tighter. I can verify this may be useful as I got this backward (mains one pound tighter than the crosses) and it came off of the supports tight. I also verified this by measuring the frame dimensions before and after the string job.

I used the formula he states in this thread, post #2

http://www.stringforum.net/board/showthread.php?t=3458

 

[max]

I don't know how to put this elegantly, but I really don't give a damn if my Klippermate, at 57 pounds tension, really only delivers a real world 57 pounds. . . or 16 pounds!

MY scale of reference is the actual performance of the racquet. Macht's nicht what the number on the scale is.

 

[a0f6459]

I don't know how to put this elegantly, but I really don't give a damn if my Klippermate, at 57 pounds tension, really only delivers a real world 57 pounds. . . or 16 pounds!

MY scale of reference is the actual performance of the racquet. Macht's nicht what the number on the scale is.

Max,

I used to feel this way too until I read up on why he wanted to accomplish this.

To me it makes sense. especially when stringing up poly.

If what feels good to you is say 55 lbs in the string bed, but you need to actually pull the string at 63 to get there, you're really stretching out the string to get there. It might not make as much a difference when stringing gut, but if you had to overstretch poly that much just to get down to the tension that feels good, there is a good possibility that you will ruin the string.

This is why what he is trying to accomplish makes sense. If you could only pull the string to 57 lbs and have it settle to the 55 lbs that feels good, the string will be in much better shape.

I'm not one of those that is looking to get into a physics heady type debate, but I'm just thinking logically it makes sense.

Max, I know you use a Klippermate as well. Do you ever measure your stringbed tension vs your reference pull tension? What is your normal loss?

 

[a0f6459]

So out of all the Klippermate users out there, or any basic drop weight for that matter, no one has at least tried out the JayCee method?

 

[onefromcov]

Ive uploaded a pdf file of the jaycee method,although it is in French it is easy to follow using the pictures
http://www.filefactory.com/file/cdcd...s-volantes.pdf

 

[a0f6459]

Ive uploaded a pdf file of the jaycee method,although it is in French it is easy to follow using the pictures
http://www.filefactory.com/file/cdcd...s-volantes.pdf

Thanks, I've looked through this already and I understand the method.

I'm curious about real world application on the Klippermate. Any experience?

 

[Chas Tennis]

String Variations?

There has been a lot of attention for the stringing process and the clever measurement technique. Are the string materials important?

The results discussed must also depend on the racket and the strings as well as the stringing method.

Example Elasticity Extremes. If you strung the racket using steel strings, assuming steel is much less elastic than most racket strings, I would expect that steel would not stretch very much after applying but that very small variations in the stringing process or dimensional changes of the stressed racket might change the tension a lot. On the other extreme, if you used rubber bands the tension would probably stay the same for considerable stringing variation and dimensional changes of the racket.

If you stretch strings of different materials the elasticity of each materials will vary. Slight differences in the dimensions of the stressed racket or string length afterwards would produce different tension measurements for different materials even if the stringing was perfectly reproducible. There is also initial elasticity and some unknown elasticity fading over time.

If you can't compare the same strings and rackets at least identify each string material in the replies.

 

[Purist]

See 2nd post. I also saw him mention it in other threads.


http://www.stringforum.net/board/showthread.php?t=3250

I do understand your question. I've read everything that I can find from him on the internet (the first time I ever heard of him was in the thread from Oracle). Can you find an actual quote from him where he says that if you set your reference tension at a number it should end up as something after stringing? And what device does he say to use? I read that whole thread again and can't find anywhere that he says this.

Racquet Tune and other tools like that are useful, but only to compare string bed tension AFTER string jobs, in the same racket using the same strings, and not relative to the tension set on the stringer.

 

[a0f6459]

I do understand your question. I've read everything that I can find from him on the internet (the first time I ever heard of him was in the thread from Oracle). Can you find an actual quote from him where he says that if you set your reference tension at a number it should end up as something after stringing? And what device does he say to use? I read that whole thread again and can't find anywhere that he says this.

Racquet Tune and other tools like that are useful, but only to compare string bed tension AFTER string jobs, in the same racket using the same strings, and not relative to the tension set on the stringer.

Same post from that link

"I have explained this only so that you can be aware that the most efficient results in ball speed, comfort and playability of the strings can only be obtained when the difference between the applied tension is no higher than +2lbs when compared with the residual tension in the stringbed just after stringing. This is because the amount of elasticity in a mono-filament string is rarely attains 2% and frequently much less, or if you prefer you must try to limit the loss of tension during the string job to less than -2lbs(2% of 52lbs = 1lb, so at -2lbs the string is already suffereing from over-stretch)"

 

[a0f6459]

Later in same post he goes on to say:

"2.) If like most stringers the tension loss during stringing is from 6 to 8lbs, which means that the residual tension is about 48lbs, but this is still too tight for your son and worse than that, the string has been overstretched, most, if not all of the elasticity has been pulled out of the string. "

So he's indicating that losing 6 - 8 lbs from what you are actually pulling (reference tension), it is not acceptable.

 

[a0f6459]

RaquetTune

See post #4 of this thread

http://www.stringforum.net/board/showthread.php?t=3680

"If you can measure the average Stringbed tension (I find the iPhone app RacquetTune to be very usefull and very precise once you get the hang of it) then you have an efficient means to compare what you have in the racquet with the average ball length on the court."

Then further down

"The AST will be less than the "set tension" on the stringing machine. It is important to be able to establish the average difference between the "set tension" and the AST 1-2kgs is the usual difference, if it is more than this, you should try to improve the efficiency of your stringing."

So he is saying AST (as measured by RaquetTune) 2 - 4 lbs is the usual difference between machine tension and stringbed tension. Otherwise, learn to string better!

 

[a0f6459]

post #9 of that thread

"The Average String-bed Tension (AST) is consistantly is from 0,5kg to 1kg less than the set tension when I string with any of my 3 machines with fixed-clamps, but spot on when I string with the ML.100 with the flying-clamps (it's hard to believe, but perfectly true).

Cionsidering this difference to be normal, I always drop off 1kg for set tension on the drop-weight with flying clamps to be certain obtain the same result that I would usually get on the professional machines. (if you don't apply my stringing method then the difference will be much higher, usually a loss of 2-3kgs between the set tension and the AST)."

 

[max]

Max,

I used to feel this way too until I read up on why he wanted to accomplish this.

To me it makes sense. especially when stringing up poly.

If what feels good to you is say 55 lbs in the string bed, but you need to actually pull the string at 63 to get there, you're really stretching out the string to get there. It might not make as much a difference when stringing gut, but if you had to overstretch poly that much just to get down to the tension that feels good, there is a good possibility that you will ruin the string.

This is why what he is trying to accomplish makes sense. If you could only pull the string to 57 lbs and have it settle to the 55 lbs that feels good, the string will be in much better shape.

I'm not one of those that is looking to get into a physics heady type debate, but I'm just thinking logically it makes sense.

Max, I know you use a Klippermate as well. Do you ever measure your stringbed tension vs your reference pull tension? What is your normal loss?

A very unusual consideration, and one I had not run into, the notion of "string damage." I've tried polys and had hoped they would work for my game, but I didn't experience anything grand---perhaps you have to use a light frame to get the benefit. I'm at 349 g.

I love tennis physics. But I haven't bothered with various measurements of tension loss. I suppose I would if I were stringing my frames with two machines and wanted equivalent results. But I'm tuned into what my Kmate does, so the ostensible "57" it pulls is just right for me. (I know from past sad experience that various machines will vary, and that's one reason why I bought my own machine.)

 

[Purist]

Ahhh, I stand corrected. My first concern about you not getting the number that you expect is with Racquet Tune. Isn't it dependent on string type and thickness (I had it on my former phone and used it too)? Seems like there would be too much variance with this.

Secondly, did I miss anywhere on this page where you mention how long you let the string be pulled? I think I remember him saying at least 5 seconds with a drop weight. This would be the single most important factor in trying to achieve this. Also, as your string stretches, doesn't the weight go past horizontal and it's no longer pulling at the set tension?

I absolutely agree with what he says about string elasticity. This of his analogy to a ball point pen spring, especially for a poly. I have a lock out crank machine and do the following things to help remove some elongation:

1. Pull very slowly on the first pull
2. After the brake locks out, I move the clamp (but don't close it)
3. I then pull slowly again, and try to pull at right near the set tension (by watching the brake release doo-hickey) for at least five seconds. I then clamp the string.

After using this technique, I have found that I need to string much looser (6 to 8 pounds) than I used to and the string bed tension seems to be stable for a longer period of time.

 

[Purist]

snip...

After stringing on my Klippermate I ALWAYS have about 7 lbs of immediate tension loss when compared to the reference pull tension. The is according to RaquetTune which I think most users of this app will agree is pretty accurate.

I just thought of a test with racquet tune, it can also be a way that you can "calibrate" it to your string. Is there a way for you to try Racquet Tune while you still have tension on the string while on the stringing machine? In theory, you should get numbers that are nearly identical.

 

[a0f6459]

Purist,

The version of RT that I have allows you to pick string type as well as string diameter, so the criteria should be pretty specific.

I do pull each string about 10 seconds before clamping off after reading about what JayCee does.

After reading through some older posts it seems that you have been using the JayCee for a while.

Can you comment on the method that I posted in the 2nd post of this thread?

I'm asking because in the .pdf stringway JayCee document, he does not lower the tension on the middle mains. (the links he put int he Oracle thread at stringforum) However, on some other posts he advocates lowering the tension on the mains like the mehtod I posted in #2.

Which do you do?

 

[Purist]

a0f, I still don't think it would hurt to tension the string and see what Racket Tune says. If I still had an iPhone, I'd try it myself.

I haven't tried his method yet, mostly because in my humble opinion, the tensions on the strings equalize after hitting. I'm not sure how long it takes, but it seems to be that it wouldn't take too long. I know from pressing on the mains while stringing, it doesn't take much pressure to equalize strings next to each other. I realize that cross strings add friction that make it more difficult for the tension to equalize, but I still think it will after probably just a couple of hours.

I suppose one of these days I should give it a shot, though.

 

[spacediver]

I'm gonna try this on my klippermate tomorrow on my (18x20) kblade tour with Head Rip Control 17 @ a reference tension of 57 pounds. I'll report my results soon after

 

[Irvin]

My 2 cents

For the purpose of this example I will use a 16 x 19 racket and a 2 piece synthetic gut job. He states that the crosses in this case should be 4 lbs highers than the mains. (again he has reasoning for this but I won't go into that)

58 lbs reference tension

Mains

1) 6 center mains - pull at 58 lbs
2) Next 3 mains on each side of the 6 center mains - pull at 54 lbs
3) Final 2 mains on each side - pull at 62 lbs

* press the center of each string starting from the outside mains to the center mains, pressing both the right and left at the same time

Crosses

1) 1st 3 crosses - pull 62 lbs
2) Cross 4 through 17 - pull 58 lbs
3) 18 and 19 cross - pull 66 lbs


This supposedly should all come out to 56 - 58 lbs actual tension after the racket is immediately taken off the stringer.

Thoughts?

I would think the tighter you string the crosses the tighter the stringbed will be. If you string your mains at an average of 58 lbs and your crosses at a average of 62 you have effectively strung you racket at something higher than 58 pounds. How can you say your reference tension is 58 pounds when you use 5 different tensions to string your racket? This earlier thread shows when the crosses are tensioned the tension on the mains increase by about 91%. I am estimating here now but it looks like the tension on the mains rise in the first graph from 11 Kg to 21 Kg.

http://tt.tennis-warehouse.com/showthread.php?t=397033

If I wanted a tighter stringbed I would raise the tension and not just in a few select areas. Just set it and forget it.

I believe the points with the most stress on a racket are at the four corners where the mains and crosses come together around all those main skip holes. Using this method you have the maximum tension directly on those four points which could damage the racket.

Changing the tension 5 times while stringing a racket to reach some number is pure nonsense. Especially when that number is determined by an gadget that determines tension based on how the string vibrates. Many factors other than tension can make the vibration frequency change - string gauge, string composition, string length, string pattern, frame size, frame composition, frame dimensions, frame vibration dampening components, etc. These little gadgets serve you will if you understand them but I wouldn't bet on their accuracy in determining the tension of a string in a racket.

Irvin

 

[a0f6459]

Irvin,

Thanks for your input. I didn't come up with this method, only trying it after reading about it. For me it was just plug and play with the formula that he stated as far as how to tension based on the reference tension. I leave all the debates of the reason something works and why something doesn't work to other people. There seems to be no consensus anyways. I'm only interested in the result.

It seems that JayCee is pretty well respected so I gave his method a shot. If he says that with his method a stringer should be able to get within 2lbs of reference off the stringer, then I'm willing to try since I have my own stringer to experiment with.

Have you tried RaquetTune? It allows you to input many of the factors you have stated. From the feedback in this forum, I think a majority of people who use it find it very accurate. I also read through the posts by the creator of this app. He seems to have gone through great lengths and fine tuning to produce the best results with his program.

 

[a0f6459]

I'm gonna try this on my klippermate tomorrow on my (18x20) kblade tour with Head Rip Control 17 @ a reference tension of 57 pounds. I'll report my results soon after

Before you start, check out post #2

http://www.stringforum.net/board/showthread.php?t=3458

At the bottom he mentions a tweak for 18x20 string patterns.

Also don't forget to convert kgs to lbs. I know it's not exact, bit I just take 2 kg to mean 4 lbs.

 

[a0f6459]

Also, as I posted in my other thread, after a simple test on my Klippermate, I found it to be ~4 lbs light.

So to account for this I pull 4 lbs extra over the original reference tension.

So if I am looking for a reference tension of 58, I actually set 62 on the Klippermate. I hope that makes sense.


It also helps to write it all down first, much like I did in post #2 of this thread. It can be confusing at first.

 

[Irvin]

Irvin,

Thanks for your input. I didn't come up with this method, only trying it after reading about it. For me it was just plug and play with the formula that he stated as far as how to tension based on the reference tension. I leave all the debates of the reason something works and why something doesn't work to other people. There seems to be no consensus anyways. I'm only interested in the result.

It seems that JayCee is pretty well respected so I gave his method a shot. If he says that with his method a stringer should be able to get within 2lbs of reference off the stringer, then I'm willing to try since I have my own stringer to experiment with.

Have you tried RaquetTune? It allows you to input many of the factors you have stated. From the feedback in this forum, I think a majority of people who use it find it very accurate. I also read through the posts by the creator of this app. He seems to have gone through great lengths and fine tuning to produce the best results with his program.

I am not saying Jaycee'sn method isn't any good I just see too many reasons that lead me to believe it isn't. That's just my opinion and I could be all wet. I am well aware of Jaycee's reputation.

There are also proponent's of the proportional stringing method and those proponents are just as well respected even thought the proportional stringing method puts less tension on the shorter string and Jaycee does jus the opposite.

Then there is the Stringway Tension Advisor. They more often than not put less tension on the crosses because the strings are shorter. Many people on this forum swear by that method.

No I have not tried the RacketTune gadget/application. I think it is great that you can input lots of that stuff that I mentioned but with each different input there comes more error into the equation. When you get done with all the infernal (oops I ment internal) calculations you get a dynamic tension of the string bed. Then you have to convert that to tension - more error in the conversion calculation.

Given that same string and racket you could string it 10 times and if you are consistent you could obtain the same SBS within +/- 0.5 ponds very easily. If want a higher tension raise it if you want lower do the opposite. Why settle for +/- 2 pounds when you can improve that by 400% just stickin with what stringers have done for decades? This does not make any sense to me.

Sorry

Irvin

 

[Irvin]

Let me say this a little simpler. Let's assume I string 98 si racket at 60 pounds and end up with a RacketTune tension of 55 lbs. Somewhere somehow I lost 8% of my tension. But wouldn't it stand to reason if I strung a different but similar 98 si racket at 60 pounds I would end up with a RacketTune number of 55 lbs? If you want a tension of 50 it shouldn't be too difficult to figure out how to do that. Why go through all the changing of tension and figuring out when to raise and lower the tension with the manufacturer suggest 58 +/- 5 lbs?

Irvin

 

[spacediver]

Before you start, check out post #2

http://www.stringforum.net/board/showthread.php?t=3458

At the bottom he mentions a tweak for 18x20 string patterns.

Also don't forget to convert kgs to lbs. I know it's not exact, bit I just take 2 kg to mean 4 lbs.

yep, had already seen this, but thanks for the heads up. One thing I'm still unsure about at this point is how long to let the dropweight settle before clamping down.

 

[spacediver]

Given that same string and racket you could string it 10 times and if you are consistent you could obtain the same SBS within +/- 0.5 ponds very easily. If want a higher tension raise it if you want lower do the opposite. Why settle for +/- 2 pounds when you can improve that by 400% just stickin with what stringers have done for decades? This does not make any sense to me.

From what I've read on the Jay Cee method, it's not simply about achieving a close match between reference and actual tension. It's about better playability and longer duration of this playability.

 

[a0f6459]

Let me say this a little simpler. Let's assume I string 98 si racket at 60 pounds and end up with a RacketTune tension of 55 lbs. Somewhere somehow I lost 8% of my tension. But wouldn't it stand to reason if I strung a different but similar 98 si racket at 60 pounds I would end up with a RacketTune number of 55 lbs? If you want a tension of 50 it shouldn't be too difficult to figure out how to do that. Why go through all the changing of tension and figuring out when to raise and lower the tension with the manufacturer suggest 58 +/- 5 lbs?

Irvin

I totally understand what you are saying. It's what pretty much what everyone says.

If it takes pulling 66 lbs to get the 55 lbs that feels good then do that. If it takes pulling 60 lbs to get the 55 lbs that feels good then do that. That's the common advice I see and I have no problem with that.

I'm not here to defend the JayCee method, I only read about it last week. hahaha I think his point is that you don't have to overstretch your strings in order to get to the actual tension you want. Sure the tie offs are over stretched, but the majority of the strings are not. He also feels that by using his method you will reduce tension loss.

Whether this is true or not, I have no clue, I'm just testing it. This is the reason I started the thread, to find out if anyone has had success using this method, not to prove that this method works or is even correct.

 

[a0f6459]

Given that same string and racket you could string it 10 times and if you are consistent you could obtain the same SBS within +/- 0.5 ponds very easily. If want a higher tension raise it if you want lower do the opposite. Why settle for +/- 2 pounds when you can improve that by 400% just stickin with what stringers have done for decades? This does not make any sense to me.

Sorry

Irvin

Also, I am referring to getting only a 2 lb difference from reference tension to stringbed tension after immediately pulling it off the stringer. So if I pull 58, I should expect to have 56 lbs if I measure the stringbed immediately after completion.

This is different from saying I am settling for a 2 lb range in different tensions every time I string.

 

[a0f6459]

yep, had already seen this, but thanks for the heads up. One thing I'm still unsure about at this point is how long to let the dropweight settle before clamping down.

I think he recommends some arbitrary number like 8 seconds

 

[spacediver]

Just strung up two racquets using the Jay Cee method. The first one I messed up - I added and subtracted 2 pounds instead of 4 pounds. Second one I did correctly.

Interestingly, both racquets ended up with the same tension, although it remains to be seen which maintains it better and whether there are any differences in playability.

I used my klippermate with a reference tension of 57 pounds, and double pulled the first two crosses. I didn't pre-stretch my strings at all. I used Head Rip Control 17.

Using this online application: http://www.seventhstring.com/tuner/tuner.html I measured the string bed of my first racquet (which I did slightly incorrectly) and found the fundamental frequency to be 693 hz right after stringing. An hour and a half later, it dropped to 683 hz.

The second racquet, which has just been strung minutes ago, had a frequency of 693 hz.

For reference, the last time I strung at 57 pounds (using my regular method), the string bed was 679 hz.

My freqmess program tells me that 693 hz indicates 32.3 lb of tension.

I'm gonna try and measure my tension using a proper string meter next chance I get. I'm curious to see whether the freq mess program is yielding accurate results (it may be the parameters that I'm using are off somehow).

 

[spacediver]

45 min after stringing it, the frequency dropped to 685 hz (this is the racquet which was strung using the correct Jay Cee method).

 

[Ronny]

does that app racquettune actually work properly? i just strung a racquet at 58lbs (intended to anyway) and the tuner app said it was 48.....ive been stringing my racquets like this for past 3 years sigh

 

[GlenK]

It does work but you have to make sure the settings in RacTune for the racquet and string is exactly right. It sounds like something is off with a 10lb gap. I've never had anything that far off.

 

[max]

Irvin above points out some of the reasons for my skepticism.

Think about it:

You've got strings in a huge variety of materials, constructed in several different ways, different thicknesses. . .

The sound you give the iphone will vary considerable due to things such as temperature (affecting strings), how long your fingernail is, how far the phone is from the racquet, and so forth. . .

The iphone itself introduces variables.

Tension changes within a frame all the time, as the string elongates.

I just think it's a massively inaccurate way to measure string tension; I have little faith in it. I would think a fish scale more accurate!

 

[spacediver]

See this thread for why your actual tension might differ from your pull tension:

http://tt.tennis-warehouse.com/showthread.php?t=394230

 

[spacediver]

You've got strings in a huge variety of materials, constructed in several different ways, different thicknesses. . .

which is why you include that information in the calculations that racquet tune, and other apps, use.

The sound you give the iphone will vary considerable due to things such as temperature (affecting strings)

if the temperature affects tension, then this change will be reflected in the resulting sound.

, how long your fingernail is, how far the phone is from the racquet, and so forth. . .

All that is important is the fundamental frequency - this is a very stable property, and does not change with distance from phone or length of fingernail. You need to get a good solid pluck to get a good reading, but you'll know immediately if you don't get a good reading, because the results will be WAAAAAAAAY off.

You can gain insight into this by testing this online application here:

http://www.seventhstring.com/tuner/tuner.html

(and from what I understand, racquet tune uses two algorithms to filter the incoming audio signal so it may be even more reliable than the seventh string tuner).

The iphone itself introduces variables.

such as?

Tension changes within a frame all the time, as the string elongates.

right! and racquet tune will detect these changes.

I just think it's a massively inaccurate way to measure string tension; I have little faith in it. I would think a fish scale more accurate!

Read up on Cross & Bower's work - the relationship between string length (or area of a string bed), string density, and fundamental frequency is actually very robust.

Here's a good starting point:

http://www.physics.usyd.edu.au/~cross/CrossBower.pdf

 

[spacediver]

No I have not tried the RacketTune gadget/application. I think it is great that you can input lots of that stuff that I mentioned but with each different input there comes more error into the equation. When you get done with all the infernal (oops I ment internal) calculations you get a dynamic tension of the string bed. Then you have to convert that to tension - more error in the conversion calculation.

From what I understand, dynamic tension is the amount of force required to depress the string bed by a specified amount. It is not the same thing that racquet tune measures.