Comparing tensions with pitch

Discussion in 'Strings' started by ChrisBackAtIt, Feb 3, 2010.

  1. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41
    So I went to my pro shop and asked for both of my rackets to be strung at 58 with Luxillion ALU Rough.

    When I got home I was re-gripping and did the 'ol hit the frame of one racket on the string bed of the other, and vice-versa, and I couldn't help but notice a different pitch coming off each racket.

    I'm assuming this means either A) their is a flaw in the frame (which seems impossible given they are less than a month old), or B) the string tensions are different.

    Has anybody else had this problem, and am I diagnosing this situation correctly?
     
    #1
  2. LeeD

    LeeD Bionic Poster

    Joined:
    Dec 28, 2008
    Messages:
    37,247
    Location:
    East side of San Francisco Bay
    2 identical frames, grommets in the same condition, same strings, same tension. Higher "ping" means it's tighter somehow.
     
    #2
  3. julian

    julian Hall of Fame

    Joined:
    Dec 20, 2006
    Messages:
    3,331
    Location:
    Bedford,Massachusetts,US
    A bit dangerous

    Hi,
    1.you may ask a shop this question
    2.you may ask a shop whether both rackets were done by a same stringer

    Let me know
     
    #3
  4. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41
    Makes sense..
    To further geek out on it, being a music type, the difference is about a half-step down in pitch.

    My only other thought, is: Is their an issue with the Luxilon ALU Rough slipping during stringing?

    Thank you to all who are chiming in.
     
    #4
  5. LeeD

    LeeD Bionic Poster

    Joined:
    Dec 28, 2008
    Messages:
    37,247
    Location:
    East side of San Francisco Bay
    I'd take some time and check out WHERE the lower tension strings are. If it's perimeter, it's slipping on the machine for sure.
    And what tension, what rackets?
     
    #5
  6. Xenakis

    Xenakis Hall of Fame

    Joined:
    Sep 16, 2009
    Messages:
    2,431
    I'm new to stringing and know considerably more about music, when I have finished the mains I pluck the strings in pairs to see how even they are. Less than a semitone difference and I'm happy.

    I wonder if a conversion from pitch to lbs would be possible. For single strings and full beds. If so it would be a cheap way of determining tensions. Probably a lot of factors involved though like string lengths and gauges etc.
     
    #6
  7. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41

    Wow..now that's interesting.
    They are in fact slightly lower in pitch towards the outside of the bed. That's some ninja-knowledge right there.
    The higher-pitched racket has a way more consistent ring to it, and the lower pitch one tails off in pitch the further out from the center you go.

    For the record they are a pair of Head Liquidmetal Radical OS's strung at 58 with the ALU Rough.
     
    #7
  8. julian

    julian Hall of Fame

    Joined:
    Dec 20, 2006
    Messages:
    3,331
    Location:
    Bedford,Massachusetts,US
    Other stupid questions

    I hope that you are in US
    to simplify a conversation
     
    #8
  9. SplitStepper

    SplitStepper Rookie

    Joined:
    May 31, 2009
    Messages:
    308
    The one that is pitched lower was strung first. This is common. The higher pitched stick hasn't had a chance to lose tension yet.
     
    #9
  10. jim e

    jim e Hall of Fame

    Joined:
    Aug 4, 2007
    Messages:
    4,386
    Is it possible that one racquet was strung one day, as it can lose tension in the 1st 24 hours, then the other one was strung a day or two later, and would be a higher pitch as it did not have the time to lose its initial tension.
    If that may be the case, give it a couple days to even out and they then should be the same.
    Otherwise, possibly 2 different stringers would give 2 different results like mentioned earlier. Next time you give a shop 2 racquets be sure to specify that you want the same stringer to string both racquets so there would be some consistancy here.
     
    #10
  11. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41

    True.
    In this case they were strung within 30 minutes of each other..I do not know if it was two different stringers. That would certainly explain the difference.

    I'm going to get in the habit of checking them the second I get my hands on them rather than waiting until I get home. I think I would've requested a re-string if I was still at the shop!
     
    #11
  12. SplitStepper

    SplitStepper Rookie

    Joined:
    May 31, 2009
    Messages:
    308
    sorry...but i would have said no to a re-string if you were my customer. Its probably a difference of a pound because of timing. don't be such a brat. what, do you want your tennis club to buy two stringing machines so they can string your rackets at the same time?????
     
    #12
  13. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41
    Well, you drew me offsides.

    I'm not claiming to be tennis jesus, and the difference of an LB is going to throw my whole game off.
    I AM saying that if the job was to string 2 rackets at 58, they failed, and I noticed.
    Hopefully one day I'm skilled enough for it to make a difference, but in the meantime, don't whizz on my shoe and tell me it's raining.
     
    #13
  14. jhp49

    jhp49 Rookie

    Joined:
    Jan 14, 2006
    Messages:
    175
    Find someone with an ERT 300 and check the dynamic tension. You may want to purchase one if you are really picky about your string tensions and having identical racquets.
     
    #14
  15. BigT

    BigT Professional

    Joined:
    Nov 6, 2006
    Messages:
    1,220
    Are you sure your racquets are identical? W, SW, Bal?
    Good chance they are not.
     
    #15
  16. iplaybetter

    iplaybetter Hall of Fame

    Joined:
    Apr 3, 2007
    Messages:
    3,441
    Location:
    behind you, but i have to be somewhere else by the
    when i string a batch ill check the pitch of one against the one before and it should be a tocuh higher but after a few days they aughta be evened out...
     
    #16
  17. SW Stringer

    SW Stringer Semi-Pro

    Joined:
    Mar 10, 2004
    Messages:
    621
    Laying up the prepreg to make a racquet is still very much a manual process. If you could get two frames made by the same person and cooked side by side in the autoclave you would expect a closer match in the ping frequencies. But I doubt there's a way to track this without taking the grip off and looking at the manufacturing codes (if any) on the handle. I too had two identical Wilson frames that pinged a little bit off from each other when I first had them restrung, but after several restringings it was apparent that the same frame was always pinging higher than the other with the identical setup.
     
    #17
  18. Lambsscroll

    Lambsscroll Professional

    Joined:
    Oct 22, 2004
    Messages:
    1,471
    Location:
    United States
    .............................
     
    #18
  19. 2handsbothsides

    2handsbothsides Semi-Pro

    Joined:
    Jun 7, 2004
    Messages:
    441
    From your description it certainly sounds like you got inconsistent string jobs there. Its never a problem if you do your own, even with a basic $140 drop weight.
     
    #19
  20. travlerajm

    travlerajm Hall of Fame

    Joined:
    Mar 14, 2006
    Messages:
    4,443
    pitch (frequency) is proportional to the square root of string tension.

    A difference in pitch of one half-step is about 5% difference in frequency. This corresponds to a 10% difference in String tension.

    This means your stringer really screwed up.
     
    #20
  21. aksman

    aksman New User

    Joined:
    Oct 12, 2009
    Messages:
    78
    is there a difference in pitch for the same tension if the rackets have different head sizes?

    i.e. would a 100sq in head at 60lbs sound lower than a 95sq in head strung at 60?
     
    #21
  22. SplitStepper

    SplitStepper Rookie

    Joined:
    May 31, 2009
    Messages:
    308
    I'm just saying.....I've seen too many customers over the years complain about things that are not the fault of the stringer. As a teaching pro, I make alot more money than the stringers. When I see that the stringer has to work an extra hour for free just because some trouble maker wants to be a jerk, I feel sorry for the stringer. If I teach someone how to serve and they double fault once in their next match, I'm not giving a free lesson. It ticks me off when people are just so inconsiderate. You can ALWAYS find SOMETHING to complain about but WHY?????? Bottom line in this situation is that the string jobs were not done simultaneously. And why would they be????
     
    #22
  23. topanlego

    topanlego Semi-Pro

    Joined:
    Jan 9, 2009
    Messages:
    406
    Location:
    Vancity
    do they still ping different?
     
    #23
  24. mlewis721

    mlewis721 Rookie

    Joined:
    Feb 19, 2009
    Messages:
    220
    In the first place, I'm sure all of us have seen a player on tv tap one racquet against the stringbed of another, back and forth, trying to decide which racquet they'd rather use after being forced to go to their bag by a string breaking. In all likelihood, all the racquets in their bag were strung at the same tension with the same string. Do they look upset to find them not identical? Or even surprised? They aren't, because there's nothing unusual about it. What is unusual? Someone creating a big stink about it.

    Now, these players on tv usually get their racquets in batches. The average joe buys one here and there. I've had customers come in with a "pair" of Radicals. One made in Austria. One made in China. Or the Czech Republic. Are you sure you have a "pair"?

    I think most stringers would consider themselves to be on target if the DT readings on 2 successive stringings were within a point of each other. Does your stringer have a string bed deflection tester and provide you with the readings, on their label perhaps? The fact is even with identical DT readings, the "pitch test" will show variation.
     
    #24
  25. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41
    They do still ping differently.
    The change that HAS happened is that the one that had a lower pitch towards the outside of the hoop has"settled" for lack of a better word, and it's much closer to the same pitch as the center of the hoop.
    However...
    The two rackets are still entirely different in pitch.
    I've decided to not go back and ask for a re-string. What I will do, is request the same person to string my rackets if I'm getting two done at the same time.

    Now, in regards to this:
    While I understand your argument, I don't think that getting 2 rackets at different tensions is the equivalent of me double faulting if you taught me to serve. Your argument is fundamentally flawed.
    I find this error in stringing to be more like: If I go to SBucks, ask for two coffees, and get one that is decaf......or, I get a new set of tires, and one pair is inflated to one pressure, and the other is inflated to a different pressure...or better yet, I get a pair of shoes and they are different sizes.

    Lastly, I don't think the difference of timing between the two rackets being strung is the difference. The pitch is a half-step off, and as this thread has diagnosed, it appears that is from the stringing machine slipping during the process...in my opinion, if you are a commercial stringer, that's bad quality control.
     
    #25
  26. Steezmuffin

    Steezmuffin Rookie

    Joined:
    Mar 22, 2009
    Messages:
    249
    It could have to do with how close to the frame the stringer was able to clamp off the tie off strings. Depending on how the racquet was mounted (on six point mounts especially) The clamp may not be able to get as close every time.
     
    #26
  27. mlewis721

    mlewis721 Rookie

    Joined:
    Feb 19, 2009
    Messages:
    220

    IMO, you are not diagnosing this situation properly. So far, you are relying on your ear. If you do not have access to a string bed stiffness testing device and the stringer who performed the work does not have one either I would recommend you visit this site.

    The site is called freqmess. It is a program for calculating the tension of a racquet based on the frequency of vibration. You will need a microphone and a PC.

    Bear in mind that most players will not notice a discernable difference in play with less than a two lb increase/decrease in reference tension. I doubt you are looking at anything that large.
     
    Last edited: Feb 9, 2010
    #27
  28. kiteboard

    kiteboard Hall of Fame

    Joined:
    Jun 18, 2009
    Messages:
    3,919
    Location:
    Oakland
    IF the stringer does not ping out the ind. mains, like a guitar tuner, then one stick will always be higher, even if they are strung same time. Stick strung earlier will lose tension faster. Takes a real pro to identically ping out jobs so they match exactly. Not everyone has the touch or cares to do it. Even sticks strung with the same tech., same strings, same everything will ping out diff. if mains not pinged out to same pitch.
     
    #28
  29. SplitStepper

    SplitStepper Rookie

    Joined:
    May 31, 2009
    Messages:
    308
    Good choice to not take the racket back. You have avoided making yourself look like a trouble maker. It reminds me of someone complaining at a restaurant about their food. How embarrassing. Don't bite the hand that feeds you. If it makes you feel better hire P1 to fly in and do your stringing.
     
    #29
  30. fuzz nation

    fuzz nation Legend

    Joined:
    Oct 20, 2006
    Messages:
    8,657
    Yep, the bigger head with the longer individual string lengths would have a lower ping. The longer the string, the more tension your need to get it to vibrate at the same frequency as a shorter one when you hit it or pluck it.

    Chris, I didn't see whether or not you played with the two racquets to check on any difference in feel or performance. I'm pretty sure that you won't get much if any difference out of them from the sounds of those... ahem... sounds. Sorry, couldn't resist.
     
    #30
  31. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41


    I did hit with them, and I'd love to say that I could tell a definite difference, but I couldn't.
    The A.D.D. in me just wants some symmetry when it comes to a pair of rackets.
    What's the point in matching up specs to get a close pair if you can't get them strung the same? Seems like that is as important as swingweight, balance, etc.
    At least now when my forehand sales long I can blame it on the string job....maybe..yeah.. I'll go with that!
     
    #31
  32. jazzyfunkybluesy

    jazzyfunkybluesy Banned

    Joined:
    Oct 20, 2009
    Messages:
    1,707
    Big difference in pitch would mean an overall difference in tension. There are so many ways to screw up a string job even if you have excellent equipment. I bought a machine and highly recommend anyone who plays alot to do the same.
     
    #32
  33. Irvin

    Irvin G.O.A.T.

    Joined:
    Mar 15, 2007
    Messages:
    12,271
    Location:
    Marietta, Ga
    Good chance there were not strung on the same stringing machine. I normally find, especially with poly strings, that the frequency is the same given same string, tension, and racket after a few hours.

    Irvin
     
    #33
  34. SplitStepper

    SplitStepper Rookie

    Joined:
    May 31, 2009
    Messages:
    308
    I understand wanting to have two sticks with the same tension. I carry 3 with me but like to have them at different tensions. Even playing indoors, the temperature can vary. The colder it is, the looser I want my strings. Especially playing outdoors, I really like to have a few different tensions.
     
    #34
  35. jim e

    jim e Hall of Fame

    Joined:
    Aug 4, 2007
    Messages:
    4,386
    After playing for so long, you reailze that its always the equipments fault don't you know.
     
    #35
  36. 000KFACTOR90000

    000KFACTOR90000 Professional

    Joined:
    Dec 6, 2007
    Messages:
    857
    One thing to try to remember is when you hit the racquets against the string make sure you are holding both racquets in the same place on the frame.

    If you are holding one further up the frame the pitch will be different.
     
    #36
  37. mlewis721

    mlewis721 Rookie

    Joined:
    Feb 19, 2009
    Messages:
    220
    Eh? Exactly how does one stringer string 2 racquets at the same time? The only way I can imagine this is on 2 separate machines. And I think most would agree that there would be more variation using 2 different machines than there would be from stringing them 1/2 hr apart on one machine.

    As to this pinging voodoo you are proposing....I am thinking most stringers (even tour level stringers...no, make that especially tour level stringers) are trusting that the machines they have invested thousands of dollars in are capable of controlling the tensioning of the individual mains, otherwise we would all be standing around with oscilloscopes and calculators plucking away at main strings all day long trying to compensate for differences in string length and hoo boy, I'm getting a headache.....
     
    Last edited: Feb 7, 2010
    #37
  38. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41
    Well this leads me to a point I'm interested in.

    Are all string machines calibrated to the same standard?..and..
    Is stringing a racket so specialized that two different people on equivalent machines will end up with a totally different finished product?
     
    #38
  39. SplitStepper

    SplitStepper Rookie

    Joined:
    May 31, 2009
    Messages:
    308
    two different stringers can end up with slightly different results. not completely different results. most stringers are trained to single pull, clamp as close to the frame as possible, stay one weave ahead, don't leave the racquet half done for awhile, etc.etc.
     
    #39
  40. SplitStepper

    SplitStepper Rookie

    Joined:
    May 31, 2009
    Messages:
    308
    also, it depends on which calibrator you are using. they can also slightly differ. i would recommend sticking to one machine, hopefully same technician but not as important as the machine because they should be trained the same way.
     
    #40
  41. SW Stringer

    SW Stringer Semi-Pro

    Joined:
    Mar 10, 2004
    Messages:
    621
    ChrisBackAtIt said: " . . . I did hit with them, and I'd love to say that I could tell a definite difference, but I couldn't. . . . " and then says: " . . . Seems like that is as important as swingweight, balance, etc. . . . " but of course he COULDN'T tell a difference!

    So here's the problem: You can HEAR a difference between the two racquets but you can't FEEL a difference. I don't think it's A.D.D. but O.C.D. that has you hung up. The authors of the "Physics and Technology of Tennis" tell the results of a test done on the satellite tour with two racquets strung with a ten pound difference in the reference tension. Players were asked to hit with the two racquets (but specifically told NOT to ping the stringbeds) and tell which racquet was strung tighter. Ninety percent of the tour players couldn't tell the difference!

    You say one racquet pings half a step higher than the other. So for example if one pinged at C5 (523.25 HZ) then the other one would be at 538.8 HZ. The tensions are proportional to the square of the frequencies so if the high pinging racquet was strung at 60 lbs then the apparent tension of the low pinging racquet would be 56.59 lbs, or 3.41 pounds lower than the other stick. What your "test" has already confirmed is that you can't "feel" the difference between two sticks strung with reference tensions 3.41 pounds apart. No big deal, since most tour players can't tell the difference between racquets strung 10 pounds apart.

    I'd suggest getting your free copy of freqmess and measuring the exact frequencies of your sticks just to check the accuracy of your ears. Beyond that try to control you OCD! :razz:
     
    #41
  42. trigger1

    trigger1 New User

    Joined:
    Apr 9, 2004
    Messages:
    39
    Location:
    San Jose CA
    just to further beat a dead horse

    So I completed my first string job and noticed that the ping I have is different from my "professionally" strung racquet. Both the same stick same tension BUT different string types.

    1) Professional job- Prince Multifilament 16G.
    2) Rookie job- Eagnas Nylon 16G.

    Will the string type make a difference. I would not think that much if any.

    I did calibrate the machine in advance.

    I apologize in advance if this was answered but I could not find it.
     
    #42
  43. jim e

    jim e Hall of Fame

    Joined:
    Aug 4, 2007
    Messages:
    4,386
    Different string type can make a big difference. Not only is the string make up different but the gauges between the two strings can be off as well, as they have a range to be in for the gauge thickness, and that does vary from one string type , or manuf. to another.

    BTW, the gauge is the diameter of the string usually under tension, not the gauge in the package for those who chose to measure the gauge., so with higher tensions, some strings could fall into a different gauge level.An example of this could be like a string that measures 1.26 mm unstrung would appear to be either a 16 or 16L. but after tensioned in a strung racquet, the diameter might become 1.21, which would make it a 17-gauge string.

    Example of ranges that gauges have:
    U.S. Int'l. Diameter
    16 8.5 1.26-1.34 mm
    16L 8 1.22-1.30 mm
    17 7.5 1.16-1.24 mm

    Therefore a string with a gauge of 1.24mm could fit a 17g. with one manuf. and 16L with another, or a string can be a 16g. and be 1.26mm, and another can be 16g. and be 1.34mm.
    I would not be surprised if manufacturing tolerances with some string companies were off as well, even though there is a good amount of latitude here.
     
    Last edited: Feb 8, 2010
    #43
  44. mlewis721

    mlewis721 Rookie

    Joined:
    Feb 19, 2009
    Messages:
    220
    I wish you had phrased this better because there is no short answer for the question the way you are posing it. I began a long answer and aborted it. Here's a start. All stringing machines are NOT created equal. If you keep all other variables the same, switching from one machine to another can make a huge difference.

    Yessiree bob. In fact, two different technicians stringing on the very same machine at the same shop can produce vastly different results.

    But, setting this all aside for a moment.

    A customer brought me 3 "identical" racquets yesterday for stringing. All the same string, same tension. I tested each with a Beers ERT-700 after stringing. DT on all three was 38. Retested this afternoon. Two are down to 37. One to 36. They all sound different when tapped. According to freqmess:
    1. 697.286 hz
    2. 696.143 hz
    3. 682.857 hz

    The difference between 1 and 2 is so small as to be negligible yet when tapped there is a definite difference. The third one is a surprise to me. I cannot offer an explanation except to say none of the serial numbers on these racquets is anywhere close to being sequential. As this is the first time I am seeing frame #3 I can't speak to whether it is just softer than the others. I am guessing it is. Will know more the next time it is brought in. But that is why I record data like this in the first place.

    Now, if this customer's name was Chris and he came back to me the next day all hopping mad because he is thinking it is my fault that his racquets don't "ping" the same I would not be pleased. All three racquets were strung on the same machine, by the same stringer one right after the other and produced the same DT reading on the same meter immediately after stringing. As far as I'm concerned, job well done.
     
    #44
  45. mlewis721

    mlewis721 Rookie

    Joined:
    Feb 19, 2009
    Messages:
    220
    Where are you getting this from? Are you suggesting that an industry that has no real standards has established one for the conditions under which those non-existent standards are applied?
     
    Last edited: Feb 8, 2010
    #45
  46. jim e

    jim e Hall of Fame

    Joined:
    Aug 4, 2007
    Messages:
    4,386
    First off, I would not post this if it came from a bogus source.
    This is from the USRSA web site.I am not suggesting anything, just passing on information that I came across a while back.I found it rather surprising that it is the gauge of the string under tension, with no set tension as a reference.
    This is what is there, and I quote:" The string gauge is usually measured with the string under tension."
    The example that I gave was also following that comment, also quoted, "a string that measures 1.26 mm unstrung would appear to be either a 16 or 16L. When strung, however, the diameter might become 1.21, which would make it a 17-gauge string."

    Go to the USRSA web site, (you need to be a member to access the following part), Then click on the top tab that says reference, and then click on string gauges, and its listed right there, not my words but theirs.
    If you are not a member of the USRSA, just ask someone you know that is, to go to this spot on the site, and it can be verified where this came from.
     
    Last edited: Feb 8, 2010
    #46
  47. mlewis721

    mlewis721 Rookie

    Joined:
    Feb 19, 2009
    Messages:
    220
    Jim,

    Well, I had a feeling because it sounds like Greg Raven. And if he wants to expand on it some that would be great. He had an opportunity in an earlier thread over at GSS and chose not to.

    I happen to have a number of 1/2 sets of string here and a digital micrometer so I compiled a small list of 13 strings just for kicks. Mind you, in addition to US gauge, the vast majority of mfrs include the diameter in mm's on the package. I used that. I excluded a number of poly's that I did not feel comfortable measuring because they are not round.

    As you can see, the mfrs stated dia and the actual dia tends to be pretty close, with roughly half at or below and the other half slightly above. It never occurred to me to attribute this to anything but loose tolerances.

    [​IMG]
     
    #47
  48. mlewis721

    mlewis721 Rookie

    Joined:
    Feb 19, 2009
    Messages:
    220
    The string type will make a difference but gauge will make a bigger difference. I would be really surprised if Eagnas Nylon wasn't actually a 15L. Additionally, if you played with racquet #1 and didn't play with racquet #2 or there was a large time lapse between the two stringings it isn't realistic to expect them to ping the same.
     
    #48
  49. ChrisBackAtIt

    ChrisBackAtIt New User

    Joined:
    Dec 19, 2009
    Messages:
    41

    Good thing I turned to the forum before I ran back and caused trouble!
    Sounds like I had a knuckle-sandwhich coming. :shock:
     
    #49
  50. Steezmuffin

    Steezmuffin Rookie

    Joined:
    Mar 22, 2009
    Messages:
    249
    Just throwing this out there. There is a lot of talk about the same racquet being different due to where it is made, ect. No one (that I have saw) has mentioned the differences in the same kind of string manufactured at different times and perhaps handeled differently.
     
    #50

Share This Page