Yow-yow-yowing bass strings

[Joe And Penny Goss]

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Good thought David, and add to that the thicker wire will not go on as =
smoothly resisting the stringer resulting in little errors of diameter =
fluxuations causing false nodal points along the string length.

Joe Goss
imatunr@srvinet.com
www.mothergoosetools.com
  ----- Original Message -----=20
  From: David Love=20
  To: pianotech@ptg.org ; BobDavis88@aol.com=20
  Sent: Friday, January 24, 2003 2:08 AM
  Subject: Re: Yow-yow-yowing bass strings


  Since it occurs irregularly, it would make sense to look at the string =
manufacturing process.  My inclination (and I know you didn't want =
speculation) is that it has something to do with how the wrapped portion =
of the string is tensioned onto the core wire.  Too much tension, for =
example, might cause the core wire to twist, or somehow become torqued =
in a way that creates irregular or mismatched patterns when the string =
is set to vibrating.  Since this problem seems to occur mostly in the =
heavier wrapped strings, it may be because the thicker diameter of the =
wrappings in these strings requires more tension in the horizontal =
direction while the string is being wrapped.  The need for greater =
tension may tend to create more variation in tension, simply put, it =
might be harder to hold it steady.  It might be interesting to compare =
two strings, one that ! yows and one that doesn't, off the piano by =
allowing them to hang freely and see if the yowing one differs in terms =
of the amount of natural twist. =20

  Just a thought.

  David Love
  davidlovepianos@earthlink.net


    ----- Original Message -----=20
    From:=20
    To: pianotech@ptg.org
    Sent: 1/23/2003 6:58:17 PM=20
    Subject: Re: Yow-yow-yowing bass strings


    Thanks to those who have responded so far about this. I thought I'd =
better send an interim response, so you'd know I'm still listening.

    First, let me clarify what I know so far, and rule out a few things. =
I agree with Ron that this is definitely not a voicing issue, nor a =
termination issue. It's not in the leveling. It's not a leaky damper, =
nor an undamped segment of another string. It's not in the hammer at =
all, or rather in the angle of attack of the hammer (sorry Sarah, =
interesting post), since the strings exhibit at least similar behavior =
when plucked; at least the yowing ones still yow, and the clean ones are =
still clean. It seems to be in the string itself, and consists of beats. =
What I really want to know is what is beating against what, and while I =
really really really didn't want to speculate, the hypothesis that seems =
most convincing to me so far was post! ed by John Musselwhite:

    "Would those problematic single bass strings have LMFs [longitudinal =
mode frequencies] that are either unstable or out of tune with the rest =
of the string?"

    I have the CD from the Five Lectures, but I can't lay my hands on it =
right now. However, my memory is while the longitudinal modes produce =
different pitches, they are clear pitches, and not beating (?) Still, =
beating suggests non-harmonic stuff beating with harmonic stuff.=20
    -----
    Well, I took a look at Conklin's patent on longitudinal mode design, =
and now I understand more than I wanted to. It looks as if the =
longitudinal mode can be tuned by controlling the weight per unit length =
of the wire, including core and loading, and falls roughly in the area =
four octaves+  above the fundamental pitch of the string. I still don't =
know for sure if this can beat with the partials produced by the normal =
flexural modes, but I don't see why not, and if so, I don't understand =
how you cou! ld reliably make bass strings ever, especially if they are =
so sensitive that the same string on the same model can come out either =
wonderful or hideous.

    One of you scientists out there set us straight. I'm getting =
interested in this, and I don't have time to be interested.

    Bob Davis 
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