This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment 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 ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/cd/d0/2b/a6/attachment.htm ---------------------- multipart/alternative attachment--
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