---------------------- multipart/alternative attachment At 09:21 PM 2/21/2004 -0600, Ron Nossman wrote: >>> From recent discussions, I don't know if negative front bearing is=20 >>> viewed as an issue of much concern any longer, but, in any case, I=20 >>> think all this might help the consistency of the information people=20 >>> supply with this tool. >>> >>>David Skolnik > >Of course it's an issue of concern. Why wouldn't it be? Hi Ron N Sitting in my draft file since 2/2/04 is my attempt to effectively respond= =20 to your last post in the thread "No downbearing: REVISITED". I know you=20 felt I was not being clear in what I was trying to say at that time, and,=20 while I felt quite frustrated by the communication break down, I also felt= =20 as though the interchange had lost the interest of the list, in general.=20 The inevitable consequence of this lack of resolution of what are probably= =20 semantic misunderstandings is that the same disagreements continue to=20 reappear. Let me try again to ask my questions clearly and/ or make sure I= =20 am understanding your position correctly. WARNING!! Any perception of 'tone' or attitude is a function of either the= =20 reader's projection or the writer's fatigue. >>downbearing is to compress the board to raise it's impedance to meet the= =20 >>requirements of the string scale. It isn't to enhance the coupling=20 >>between the string and the bridge surface. The bridge pins do that quite= =20 >>nicely. How would you define "coupling", in this case? Does the front edge of the= =20 bridge play any role in defining the string termination? If so, how is=20 that function affected by 1) no contact (string climbing pin- see next=20 quote 2) glancing contact with no force 3) some downward pressure? If it= =20 does not, does it have any function other than supporting the bridge pin? >I don't see any possibility of a string riding up a bridge pin unless the= =20 >pin is near vertical, and the bearing is negative. Bridge pins set at a=20 >20=B0 slant, with a 10=B0 offset angle will hold a string to a bridge top= even=20 >with some negative bearing. Are you saying that a string riding up a bridge pin would require BOTH=20 negative downbearing AND near-straight bridge pins? It's true that,=20 without the bridge pins, there could be NO negative downbearing, and that=20 until the string DOES move up, negative front bearing simply represents a=20 potential instability, though, as a component of negative net downbearing,= =20 it also represents an absence of impedance-enhancing loading, albeit on one= =20 string. In any case, it's hard for me to believe that you have not=20 encountered innumerable examples of strings which visibly settle downward=20 when tapped (gently). >The side bearing from this offset, and the slant of the bridge pin, clamps= =20 >the string to the bridge top. It's the "clamping" concept I'm having trouble with. If there is positive= =20 downbearing, the need for further clamping would seem somewhat=20 redundant. If there is negative downbearing, and thus, no bridge loading,= =20 what is the purpose of clamping the string to the bridge surface? Wouldn't= =20 the vibrational energy be conducted to the bridge by the pins, even without= =20 the bridge surface contact? My problem with the concept and terminology of "clamping" is that it=20 encourages an image of the string exerting a vertical pulling and pushing=20 force upon the bridge, which I believe is inaccurate. DS asked: >>>>Are there any builders or rebuilders out there who would, with no=20 >>>>hesitation, put out a product which had zero or negative downbearing? >>Ron N replied: >>>With an existing soundboard, no. Ron N also said: > if the soundboard wasn't designed for zero to negative bearing, I surely= =20 > wouldn't accept anyone's assurances that zero to negative bearing=20 > measured in the piano wasn't a problem. Good. So, what are your concerns with negative downbearing? David Skolnik RPT, DBH ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/ed/91/ea/9a/attachment.htm ---------------------- multipart/alternative attachment--
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