more bridge design

[Farrell]

Del wrote:
> Drilling a
> few holes in the body of a bass bridge generally will not affect mass enough
> to make an audible change in the tone quality of the typical piano.

Yeah, but tell that to the Director of Marketing!

Terry Farrell
  
----- Original Message ----- 
From: "Barbara J. Fandrich" <pianobuilders@olynet.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Thursday, March 27, 2003 2:06 PM
Subject: Re: more bridge design


> >
> > ----- Original Message -----
> > From: "Don" <pianotuna@accesscomm.ca>
> > To: "Pianotech" <pianotech@ptg.org>
> > Sent: Wednesday, March 26, 2003 8:18 AM
> > Subject: Re: more bridge design
> >
> >
> > > Hi David,
> > >
> > > I would not call 30 pounds of downbearing a humungeous burden. The
> "holes"
> > > in a violin bridge are there to "filter" the sound. Downbearing on a
> fiddle
> > > is almost as much as that on a piano.
> > >
> 
> I'm assuming you are refering to the 'downbearing' on just the bass bridge.
> While it is true that the string bearing on many bass bridges is not much
> higher than this, the soundboard is affected by the string bearing on the
> tenor bridge as well. It is the complete, integrated system we have to
> consider.
> 
> Generally, holes are put in bass bridges to reduce their mass. That these
> holes are ineffective goes to the basic principles of soundboard impedance.
> This impedance is not linear across the frequency spectrum. In other words,
> it is frequency dependent. It is primarily mass-controlled at high
> frequencies and primarily spring-controlled at low frequencies. Drilling a
> few holes in the body of a bass bridge generally will not affect mass enough
> to make an audible change in the tone quality of the typical piano.
> 
> Del
> 
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