[pianotech] David Love--Centering the bridge--was S&S something er other

[David Love]

I'm thinking more about where over a membrane that the energy is input from.
Timpanists or drummers don't tend to strike their instrument exactly in the
middle but more off center.  They do that for tonal reasons.  Center loaded
ribs need to be larger to support the same load than non center loaded ribs.
The treble section of the Overs piano doesn't have the bridge centered in
that part of the piano.   Would it sound even better if you could center it?
The impedance characteristics of a diaphragm are different if you strike it
dead center than if you strike it off center?  Why would center be better?

 

David Love

www.davidlovepianos.com

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Dale Erwin
Sent: Wednesday, May 23, 2012 6:46 AM
To: pianotech at ptg.org
Subject: [pianotech] David Love--Centering the bridge--was S&S something er
other

 

Hi David
 Well perhaps there is no for sure answer. How about a thought? Loud
speakers are not the same as Soundboard panel shape but they don't build
them asymmetrically either. Yet the edges of the paper speaker cones are
thinner for more flexible response as should soundboard thickness be as
evidenced by the location of rib end cut outs and thinner panel over those
cut-outs due to diaphragmatic thinning, which is common. 
  If it is desirable to have a loud speaker pump energy/sound back and forth
when projecting sound, does it make sense that a sound board can do the same
more efficiently by having its primary energy distribution point, the
bridge, more located in the center of the rib & crown?
 I need to use the quality of the sound to answer the question.  I don't
always judge sound as better or best but view it like Baskin Robbins Ice
cream...37 different flavors , and we all like different ones at different
times. Right?. 
   I am for example blown away by a more symmetrical soundboard shape in Ron
Overs piano on the Rachmaninoff album entitled Lilacs. Trebles in a range of
timber like I've not hears before. I'll have some more please. &...then
there was my experience with my D in Eureka I posted about last weekend.
Loved the sound, a different flavor, but a stock shape, basically a tight
grain rib crowned Sitka board with white spruce ribbing.
 All that to say that... to center or not to center influences the sound and
if we like it then whistle a happy tune.
Beyond that we simply don't have enough information to predict what one will
do over another but there are differences that perhaps can be better
quantified by spectrum analysis. Or/and maybe hearing different board shapes
in a decent small halls under the fingers of pianists.

 Dale

Dale Erwin... RPT
Mason & Hamlin/Steinway/U.S pianos
www.Erwinspiano.com
209-577-8397

 
  

 

-----Original Message-----
From: David Love <davidlovepianos at comcast.net>
To: pianotech <pianotech at ptg.org>
Sent: Mon, May 21, 2012 12:39 pm
Subject: Re: [pianotech] S&S K(52) Restoration

There are several claims and apparent assumptions being made about the
benefits having the bridge located in the center of the soundboard.  What's
that based on?  Why would you necessarily want it centered?  It suppose it
sounds logical to have a centered bridge in terms of load bearing--maybe,
but what about the acoustical properties and impedance characteristics when
the bridge is centered versus when it's not.  I can think of as many
arguments for not centering the bridge as I can for centering it.  
 
David Love
www.davidlovepianos.com
 
 
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