[pianotech] YC Capo Bars

[Delwin D Fandrich]

I think the only way to determine whether or not a thesis like this holds up
in actual practice is to try it out--test it, and see what happens. Of
course it has to be a controlled test. In this case the only variable should
be the construction of the bridge itself. Outside of a factory this is close
to impossible but in the R&D department of a factory such as Baldwin once
had it is possible and I've done it. The test consisted of bridges with all
vertical laminations (Baldwin's standard construction), vertically laminated
bodies and solid maple caps (Steinway's standard construction) and all
horizontally laminated bridges (inspired by Kimball). These were all in
otherwise standard Baldwin Hamilton pianos. OK, not the best sounding piano
on the planet but they were readily available and reasonably consistent.
We--a variety of testing pianists--could discern no tonal differences at all
that could be either heard or measured (with what was then a
state-of-the-art HP FFT spectrum analyzer driven by an industry standard B&K
accelerometer). 

After trying for some time--without success--to find some discernable
performance variation among the various types of bridge the project was
ended.

Delwin D Fandrich
Piano Design & Fabrication
620 South Tower Avenue
Centralia, Washington 98531 USA
del at fandrichpiano.com
ddfandrich at gmail.com
Phone  360.736.7563


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Roger Gable
Sent: Monday, September 20, 2010 6:40 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] YC Capo Bars

Del,
I believe your correct to assume that cost is the driving factor for using
horizontally laminated bridges. In reading the various responses I believe
there is a consensus developing as to the pros and cons of laminated bridges
and bridge caps. The beginning of this thread started off on the wrong foot
when it was discovered that we were not all talking about the same thing --
bridge caps verses bridges. That being solved, this is what I believe can be
derived at this point from the thread.
Laminated caps are a plus to the stability of tuning and the development of
false beats. The selection of different materials will always be debatable,
but the concept is a plus for the piano industry. From the description of
construction, the cap, having thin laminates adhered to under great
pressure, essentially create a solid unit. The resin form a single unit
where the layers of the saturated wood impose little reflective character
within the laminate. But the horizontally laminated bridge is a different
"animal". Horizontally laminated bridges have be constructed, up to now, by
using a thicker wood laminate where the resin doesn't penetrate the various
layers of wood as much as the capping system This would create problems with
tonal development because of my submarine analyst, where energy waves would
be reflected at each laminate. It would be reasonable to assume that the
vertically orientated laminated bridge has the opposite effect, whereas the
energy has a clear uninterrupted path to the soundboard. What do you think? 
Anybody?
Roger Gable
P.S. I'm off to a chapter meeting