[pianotech] Worst Bass/Tenor Crossover in Universe

[Encore Pianos]

"Drive the board" is perhaps not the best choice of words on my part.
Strictly speaking, the only thing driving the board are the vibrating piano
strings.  The rest of it, as you describe below, are how best to establish a
set of conditions that will clearly isolate the speaking length of the
string, couple the string to the bridge, and do so in a manner that
conserves the energy provided by string with the greatest possible
efficiency; thereby resulting in long sustain and good volume.    

 

Elsewhere, Ron Nossaman describes the lattice construction of the panel and
ribbing on the Stuart, and I have seen pictures of same.  While I have not
heard a Stuart in person, I have heard recordings on  a decent stereo
system.  My feeling about the Stuart sound  has been what you describe below
is that it sounds like a board with no bearing - very linear and lifeless,
the sound just goes straight out, but has no arc or "push" to it.  It has
long sustain but, as we know, all sustains are not created equal in terms of
their contribution to musicality.  To my ear, it falls short of being an
improved system over the best "traditional" boards by a fair amount.

 

That said, could the Stuart or Phoenix agraffe be installed on a
conventionally constructed board with compression, crown, and bearing
skillfully blended together and sound very good in the ways we want a board
to perform?  I believe so.  

 

Will

 

 

 

 

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of David Love
Sent: Wednesday, January 09, 2013 12:12 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Worst Bass/Tenor Crossover in Universe

 

I don't believe that bearing and crown are required to drive the board. The
coupling of the strings to the bridge is enough to drive the board.  The
problem I have with zero bearing (if what you say about the Stuart pianos is
true) is that it seems to miss an important function of downbearing which is
to control impedance and to load some potential energy into the board by
flexing it downward.  The function of crown, then, is to create a domelike
shape that can be flexed downward much like loading a spring.  The unloaded
spring has less potential energy and lower impedance characteristics.  The
key to this (simply stated) is to create a system that is crowned adequately
and made light enough that the loading of the system with potential energy
via the setting of downbearing also pushes the impedance up to the targeted
level.  The pairing of those two processes is critical.  If the board is
designed with the idea of no downbearing, then it can't achieve the required
impedance characteristics by loading.  The board will have to be built
heavier.  Because there is no downbearing, the soundboard spring will be
devoid of loading with potential energy and the tone will be relatively
linear and lifeless.   

 

At least that's how I look at it.  

 

David Love

www.davidlovepianos.com

 

 

I have heard that agraffe bridge systems like the Stuart is designed to be
used at "zero bearing" ( I believe that Stuart claims to be such, if I am
not mistaken).  But I have never understood why, if all else about a
soundboard assembly is equal in design and construction, that this would be
the case.  It seems to me like they would have more or less the same
requirements of bearing and crown to drive the board. 

 

 

Will Truitt

 

 

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