Oops... Re: Unusual rib structure?

[Greg Newell]

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Del,
         Can this type of modal experiment be reproduced? and if so, how?

Greg Newell


At 06:25 PM 5/7/2003, you wrote:


>----- Original Message -----
>From: "Sarah Fox" <sarah@gendernet.org>
>To: "Pianotech" <pianotech@ptg.org>
>Sent: May 07, 2003 2:02 PM
>Subject: Re: Oops... Re: Unusual rib structure?
>
>
> > Hi Del et al.,
> >
> > So these rib ties were somewhat of a "missing link" between the old
> > no-cutoff-bar design and the more modern cutoff bar construction??? =
 Just
> > curious -- What was the evolutionary history, in a few sentences or=
 less?
> >
> > Thanks!
> >
> > Peace,
> > Sarah
>
>(Sarah, you should by now know better than to ask me to whip something like
>this off in "a few sentences or less....")
>
>Your Wissner, like almost every other U.S. built, and now Asian built,
>concert grand traces it design origins back to the Steinway Model D. The
>Model D, in turn, traces its origins back to a synthesis of various pianos
>that formed the transition between the harpsichord/fortepiano and the
>so-called "modern" piano. Steinway actually introduced very little that was
>truly new and original. One of the things he brought forward was the large,
>open soundboard. (Yes, I know that many pianoforte's did utilize some form
>of soundboard cutoff. Most of those I've seen, however, were basically
>floating cutoff's however. Much like the straps used by Steinway, et al.)
>
>By the 1880s piano makers were just beginning to investigate the
>performance of various rib structures and soundboard shapes and
>configurations. And by this time the Steinway pianos had already became
>exceptionally powerful marketing and manufacturing successes. Market forces
>then, as now, dictated that there were more followers than leaders in the
>madness that made up the late 1800s and early 1900s piano business. Even
>though many builders were building better, and better sounding, pianos than
>anything coming out of the Steinway factory, they tended to get lost in the
>marketing and promotional wars that could, and did, become quite brutal.
>
>Many piano makers seem to have had a reasonably good grasp of the basic
>design principles that go into making a good, efficient soundboard
>system--we still occasionally see their products in our shops yet today.
>Well though out and often highly innovative work. But they didn't survive
>the marketing wars any better then than they do today.
>
>Ironically, even though Steinway marketing today carries on about the large
>soundboard/large amplifier foolishness, at one time somebody in the company
>clearly understood the value of a good soundboard cutoff bar--witness the
>shape of the soundboards in some of their early vertical piano designs. But
>this never carried over to their grands. At least not in the later
>production designs that have now become locked in tradition--some of their
>earlier vertical piano designs did have relatively substantial cutoffs.
>
>Pianos with purely compression-crowned soundboards tend to lose their crown
>and, hence, their ability to carry sustain, through the upper tenor and
>lower treble sections relatively quickly. (Relative, that is, in terms of
>piano life.) Both the addition of the so-called "resonator" strap (which
>stiffens up the soundboard assembly in an area which really should be
>infinitely stiff) and the upper bellyrail-to-rim strap are indications that
>somewhere back there someone in their design department understood at least
>the basics of why this was happening. These two devices both help, but do
>not solve, the real problem.
>
>Back in the late 1980s I was working on a small soundboard design and was
>able to look at the design I had come up with using a rather primitive
>modal analysis model. It was fascinating to watch the bridge move up and
>down while a mode in the forward bass corner simultaneously moved exactly
>180=BA out of phase with it. Sound energy is simply transferred back and
>forth and is effectively cancelled. A second study done with a soundboard
>cutoff appropriately placed removed this area of the soundboard and
>increased the efficiency of the whole system.
>
>Del
>
>_______________________________________________
>pianotech list info: https://www.moypiano.com/resources/#archives

Greg Newell
Greg's piano Fort=E9
mailto:gnewell@ameritech.net=20

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