S&S D Duplex

[Delwin D Fandrich]

----- Original Message -----
From: "Sarah Fox" <sarah@gendernet.org>
To: <fordpiano@earthlink.net>; "Pianotech" <pianotech@ptg.org>
Sent: November 17, 2002 2:01 PM
Subject: Re: S&S D Duplex


.
>
> In the end, could it be that the biggest benefit of a tuned duplex scale
is
> the "freeing up" of the vibrations of the strings and bridge by
eliminating
> the need to mute the strings on the far side of the bridge?  After all,
> mutes of any kind work through frictional dissipation of vibrational
energy.
> Isn't it reasonable to expect that muting adversely affects a note's
> sustain?  If the purpose of muting is to kill objectionable ringing in
> nonspeaking string segments at inappropriate frequencies, isn't an
alternate
> solution to tune those frequencies to where they are appropriate and
> therefore not objectionable?

Alas, I am not one of Duplex Dan's experts. Over the years I have found
tuned duplex string segments--whether they are in front or in back of the
intentionally speaking string segment--to be more trouble than they are
worth. While 'tuned' string segments toward the back of the bridge are less
troublesome than those in front I have still not found them to be of any
substantive value. And, if they are 'tuned' to one of the higher harmonics
of the fundamental and the backscale becomes shorter than optimum, they are
a downright detriment to piano tone production. Now, in fairness to Duplex
Dan, I have not yet attended one of his class demonstrations though I have
seen classes presented by others--presumably qualified--and I have done
considerable work with the things myself. Enough to convince myself that the
real gains are to be found in optimizing the efficiency of the soundboard,
matching it to the stringing scale, supporting it well and keeping the
backscale long enough that it does not unduly restrict the motion of the
bridge/soundboard assembly.

I am not at all impressed with any list of current (or, for that, past)
manufacturers who use the system. Or claim to. Please understand that while
many claim this dubious 'feature,' as a marketing aid, in reality few
actually bother tuning anything either in front or in back of the strings'
speaking length. Not even Steinway. And for good reason: they have learned
that marketing claims sell more pianos than does substance. Why do people
buy Bayer aspirin instead of the chemically identical generic? It is enough
that the appearance is there in the form of some kind of segmented bearing
bar or, possibly, even individual string rests even if nothing is really
tuned. Most manufacturers who have really worked with this for a few decades
have learned that it really doesn't matter if these string segments are
tuned to any specific harmonic or not. So, given today's copy-cat approach
to piano design it should not surprise us that manufactures would flock to
copy an inexpensive design 'feature' that has been heavily promoted for over
a century even if there is little or no substance to the various claims made
for it.

Nor am I frightened by claims that Baldwin's demise can be laid to the fact
that some years ago they abandoned the tuned duplex backscale arrangement.
Unless some correlation can be made between that and the past several
decades of unbelievably bad management. An equally valid claim could be made
that only the performance gains made by dropping the tuned duplex backscale
system and switching to the vertical hitchpin arrangement kept the company
going as long as it did. Take your pick.

The major problem I have with this whole tuned backscale discussion is that
it requires thinking of each string (or unison) and its associated bridge
segment as a series of mono-chords (mono-unisons?) acting independently of
each other. The do not, of course, what happens to one unison happens also
to the adjacent unisons for some distance up and down the bridge. In other
words, when the strings of, say, C-64 are vibrating and causing the bridge
to move it is not just the backscale strings of C-64 that are set in motion
in response. The backscale strings of all of the unisons for some distance
on either side of C-64 are also set in motion. In real life it would be
pretty difficult to come up with any backscale length
arrangement--deliberately tuned or not--that did not have at least a few
adjacent backscale string segments harmonic with some driving string
segment. (Unless, of course, you try to explain the generation of sound
energy by the soundboard in some way that does not have the bridge moving in
response to the vibrating energy in the strings. Then, I suppose, all bets
are off.)

Del
Delwin D Fandrich
Piano Designer & Builder
Hoquiam, Washington  USA
E.mail:  pianobuilders@olynet.com
Web Site:  www.pianobuilders.com