Duplex

[Delwin D Fandrich]

----- Original Message -----
From: <Duplexdan@AOL.COM>
To: <pianotech@ptg.org>
Sent: October 25, 2001 11:14 PM
Subject: Re: Duplex


> Dear Dave,
>
> Does the Baldwin have a Duplex Scale?

As currently designed and built, all grand pianos have what can be called a
duplex scale. The phrase comes from the Latin 'duplex,' literally "twofold,"
from plicare "to fold." The question is, is the length of the duplex
specifically and intentionally tuned to some partial of the fundamental
string length?



> Old Baldwins were made with triangular shaped oliquots, before the
acu-just
> system went into effect. All of these vintage pianos with adjustable
oliquots
> were designed to have a specific duplex scale tone that coordinated with
the
> tone of the speaking length. The moveablility of these oliquots was
> incorporated to allow for this tuning process.

Earlier Baldwin's had the back string rests pinned to a hole drilled in the
plate. They are not movable. The change was made as much for cost-cutting
reasons as to allow for 'tuning' them. There is no evidence that tuning the
back scale with these string rests improved the performance of the piano,
hence the subsequent change to the fixed vertical hitches.



> Tuning the duplex scale of any and all of these pianos can unquestionably
> improve the tone of the piano in particular regard to the quality of tone
and
> the sustain.

Oh, I think there is considerable question about this. My own actual
measurements revealed a slight increase in power at the affected frequencies
during the initial attack period and immediately following but this was
followed by a decrease in sustain as the energy coupled to the tuned
duplex--the aliquot part--was (presumably) absorbed into the plate.
Experientially, the tuned duplex system has also proven to be the cause of
much unwanted string noise.

It seems to boil down to a choice: with the tuned duplex system you might
get a slight increase in initial attack volume at certain harmonics. In
exchange you will have slightly shorter sustain and the increased
probability of string noises. Or, you can design the soundboard such that
sustain time is not--and does not quickly become--a serious problem and
forget about the tuned duplex system and its attendent string noise
problems. Personally, I prefer the latter approach.



> May I remind you that this is not my idea; it is, was and always will be
CF T
> Steinway's, who has the original patent, 126848.

What can I say? Lots and lots has been learned about the piano and its
design since old CFT sat in front of a drafting table. Smart as he was, he
wasn't perfect. Nor was the piano he created (in spite of the claim of
certain of his descendents). It was--or should have been--just one stepping
stone on the path, albeit a significant one. If our industry is to survive,
however, we must learn from both his experience and our own and then go on
from there.

Del