Duplex Scale Tuning

[Delwin D Fandrich]

----- Original Message -----
From: <ETomlinCF3@AOL.COM>
To: <pianotech@ptg.org>
Sent: Tuesday, December 21, 1999 3:44 PM
Subject: Re: Duplex Scale Tuning


> What a load.  Take a piano with a good duplex and play it with and without
> the duplex muted and the difference is very noticeable.  How can one say
that
> it is a marketing plan?  Lost energy ... we even see energy transferring
into
> the plate and almost all other components.
>
> Ed Tomlinson
>
-----------------------------------------------------------

That rather depends on what is used to mute the tuned duplex and how the
muting is done.  If something soft -- like a loose felt strip -- is used,
yes, there will be losses.  With the standard "tuned duplex" design there is
quite a lot of energy transferred to the string segment between the V-bar
and the counterbearing bar.  Some of this energy is ultimately fed back to
the normal speaking portion of the string, but the rest of it is dissipated
into the plate and is absorbed as heat.  When felt is used to mute out this
segment it acts just like a damper so there will be a loss of sustain.
Sometimes this loss is significant.

If, however, the muting is done with something rigid -- like a brass rod, or
bar -- then, no, there will be no discernable losses and the string
termination will be improved.  Even better, if the string deflection angle
can be increased and/or the length of the duplex segment made shorter -- it
is now no longer "tuned" and it is no longer vibrating significantly -- then
string termination will be improved and sustain will not be adversely
effected.  Indeed, it may well be improved.

Del