FW: Tuning Duplex

[Richard Moody]

----------
> From: Don <drose@dlcwest.com>
> To: pianotech@ptg.org
> Subject: Re: FW: Tuning Duplex
> Date: Sunday, June 14, 1998 7:25 PM
> 
> Hi all,
> 
> Clearly the duplex on a piano absorbs energy. Perhaps a better concept
for
> them is a filter to effect tone color changes in the manner a tone
control
> on a stereo may work if you only can *decrease* the amount of signal.
> Regards,
> Don Rose, 


An interesting concept, but one of many to consider. The most important
consideration of the string crossing the bridge is down bearing. This can
only be controlled behind the bridge, where the rear duplexes are, if
present.  The length of string behind the bridge is also a consideration,
in that a tail length of 1/8 inch it seems would have a different affect
on tone, than an 8 inch tail length. Perhaps there is an optimum distance,
but only a piano maker could know, as rebuilders have limited control over
this. That the tail length could also resonate and contribute to tonal
quality is idea behind the rear duplexes in my understanding. 
	Now along comes Baldwin with the "acu-just" hitch pins. A bold concept as
a string riding that high on a hitch pin might cause tuning instability. 
However it doesn't. Now if these segments are not muted, might they be
considered part of a "duplex" if so are the acu-just pins positioned in
such a manner to enhance the duplex effect?