Weinreich unisons(wasTuneoff)

[A440A@AOL.COM]

Terry writes: 
<<I use the (what I think to be) more common approach of tuning the

center string to the SAT III and then tuning the two outside strings. Can

you give the philosophy behind your approach   and how do you mute.

P.S.  What it a Weinreich?

 
Greetings, 
   Gabriel Weinreich (I hope I am spelling it right), published  "The Coupled 
Motion Of Piano Strings" in the late 70's.  The gist of his research was that 
the coupled motion required, at times, that the strings not be tuned to the 
exact same pitch in order to produce the longest sustain and clearest 
sounding tone.  
   In a short summation,  the coupling of the various strings causes them to 
interact via the bridge.  With two strings, it is rather simple, but with 
three, there can be several overlapping phase relationships.  It can become 
as complex as the salt-spray on the ripples on a wave on a swell on the 
ocean!  If all strings are perfectly matched, the energy from the hammer is 
"dumped" into the bridge, all at once.  The bridge moves a lot when this 
happens, causing the energy to used(transmitted) all at once.  The resulting 
note may be louder at impact, but suffer a loss of sustain and bloom.   
   If the strings' vibrations are hitting the bridge in an opposing pattern, 
they tend to stiffen the bridge against the oncoming pulse from the other 
string.  This stiffening is responsible for more of the energy being 
reflected back into the string, causing the sound to sustain longer.   A 
careful ear can hear the tonal difference in a unison that results from very 
small changes.  
   I tune the outer two strings to the machine for several reasons.  One is 
that I only move the mute once per note.  Here is my pattern; 
mute begins between the left and middle string, tune right string, move mute 
to other pair and tune left hand string, pull mute up partway to damp only 
middle string and listen to your "machine unison" of the two outer strings.  
It should be dead-nut still.  If so,  put mute out of way (in the next 
trichord), close eyes, pull middle string sharp and let it down until your 
ear tells you you have acheived the nicest sound from that note.  It will 
usually just make the machine move, rarely do all three stop the lights 
equally.  
    This is the fastest and most consistant way I have found to make all my 
unisons sound the same.  It may not work for everybody, but I can suggest the 
machiners give it a try.  It allows the ear to make that final .2 cent 
allowance that brings the three strings into a most pleasing phase 
relationship,  and it does it quick and dependably. 
Hope this helps, 
Ed