S&S D Duplex

[A440A@aol.com]

Bill writes:

>What would really interest me is finding that when first 
>partials in the speaking length and the duplex length have a harmonic 
>relationship, that this accordance allows the standing waves on 
>either side of the bridge to stand longer. 

   I wonder if the duplexes have more effect via instantaneous impedance 
changes in the bridge than actually producing much sound on their own. Out of 
phase phenomena cause some profound effects on vibrating bodies.   
     One thing that seems to be missing from the discussion is the voicing.  
I have noticed the duplex scales creating more and more effect as the hammers 
in a given piano become harder and harder.  This is particularly evident in 
one studio that I tune.  A Hamburg B.   When we began using it, in 1998,  the 
hammers were on the verge of being too soft for the tracking use the piano 
was meant for.  I thought it sounded really great with all the duplex strings 
unmuted,(they had been taped off previously, but needing all the brilliance I 
could get, I opened them up).  
    As the years have gone by, the hammers have packed down, and the piano 
now zings pretty heavily.  We have resorted to taping the duplexes back 
up,(they really, really, have an aversion to me softening the hammers, even 
when I point out that it sure sounded good two years ago).  
    The contribution of the backstrings, and the front duplexes, seems to 
depend on the hammers.  A soft hammer, with the duplexes, gives a broad tonal 
range.  A soft hammer without the duplexes sounds dead.  A hard hammer with 
the duplexes zings and whistles,  A hard hammer without the duplexes sounds 
hard and empty, (which is what seems to please the producers most!) 
Regards, 
Ed Foote RPt