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>	This thread brings to mind a related question that I've 
>wondered about for some time. Steinway B's have varied in having 
>either double trichords or trichord and flat in the low tenor 
>section. Current ones have trichord and flat. In the 70's (the 
>vintage of ten I take care of at the university), they used double 
>trichords. Most  of the newer ones I have run across with 
>trichord/flat have one to several that have been changed over to 
>double trichords (I've done it myself on occasion).
>	I wonder what comments other folks might have on this. Was 
>there a good reason to go to trichord/flat? Were double trichords 
>the rule for a pretty long period? (A lot of the older vintage ones 
>I care for have double trichords, but that might have been 
>rebuilder's choice rather than following original design). Can 
>anyone always make trichord/flats work throughout? (Most of the time 
>I can get them to work, but I have fooled around far too long on 
>some and ended up swapping to double trichord in frustration).
>Regards,
>Fred Sturm
>University of New Mexico

Hi Fred and all,

In my experience the double trichords will cut off more quickly, but 
they are more prone to 'zipping' than the double/plain combination. 
However, the combination setup can be a pain unless the thickness of 
the plains is chosen such that they contact the wire just before the 
doubles.

So it comes down to a matter of relative damper timing, ie. the 
timing of the initial contact of the felt with the string (I'm 
referring here to the timing of the two felt pieces, the double and 
the plain, on a single damper). The spacing of the unisons will also 
cause variation in this timing, since the wider the unison spacer, 
the later will be the contact of the doubles with the wire.

Our practice in recent years has been to use all doubles in the lower 
tenor, changing to a combination with the plains out the back before 
changing to all plain felt as we move up the treble. I suspect that 
the cause of more 'zip' when the doubles are positioned 'out the 
back' is that the string excursions increase as we move further away 
from the agraffe. Plain felt is more immune to the 'zip' than are 
doubles. So if the plain felt contacts first, it takes some energy 
out of the string before the double comes in for the final 'chop'.

Ron O.
-- 

OVERS PIANOS - SYDNEY
      Grand Piano Manufacturers
      _______________________

Web http://overspianos.com.au
mailto:ron@overspianos.com.au
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