My piano, Chickering

[Delwin D Fandrich]

Ron Nossaman wrote:
> 
> It's a matter of the length of string in contact with the agraffe or V bar
> that kills the bleed through into the front duplex, correct? 

Not really, no. It's more a matter of string deflection angle and duplex
length. --ddf


> When the radius
> of the contour of the termination is smaller than the string would naturally
> assume at a given entry/exit angle, you increase the angle, diminish the
> se-saw effect at the bearing point and minimize the bleed through. OK,
> wouldn't the same result come from increasing the radius of the bearing
> surface to increase contact area with the string? We're pretty well locked
> in to (sort of) standard agraffe configurations, but most of these problems
> occur in the V bar'd sections anyway. I wouldn't see this as a viable
> rebuild option, where increasing the angle *is*, but designers and
> manufacturers have had a lot of years and a lot of chances to play with it.
> Why are we still braiding front duplexes in new pianos to squelch that front
> duplex Banshee?

Again, please forgive me if I defer to what I have already written in
the Journal. This is a far more complicated issue than I care to (or
have time to) go into here. --ddf


> >> Would you use the same argument for greater side bearing at the
> >> terminating bridge pin?  Why not?
> >
> >Yes. There are several other factors involved here, though. The bridge
> >pin is typically angled with reference to the bridge surface. This helps
> >to clamp the string against the top surface of the bridge. There is a
> >second bridge pin located 15 to 25 mm behind the first that also helps.
> >In the case of the V-bar its best to stop all of the wave energy and
> >keep it in the string. At the bridge, the idea is to actually get some
> >amount of energy to couple through the bridge and move the soundboard
> >assembly.
> 
> Gotta comment here. Greater stagger angle across the bridge means the string
> is more reluctant to render through and makes a stable tuning that much less
> likely. It also increases the likelihood that the bridge will crack from
> excessive side bearing pressures. There is plenty of contact surface across
> the top of the bridge to absorb anything that bleeds past the front bridge
> pin.

By greater, I meant approximately 10 to 12 degrees which is fairly
typical, I think. I should have been more specific. These angles will
not cause any problems with either tuning or bridge cracking. --ddf


> >> Originally the Chickering had felt glued to the plate just in front of the
> >> hitch pins.  Would you have left the felt there?  If so why?
> >
> >Actually, I'd have replaced the soundboard and capped the bridges. There
> >is no way that a soundboard that old can have the necessary amount of
> >stiffness that it needs to provide the proper impedance load to the
> >strings. Both sustain and tone quality will have suffered. Assuming that
> >wasn't an option for you, I'd suggest that you still need a certain
> >minimum amount of string load on the soundboard. Forget about crown,
> >there isn't going to be much left after a hundred years, if any. But
> >without some sting load against the bridge (i.e., downbearing) you're
> >going to have a tough time realizing even what little tone performance
> >the old board does have left to give.
> >--ddf
> >
> 
> I agree with Del that the board should have been replaced. I disagree that
> you need more bearing. If you don't have crown, adding bearing isn't going
> to make it well.
> Ron Nossaman

I don't think I implied that adding bearing was going to "make it well."
At least I certainly didn't intend to. Adding bearing will not improve
the condition of the soundboard in any way. But with a reasonable amount
of string load on the soundboard, the piano will probably sound less
bad. Taking away bearing will not improve the condition of the
soundboard either. Nor will it extend its life—that has already ended.
Decreasing bearing will adversely affect what little acoustic capability
there is in the soundboard and will not help restore the soundboard or
extend its life in any way. So why do it?
--ddf