My piano, Chickering

[Delwin D Fandrich]

Michael J. Wathen wrote:
> 
> 
> ...Once again you can visit the site below to see a picture of a modified
> string rest system. The picture is the Chickering in question.  Originally
> it had pieces of felt glued to the plate adjacent to the hitch pins.  I
> wanted first of all to control the down bearing across the bridge to make it
> as minimal as possible because the board was over a hundred years old.  The
> rest are made from sections of cut up bass strings.  I had a set of unused
> bass strings sitting around.  I could pick from a full range of diameters to
> raise the string till I achieved the right bearing.  I should note here that
> all this was required because I replaced a hopeless bridge cap.

The resolution wasn’t quite good enough for me to get a clear picture of
what you’ve done. It appears, on my screen at least, that you’ve simply
used the bass string (mentioned below) as a string rest in front of the
hitch pins. Correct?


> The second
> reason for changing the system was that I wanted to get a little resonant
> sympathetic vibration from the soundboard. 

Why? And what do you mean?


> This piano has agraffes all the
> way to the top. So I also went to a machinist and had him make some 3/8"
> half rounds out of high carbon steel to act as string rests (counter bearing
> bars) between the tuning pin and the agraffe. 

Good. We regularly replace the so-called “tuned aliquot duplex bars”
with a simple, but much more efficient bearing bar system. I typically
use brass half-round or half-oval in strips which can more easily be
bent to follow the agraffe (or V-bar) line. This bar is located such
that it creates a string deflection angle across the V-bar that is
adequate to fully terminate the speaking length of the string. Without
fail, this change improves both power and sustain through both treble
sections.


> These sections also have some
> sympathetic resonance but more importantly I think that they return some
> energy to the speaking portion of the string.  

Precious little, actually. See my articles on duplex systems...


> Now I not sure what DDF will
> think about this because I'm still confused about his portion with regards
> to Un tuned duplexes.  But I would like to hear more of what he has to say
> about it.

Simply that the front duplex segment should be designed so that it does
not allow vibrating energy from the speaking portion of the string to
bleed into the duplex segment in the first place. Most of the energy
that ends up there is lost into the plate and in itself. It is true that
a certain small amount does make it back into the speaking portion, but
on balance the design creates far more problems than it is worth. The
losses exceed the gains.

There is no benefit to be had at all for attempting tune the back scale.
The point here is that you need a system designed to allow the bridge
(and the soundboard) to move.

--ddf