A stubborn D?

[Ron Nossaman]

At 06:10 PM 4/12/99 -0400, you wrote:
>The following has been pasted here..it was originally sent to my mentor,
>but i thought I might try this forum and see if any ideas come from it.
>
>Rook
>
>
>Just got done with a Steinway D bringing it down to A=440 from 442..It
>took 2+ tunings to get it to hold at 442..Octaves 5 & 6 were very
>stubborn going up to 442 and coming back down to 440..more than i think
>they should have been.
>
==================================

There's probably more than one issue here. If the long term instability
problem is with individual unisons, It's probably the strings that aren't
rendering through the bearing points keeping the tuner from being able to
tell when the string is set correctly during the tuning. If "a lot of new
wire" refers to individual strings, rather than whole sections, That could
mean that strings broke during tuning, also because of the above condition.
A touch of Pro-tek helps, as has been mentioned.    

If the long term instability is more general, but at specific areas of the
scale, like the low tenor, and octave 5-6, it's likely humidity related.

The difficulty in making pitch adjustments is something different. Like
Newton said, Ds don't like pitch changes. I think it's primarily that
compression crowned, treble diaphragmed board that's the reason behind it.
The balance between the string bearing load and the resistance (springiness)
of the board isn't too well matched in all areas of the scale, and even a
little overall tension change in one part of the scale affects other areas
more than it seems that it should. There's a lot of going back and forth
until everything balances again at the new tensions. You can't fix this
without replacing the board with one of a different design.

In most of the Ds I've checked, the bearing in the high treble is between 2
and 2 1/2 degrees, going down to negative, zero, or nearly no bearing at the
beginning of the low treble section. Immediately on the other side of the
strut, in the high tenor, I usually find something just under 1/2 degree.
I'd be curious to know how this compares with what other techs are finding
out there. I don't think all the Ds I've checked are unusual mutants, but
you never know. Check the crown underneath with a string, rim to rim
parallel to the ribs, in the octave 5-6 area particularly. That's where
compression crowned boards usually go flat first, and that can partially
account for both the pitch change problems, and long term instability in
that area.

Hope that helps... some.
 Ron