Oops?

[Warren Fisher]

The other day I was chatting with my customer (big mistake right there),
while setting up a SAT pitch raise of about 125 cents on a small
console. Now I usually do a two stage PR with more than 100 cents
flatness to avoid over-stressing the strings and of course in middle of
octave 4, I get that lovely pranging sound!

So what do I do now, go on and possibly break more strings or reduce the
overset?

I chose the latter.  With the SAT at A440, I continued (No more strings
broke). Another mitigating factor- I normally increase the pitch overset
above the treble break by 15% of the measured flatness, in this case
18-1/2 cents to allow for the lower pitches usually found in the upper
areas of neglected pianos.

Now I have a piano at pitch to D4, -24 cents at A4 and about -15 in the
treble.

Being an old fighter jock, I attacked the biggest problem first; the -24
cents. Starting at D#4, I overset 6 cents and proceeded to the break.
Next I read the flatness in several areas of the treble and averaged to
-16cents. I overset 4 cents (I figured I had overset enough on the first
time through), and went to 88.

What did I have now?  A mess!
It was on pitch through the wound strings, about G3.  All the wire below
D#4 was about 3 cents flat. D#4 to the break was 2-3 cents sharp and
most of the treble was 5 cents or better flat.  Go figure!

Obviously, I don't have a real good mental picture of what was going on
there. A couple of times in the past, I would put extra overset in
somewhere in the pitch raise and for some reason not get back into the
page I was using and would tune a bunch of notes with a zero in the
right window.  When I went back over them with correct settings the
notes were always over-sharp on the next time through. You have to
reduce the overset through the section in error about 10% and then go
back up to the  original overset.

Does anybody have ideas on this?

Warren



--
Warren Fisher RPT
fish@Communique.net
1422 Briarwood Dr.
Slidell, LA 70458-3102