stability of pitch raises

[Z! Reinhardt]

One person you might want to talk to is Doc Sanderson (Dr SAT himself) at
Inventronics.  He has done research on the effects of doing a pitch raise
"piecemeal" (start with a temperament, tune single strings, then pull in
unisons) versus "brute force" (crank all pins from one end of the piano to
the other).  If I remember correctly, he has found that the "brute force"
method [my terminology] results in more stable tuning at pitch using a
smaller overpull than would be necessary to do a "piecemeal" pitch raise.
He may have an explanation for this phenomenon.

It's true.  As someone who used to do pitch raises by ear and now does them
with an SAT, I have found that I can get a lot more done a lot closer to
pitch in much less time than doing it aurally.  Furthermore, the overpull in
the SAT at 25% is too much except in the 5th and 6th octaves, while the
aural pitch raises required an overpull of 35% or more in some sections.
Finally, the pianos do stay closer to pitch a lot longer afterwards after a
"brute force" pitch raise than they ever did after a "piecemeal" pitch
raise.

Z! Reinhardt  RPT
Ann Arbor  MI
diskladame@provide.net


----- Original Message -----
From: <Tvak@AOL.COM>
To: <pianotech@ptg.org>
Sent: Wednesday, August 29, 2001 9:56 PM
Subject: stability of pitch raises


I do all my pitch raises using RCT, so I end up very close to pitch after
the
first pass.  If the piano is 50 cents flat or more, I have always warned the
client that a pitch-raised tuning is a less stable tuning, and that their
piano may need another tuning in 3 or 4 months.   Rarely do they actually
call me in 3 months.  Most often I come back in a year...OR TWO, and I am
usually surprised at how well the piano has stayed in tune.  Not that the
piano doesn't need a tuning, but it's tolerable enough that I can understand
why I haven't been called back sooner.  I suppose it's possible that the
piano did all its drifting in the first 3 months, and just stayed there, but
I'm starting to wonder about the conventional wisdom that a pitch-raised
tuning is less stable.

Could it be that the use of the RCT negates the instability issue by virtue
of getting the piano so close to pitch after the first pass?

Any thoughts?

Tom Sivak