temp change=how much pitch change?

[pianolover 88]

<<I don't know what "damp-chaser" means>> You're kidding, right? Humididty 
swings are considerably more threatening to piano tuning stability than 
temperature. But the (full) DC systems stabilize the soundboard and keep the 
moiture content consistent, so surrounding temp and humidity are not as much 
of an issue, than a piano without a DC system.

Terry Peterson



----Original Message Follows----
From: Bob Hull <hullfam5 at yahoo.com>
Reply-To: Pianotech List <pianotech at ptg.org>
To: Pianotech List <pianotech at ptg.org>
Subject: Re: temp change=how much pitch change?
Date: Sun, 11 Feb 2007 20:20:07 -0800 (PST)

I don't know what "damp-chaser" means either nor do I
follow Diane's tune it 4 cents flat.

A chart of temperature, humidity and pitch change
results may be somewhat useful in terms of general
tendencies however, I think that each piano and each
room will react a little differently.  The speed of
the temperature change, the reason for the temperature
change (lights or hvac and type of hvac) all will have
an impact the the amount of pitch change. Also, how
long the piano has been at a previous temperature
makes a difference.  Plate is a large heat sink and
slow to change compared to  strings.
    A specific example in my own customer base includes
a very delicate tuning situation with a Hamburg D in a
small recital hall.  The lights in that room will run
up the temperature quite a ways before the thermostat
will react.  Due to the small size of the room I
cannot allow the temperature to change over .5 degrees
without changing the  pitch level drastically.  I keep
a thermometer on the piano so I can jump up and adjust
the lights to keep the temperature close enough.

Bob Hull

--- "John M. Formsma" <john at formsmapiano.com> wrote:

 > Huh? maybe a little more elaboration.
 >
 > JF
 >
 > pianolover 88 wrote:
 > > Dampp-chaser.
 > >
 > > Terry Peterson
 >




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