strict temperature effects

[Dick Beaton]

Alex...
Right...the strings respond to temp changes much quicker than changes in
plate temp  because of the difference in volume between strings and massive
iron plate.  So when you warm up the strings like from stage lights on Geo
Winstons piano, the pitch goes down about 5 cents by intermission.  When
the piano sits out in the cold overnight and gets the plate really cold, it
shrinks and lowers the tension on all strings so pitch goes down even
though the strings themselves may have tightened up slightly due to temp
change.   In my opinion that is what happened to me...that old upright had
a massive plate...
Dick RPT in Montana
----------
> From: Alexander Galembo <galembo@psyc.queensu.ca>
> To: pianotech@ptg.org
> Subject: Re:  Re: strict temperature effects
> Date: Friday, March 13, 1998 9:27 AM
> 
> If the changes in strings are responsble for the pitch changes with the
> temperature, then  lowereing temerature should highten pitch. If the
lower
> temperature makes pitch lower, it means that the iron frame changes are
> responsible for the pitch changes.
> Right?
> 
> Alex
> 
> >Stephen;
> > This is interesting data. It appears that temperature change is
proportional
> >to mass/speaking length, which I would expect, except for the bass where
the
> >change is not as great as the rest of the scale. Since the bass strings
> have a
> >much greater mass than the plain steel strings I would have thought the
> change
> >would have been greater also..... Any thoughts on this seeming
contradiction?
> >Or am I interpreting the data incorrectly?
> >Jim Bryant (FL)
> >
> >
> Alexander Galembo, Ph. D.
> NSERC-NATO Science fellow
> Acoustics lab, Dept. of Psychology, Queen's University
> Kingston ON  K7L3N6 
> Canada
> 
> Tel. (613) 5456000, ext. 5754
> Fax (613) 5452499
> E-mail: galembo@pavlov.psyc.queensu.ca
> URL   :  http://www.geocities.com/CapeCanaveral/Lab/8779/
> 
>