[CAUT] Re: Temperature and pitch

[David Ilvedson]

It's so true...during the Ballet season here in SF, I'm tuning the concert piano (Yamaha CFIII) everyday  before the performance in the afternoon.   I've sat down at piano and been fine tuning when I feel a draft from the back of the Opera House (moving sets in and out )and the darn piano went sharp a couple of cents right in front of my eyes/ears.   I just continued with the tuning but only brought in the unisons and it was soon back to pitch after they closed the doors.   It is pretty amazing when that happens though.   I'm glad to hear that sunlight on the strings will cause the pitch to go flat.   Many times I've had to prop up pillows and whatever to keep the sun off strings in a heavily windowed music room.   

David Ilvedson



----- Original message ----------------------------------------
From: James Ellis <claviers@nxs.net>
To: <caut@ptg.org>
Received: Wed, 02 Mar 2005 17:50:47 -0500
Subject: [CAUT] Re:  Temperature and pitch


>Ed,  

>The strings go sharp when they are cooler than the plate, and flat when
>they are warmer than the plate.  I happens fast - a matter of a very few
>minutes - even seconds if there is a draft.  If the piano has been
>subjected to a major temperature change, wait a few hours until everything
>in the piano has come to the same tempterture, and it should be back on
>pitch.  The cast iron plate and the steel strings have similar temperature
>coefficients.

>If this is what the instructor's problem is, it should not happen if she
>leaves the piano closed.  I wouldn't recommend blowing a hair drier on the
>treble strings unless you are just doing it as an experiment.  But if you
>do, you should hear immediate results as the strings go flat.  Take the hot
>air away, and they will slowly return to pitch.

>You probably read my account about that problem I had 50 years ago when the
>instructor would come into a sweltering hot steamy room early in the
>morning, and open all the windows when it was cold outside.  That will do
>it every time.

>But in your case, to make the treble strings go objectionably sharp
>relative to the remainder of the piano, it would take a cool draft just on
>the treble strings only.  Good luck finding out what's doing it, or else
>what makes her think it's happening.  Some people's ears change with the
>time of day.  I know.  Mine do, and I make allowances for it.

>Jim Ellis

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