[pianotech] pitch changes

[Ron Nossaman]

On 2/25/2013 7:16 AM, Marshall Gisondi wrote:
> Hi William
> you wrote
> Yes, Marshall, the pitch of a piano does
> go sharp when the temperature rises, or goes flat when the temperature
> drops.
> You understand, of course, only if the temperature in the room in which the
> piano is goes up or down. The pitch also goes up or down depending on the
> humidity level in the room.



> Yes this is basic.

Except it's still backward. Raise temperature, pitch drops. Don't 
memorize it, understand that strings expand with rising heat, which 
lowers tension, therefore pitch. Eventually the plate expands too, and 
brings the pitch back to about where it was, but it takes much longer 
than the string reaction.

Raising humidity raises pitch, but humidity based pitch changes take far 
longer, days, than temperature related changes.


>I was commenting on this because someone posted if I
> read correctly that the pitch goes down when the temp goes up.  Unless I
> was reading incorrectly.

You read correctly, and the information posted was and is correct for 
short term changes.
Ron N