Temperature Change affecting pitch

[Ron Torrella]

What was the relative humidity at 61 degrees? What was it when you figured
the pianos' pitch had stabilized? Raising the room temperature probably
lowered the rh and I'll bet that's what caused the pitch change.

Ron Torrella, RPT
Ypsi, MI

Larry J Messerly wrote:

> Just for my own information, when I came into my store this morning I
> took pitch readings on two grands at 61degrees F. then turned on the
> heating system and raised the temperature to 68 degrees.
>
> The 6' Kranich and Bach dropped pitch 3.2 cents initially and then when
> (I presume) the plate temperature rose ended up 1.6 cents flat of where
> it had begun the morning.
>
> The 5'3" George Steck initially dropped 0.4 cents then continued to fall
> to 1.2 cents from where it had been.
>
> They have not changed any more over the last hour.
>
> No real problem or question here, just thought it was interesting.
>
> Larry Messerly, RPT
> Phoenix/Prescott