Tuning instability question

[John W. McKone]

>In a message dated 96-02-06 09:46:56 EST, you write:
>
>>What I have not been able to determine is when we have 50% in the
>>Winter and 50% in Spring or Summer the pitch will actually be alittle
>>sharper than A-440.  That doesn't make much sense to me, because I thought
>>50%  humidity would be the same, but I have to pull the pitch down to keep
>>it at 440 in the Summer. However, the temperature is higher in the Summer,
>>going up to 72* but in the Winter we average around 68*.  Maybe that is a
>>factor.  Any comments.
>
>Temperature affects the speed of moisture exchange from air to wood. Higher
>temp equals faster exchange.
>
>John Hartman
>
>

Or, more to the point, Higher temperatures allow the air to hold more total
moisture.  Relative humidity is a percentage of the saturation point of the
air at a given temperature, so 50% relative humidity at 70 degrees
represents less actual H2O per unit of air then 50% relative humidity at 85
degrees.

John W. McKone, RPT
Operations Manager
Haugen's Pianos
Twin Cities