temp change=how much pitch change?

[Diane Hofstetter]

John asked:

What do you guys do? Do you not worry about where the temperature is? If you 
think it will be different at performance time, do you set the pitch 
accordingly, and hope it changes in your favor? Or do you simply tune it to 
A440 and don't worry about it?


What we did was:
Measure, measure, measure.  Get to know the piano.  Do more tunings than it 
needs in the beginning until you know that piano.  Get to know it's 
conditions. Get to know the people who have some control over it---become 
their friend!  (It may be the janitor.)

Work out a plan together with those who control the piano's conditions (it 
has to be a plan that works for both of you) , and a contingency plan for 
when that still doesn't work, for whatever reason.

My partner and I tuned a Baldwin SD-10 for almost 20 years.  Did graphs of 
the tuning before each tuning.  Measured temp & RH before every tuning.  
Measured the same at concert time.  Adjusted procedures until we knew what 
made it stable.  Piano had three 25 watt DC rods, a dehumidifier tank and a 
cover, but the conditions in the "auditorium" were almost like it was 
outdoors.

The only ways to have that piano at A=440 at concert time, were either to 
tune it at concert time the night before and have them keep the heat on all 
night (usually they don't), or to tune it in the afternoon, after the 
auditorium warmed up and tune it 4cents flat!

Good luck with your concert venue!
Diane