temp change=how much pitch change?

[John M. Formsma]

Thanks for this, Diane. Good stuff, especially about the graphs. People 
can understand better when they're looking at some real data.

One thing I didn't understand is the following: "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! "

I don't follow why you'd tune it 4¢ flat if it's at the temperature it 
was tuned the previous night. Could you explain?

JF

Diane Hofstetter wrote:
>
> 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
>
>
>
>