temp change=how much pitch change?

[John M. Formsma]

Marcel Carey wrote:
> Hi John,
>
> It's pretty unpredictable but in a way it is predictable. The thing is
> that with temperature change, longer strings elongate more than short
> strings. So what I find is the pitch will move more in the tenor section
> than in the treble. What I like to do (which isn't always possible) is
> to tune after the lights have been on for a while. If not possible, I
> might leave the piano a tad sharp in the tenor and not stretch my
> octaves as much as I normally would. But I will come back after dress
> rehearsal and re-tune to clean octaves and specially unisons.
>   

I was tuning the tenor a bit sharp also, but not too much. Since I 
didn't know how much pitch drop there might be under the lights, I was 
fairly conservative: more pure 4ths, but not so much that the 5ths were 
beating too much. Also, I set a conservative temperament this time. 
Normally, I go for nearly pure 5ths, but this time the temperament 5ths 
were more like the "2 beats in 5 seconds." Maybe it all added up to 
produce a good end result. I don't know, 'cause I didn't stay for the 
performance.

I tell the people every time they call me that the piano needs to be on 
the stage with the lights on. So I was expecting it to be so yesterday, 
but it wasn't. Maybe after the 10th time something will stick. <g>
> But I say OK for pitch, but for unisons, everybody can hear them
> howling. Before a concert, if you have time at all to clean the unisons,
> you should be fine.
>
> Marcel Carey, RPT
> Sherbrooke, QC
Yeah, I was figuring on doing just that since the piano was stable 
before rehearsal. But I ended up doing a small pitch raise and tuning 
before the performance. Oh well, a fellow can only do so much, and I did 
as best I could. So I'm satisfied it was the best it could be under the 
conditions I was given to work in.

Thanks for the post.

JF