[CAUT] temperature and pitch

[Ron Nossaman]

Fred Sturm wrote:
>But I think my 
> earlier assessment was correct: the D/C produced heat was not a 
> significant factor.


I know of one instance where it is most certainly a 
significant factor. A church with four pianos. A C-6 Yamaha, 
and 3 P22s. The grand and two of the verticals with 
Dampp-Chasers, and covered. The grand isn't much problem. When 
I uncover it, it takes five or ten minutes or so to settle 
down while I strip mute and set up. Even so, I have to 
backtrack over the temperament probably three times before it 
quits drifting. The rest of the tuning goes well. The uprights 
are different. When I pull the cover off and open the lid, a 
startling amount of warm moist air pours out the top. I have 
to get them uncovered and opened up 15-20 minutes before I 
start to tune or I'll be chasing that time during the process. 
After the strings cool to nominally room temperature, they are 
very close to on pitch and tune easily and quickly. I worried 
about the atmosphere under those covers, but neither piano has 
showed any indication of discomfort in close to five years 
now, so it doesn't seem to be a problem. I typically tune the 
uncovered upright first, going to uncover and open one of the 
others half way through the tuning, and again for the next 
one, and again. The unregulated piano is always wildly off 
pitch from humidity effects, the others only very slightly 
until the strings cool.

Ron N