[CAUT] temperature and pitch

[Fred Sturm]

On Dec 16, 2009, at 10:05 PM, Ron Nossaman wrote:

> If you're trying to make a case for humidity change here, be advised  
> that the pitch goes sharp as the strings cool from the slightly  
> elevated temperature from the heater bars under the cover.


No, I'm not making a case for anything, just trying to be sure I  
understand the circumstance. I think that the confined system you  
describe would obviously lead to a build up of moisture and heat, as  
you describe, with the cycling of adding humidity and then heating to  
try to reduce it. Seems a little counter to the design of the D/C  
system. I remember reading about the 9 part system for the back side  
of uprights, and how they would include a back cover, but it needed to  
be open by some amount to allow for exchange of air. IOW, air exchange  
is part of the way the system is supposed to operate.
	I don't have any systems in pianos with floor length covers, so it is  
an unfamiliar animal to me. I don't think I would be inclined to  
recommend it.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu