[CAUT] temperature and pitch

[Fred Sturm]

Well, this is a special, controlled case. I assume the heat was turned  
down late in the evening, and the piano slowly cooled 10 degrees over  
a period of ten hours or so. This is different from being exposed to  
stage lights and other "during the day" events, as well as  
inconsistent HVAC systems. I thought it was interesting as a predictor  
for questions like "What if I leave my piano in my unheated house over  
the winter?" and the like.
	I also think that my experience has tended to show that once a piano  
has stabilized at a new temperature, it will be pretty much in tune  
with itself. What happens in the meantime is another story - if hot or  
cold air are blowing on it, or lights or sun shining on it, or any  
number of other causes of heat change, things can go pretty haywire.  
Especially the difference between wrapped and unwrapped strings.
	Personally, I haven't had a problem tuning in the recital hall in the  
morning (which is a good thing, since that's when I can schedule it).  
The piano sounds fine that evening, and will hold well for at least a  
few days. Maybe my conditions are different from what yours were.
Fred
On Dec 11, 2009, at 1:58 PM, Jeff Tanner wrote:

> Sorry, I read about half of it the first time, thought I knew what  
> you were going to say, and replied.  I didn't experience the piano  
> tuning moving consistently as you describe.
> Jeff
>
> ----- Original Message ----- From: "Fred Sturm" <fssturm at unm.edu>
> To: "College & University Technicians" <caut at ptg.org>
> Sent: Friday, December 11, 2009 11:17 AM
> Subject: [CAUT] temperature and pitch
>
>
>> This morning I had the opportunity to see a pretty precise picture  
>> of what temperature change does to pitch. I tuned a Steinway A  
>> (old, rebuilt) yesterday in a performance space, and came back this  
>> morning  to tune it again (two night show). The temperature today  
>> was about 10 degrees F lower than yesterday (heat turned down  
>> overnight). The  tuning was as expected for a next day (unison  
>> tweaking), but the pitch  was pretty consistently 2 cents sharp  
>> throughout. Tenor was maybe a  bit less (1 - 1.5), but otherwise  
>> quite consistent. The piano had  obviously cooled down slowly  
>> overnight, and was stable.
>> So there you have a field observation under more controlled   
>> conditions than we usually see, for the record. (I tuned it where  
>> it  was).
>> Regards,
>> Fred Sturm
>> University of New Mexico
>> fssturm at unm.edu
>>
>>
>>
>>
>

Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu