[CAUT] temperature and pitch

[Jeff Tanner]

Hi Fred,
Did you measure RH change as well? Your conditions would probably be 
different, since you guys don't have any moisture in the air out there. See, 
here, you can't answer the temperature question because humidity change is 
so unpredictable. In our situation, you could have a significant change in 
both temp and humidity during the day, and a piano tuned first thing in the 
morning would be out of tune enough that a relatively significant pitch 
adjustment would be necessary in the afternoon. Of course, if you wait to 
retune until the next morning, the piano would be right back where you put 
it the morning before unless you'd had a large humidity swing.  Same in 
reverse, once I started afternoon tunings, if I needed to go in in the 
morning for some reason, the piano would be in a much different place than I 
left it the previous afternoon. All-day recording sessions were the most 
revealing, because they would have to turn off the HVAC. The room would heat 
up from the lights and by noon the piano could sound like a saloon piano and 
need to be tuned twice, really, to restabilize it at the pitch they'd 
recorded at during the morning. They'd want me back the next morning, and it 
was way out of whack again because they'd run the HVAC all night without 
lights.

There were several occasions when the room would be going through a 
noticeable change during my tuning time, and the piano would go out of tune 
faster than you could tune it. You'd want to give up after retuning the low 
tenor the 3rd or 4th time.

Once I got on a schedule of tuning at 2:30, the piano would be much more 
stable for recitals.
Jeff

----- Original Message ----- 
From: "Fred Sturm" <fssturm at unm.edu>
To: "College & University Technicians" <caut at ptg.org>
Sent: Friday, December 11, 2009 4:21 PM
Subject: Re: [CAUT] temperature and pitch


> 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
>
>
>
>
>