[pianotech] pitch and temperature

[Gene Nelson]

Thanks everyone,
I was trying to come up with a chapter technical on the subject.
Possibly an approach from co-efficient of expansion for steel piano wire, isolating for the one thing that moves the fastest and possibly the most? The math is beyond me.
My challenge was a couple years ago in the winter, a loaner sat on the moving van in freezing weather overnight, brought on stage indoors in a warm theater and I had about an hour to work with it.
Gene

  ----- Original Message ----- 
  From: PAULREVENKOJONES at aol.com 
  To: pianotech at ptg.org 
  Sent: Sunday, January 09, 2011 6:08 PM
  Subject: Re: [pianotech] pitch and temperature


  Contact Jim Ellis.

  Paul

  In a message dated 1/9/2011 3:31:27 P.M. Central Standard Time, hgreeley at sonic.net writes:

    Hi, Ron, Gene,

    At 01:22 PM 1/9/2011, you wrote:
    >On 1/9/2011 2:28 PM, Gene Nelson wrote:
    >>Curious if anyone knows of a reasonably accurate method to predict pitch
    >>change in a piano based on temperature change?
    >>Gene Nelson
    >
    >Gut Nichols had a system he liked, but I don't 
    >remember his numbers off the top. The problem is 
    >that it's time dependent. It might change 2¢/°F 
    >on a minute by minute basis under stage lights, 
    >but in the long run it doesn't seem to make a 
    >tremendous difference. Short term, the strings 
    >react first. Give the plate time to catch up, 
    >and the overall difference isn't that much. I've 
    >tuned in homes where the tuning changed back and forth as the furnace cycled.

    That's kind of what I remember, too; but it's been a while.

    From a performance standpoint, the problem is 
    further complicated by the ways in which 
    orchestras play in tune or not, most often, the 
    latter.  I do agree with that things do tend to 
    catch up over time, so am always hopeful that 
    whatever main use of the instrument is after intermission.

    Has anyone ever done any substantive research on 
    this?  It seems like the potential variables could be pretty daunting.

    Best.

    Horace 
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