[CAUT] pitch under the lights

[Becker, Lawrence (beckerlr)]

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Barbara-
 
I did a little experiment this past winter with our 1929 S&S D on our big
theatrical stage.  Piano is used as an orchestral and concerto instrument,
and for choral accompaniment.  This is an unusually stable piano, so I
figured I could have pretty straightforward measurements of heat vs. pitch
over time.
 
I measured 6 A's and recorded the temperature measured with a thermo/hygro
unit sitting on the plate.  First I measured on a dark stage, then turned on
the hot lights.  Biggest change was at A3-it lost 2.3 cents in the first 10
minutes, then oscillated up 1 cent and back down .8 cents over the next 2
hours.  Most other A's lost about 1 cent in the first 10 minutes, then
either gradually climbed back up (A1 & A6) or stayed fairly steady (A2 &
A4).  A5 lost 1 cent in 10 minutes, then another .9 over the rest of the
first hour, then came back up .4 over the next hour.  I'll see if it was in
shadow.  The plate increased in temperature at a fairly linear rate over the
2 hours, starting at 69 degrees (F) hitting 71.6 an hour later, and 73.4 at
hour 2.
 
So, what Don said:  Let toast 1 hour until golden brown, then tune.
 
Lawrence Becker, RPT
Piano Technician
College-Conservatory of Music
University of Cincinnati
 
-----Original Message-----
From: Barbara Richmond [mailto:piano57@flash.net]
Sent: Monday, April 25, 2005 9:44 PM
To: College and University Technicians
Subject: Re: [CAUT] pitch under the lights
 
Don,
 
Thanks, for your advice.  That's how I'll do it.  This is my first season
here and so far, the set ups and uses have all been different--so I've been
learning how the piano reacts (no complaints *yet*-- thanks to the head's up
I got in Guy Nichol's class in Nashville).  At my last gig, lighting wasn't
an issue.  Oh, for those days!
 
There's no problem getting the piano pre-heated.  But since it's not first
on the program and will be closed up and sitting off stage for a while, I
wondered how the lag time would affect it.
 
Barbara Richmond
 
PS  How long does it take a hot piano to go back up in pitch?  (Not a joke,
just a question.)
 

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