the A floats

[Dave Nereson]

----- Original Message ----- 
From: "Richard Moody" <remoody@midstatesd.net>
To: "'Pianotech'" <pianotech@ptg.org>
Sent: Sunday, August 29, 2004 1:03 AM
Subject: the A floats


> >From Bod Davis,
> . . . . .   the piano dropped  four cents
> in a full house and then rose four cents in the dark.   <<

    You'd think that with all the people breathing, adding humidity and
warmth to the air, allowing it to hold more moisture,  that the piano would
go sharp, then go back flat when the theatre was dark.  But I suppose the
warmth of the stage lights heating up the strings and making them go flat,
especially if the lid's removed, is a stronger force than the temporary
humidity during the concert from all the breathing humans.
    If the air conditioning is on during the concert, its drying effect
could, I suppose, counteract the humidity added by the crowd.  But is the
duration of the concert a long enough time for a soundboard to gain or lose
enough moisture to affect the tuning?  I understand the board loses moisture
much slower than it gains it.
    I've never seen a piano go sharp by much, if anything, on a rainy day.
But several days of rain can affect it.  What's the main culprit in causing
the tuning to drift in a concert situation -- the humidity or the
temperature?    --David Nereson, RPT