Variation of temperature

[BobDavis88@aol.com]

>I am looking for precise datas about pitch drift caused by a temperature
>change.  For example, how much cents does the pitch increase if the
>temperature drops by five degrees?  (which could easily happens when you
turn
>on the air conditionning)

Michel,

You're right that cycling of the heating or air conditioning system, sun
coming through the window, stage lights coming on, etc., can throw our best
work awry, even while we are tuning!

I'll bet that if you posted a little more information about why you're
asking, someone on the list could help even beyond the answers you've already
gotten. Pitch drift due either to temperature or humidity is a function of
the scaling of the note in question, its position in the scale and many other
factors. No two notes will react exactly alike, so "approximate" is possible
while "precise" is not. For instance, a note under low tension in the middle
of the long bridge will move farther than a high tension note higher in the
scale.

Regards,
Bob Davis