I agree it would be interesting, but start with a decent STABLE AT PITCH (A440) piano - not a piano that you just did a 92-cent pitch raise on. Terry Farrell > 1992 01 pitch corrected 92 cents at A4 humidity 40% (including overpull) > 1992 02 floated pitch at 7.5 cents sharp at A4 humidity 47% > > Today? Pitch correction at A4 of 31.6 cents and worst note of 120 cents > humidity 29% (including over pull). > > Total pitch change over 160 months at A4 = 39.1 cents > > My "guestimate" is that for every 5% humidity change A4 drifts 4 cents. > This would give around 14 cents of the pitch change for the humidity > portion. > > Plugging that value in makes the pitch correction at A4 more like 25 cents > in a mere 160 months between tunings, or about 0.15 of one cent per month. > > I have no way to factor in humidity change for the worst note but if we > ignore it then 120/160 =~ 0.75 cents per month. > > I hope more folks will do this sort of analysis and post it to the list--I > found Conrad's data *most* interesting! Particularly that the piano was at > 436.7 on 01/03 and a year later was 436.7 again. Too bad there was no > measurement of room humidity to go with this!
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