Hi Folks, Just some raw data regarding pitch drop due to humidity. I had occaision to pitch correct and tune and then 3 months later install humidity control systems with the smart bar on two Yamaha p2's which are approximately 35 years old. One was allowed to go dry and the other was kept in proper service. Pitch drop on the dry unit was about 16 cents at A4. Pitch drop on the wet was 4 cents at A4. The pianos were in the same very dry building for the entire time with humidity levels being within 1% of each other. Original pitch correction was also very similar. If we assume the wet unit was at 42% (a la DamppChaser) and the dry one was at ambient room levels of 26% and the difference in pitch between the 2 pianos was 12 cents at A4, then we could have the beginnings of a *fudge* formula for floating pitch, and also a fudge to be added into predicting when the next tuning should be sheduled--if there are records of humidity levels kept on a permanent service record inside the piano. 42%-26% = 16% So pitch drop was .75 of a cent for each percentage drop in humidity. I am hoping someone else will do similar measurements. As a side note the worst note flat on the dry piano was 47 cents and on the wet 20 cents; a clear indication that humidity control does help. Regards, Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. Tuner for the Saskatchewan Centre of the Arts drose@dlcwest.com http://donrose.htmlplanet.com/ 3004 Grant Rd. REGINA, SK S4S 5G7 306-352-3620 or 1-888-29t-uner
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