Alan McCoy wants to know if playing the piano very hard will warm it up enough to make it go flat. Alan, I'd say "no". That's one effect I've never tried to measure. I'm confident the pitch-going-flat thing you experienced was from the heat from the lights. I would expect this effect to be worst in the middle of the piano, and that's what you found. If traumatic blows to a unison caused the strings to warm up enough to go flat, they would return to ambient temperature in a few minutes, and so would the pitch. If the pounding caused a string to neck down at the agraffe, i.e., like just prior to breaking, it would stay that way, and be out of tune with all the others. If the tuning were not solid, which I don't believe, the piano would be all out of tune in a random fashion, not just flat in the middle. No, I'd say it was the heat from the lights that warmed the strings faster than the plate due to their lower mass, and caused a temperature differential within the piano. Jim Ellis
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