Ed, The strings go sharp when they are cooler than the plate, and flat when they are warmer than the plate. I happens fast - a matter of a very few minutes - even seconds if there is a draft. If the piano has been subjected to a major temperature change, wait a few hours until everything in the piano has come to the same tempterture, and it should be back on pitch. The cast iron plate and the steel strings have similar temperature coefficients. If this is what the instructor's problem is, it should not happen if she leaves the piano closed. I wouldn't recommend blowing a hair drier on the treble strings unless you are just doing it as an experiment. But if you do, you should hear immediate results as the strings go flat. Take the hot air away, and they will slowly return to pitch. You probably read my account about that problem I had 50 years ago when the instructor would come into a sweltering hot steamy room early in the morning, and open all the windows when it was cold outside. That will do it every time. But in your case, to make the treble strings go objectionably sharp relative to the remainder of the piano, it would take a cool draft just on the treble strings only. Good luck finding out what's doing it, or else what makes her think it's happening. Some people's ears change with the time of day. I know. Mine do, and I make allowances for it. Jim Ellis
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