Brian, that is an OK idea if the piano that you are tuning is a piano that is in the ball park height wise (hopefully, somewhere scale wise as well). Stay away from spinets with this machine especially as Yamaha, to my knowledge, never made one. So there is not anything even close for them on the PT-100. Your mentor probably wouldn't let you practice on one at first anyway. The stretch in the bass on many spinets can get dramatic to make the tuning sound good. The PT-100 tunes the bass narrow to me anyway, so this would be even more of a problem on many spinets. But, to more directly answer your question on using it in the temperament area only, that is about the only place you can get away with using it, and again, on some pianos. I have found that it is "acceptable" in the treble/high treble on some pianos. Bottom line here is as soon as your ears (aural checks, tests) hear a discrepancy with this machine go with your ears. Good luck - Devlon
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