Ed Foote writes: > Could the unison, when allowed to sound, be causing more bridge movement, >thus causing the phenomenom of "longer than absolute length" come into play, >showing up as lower pitch? > Perhaps those that want to measure such things could find out if there is >a degree of flattening when two strings are compared to one? And is this >greater or lesser than when the third string is allowed to sound. >( this seems like the sort of project that could use the RCT's >capabilities...??) ....or the TuneLab's capabilities, for that matter. I decided to use the TuneLab program to see if I could verify this pitch drop, and this is what I found. I first selected some notes on a Kawai grand that were the most free of false beats so that a very precise pitch measurement could be made. Taking a hint from Jim Coleman, Sr.'s inharmonicity studies last year, I was very careful to standardize on how hard I hit the note. Then I tuned two strings of a unison (F#3) so that when sounded individually they each produced a totally stopped display. Then I sounded the two strings together. There was a slightly noticeable drift to the left. I had to adjust the offset about 0.4 cents flat to get the display to stop. I repeated this experiment for a number of other strings on the piano. The pitch flattening was anywhere from zero to .4 cents, depending on the note, but on most notes it was too small to measure. Bob Scott Ann Arbor, Michigan Detroit-Windsor Chapter, PTG
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