Yet another addendum: It occurs to me this might be a "false beat" issue. False beats occur (putting it as simply as possible) when an individual string produces in excess of one pitch (at any given partial), usually due to termination problems. The SAT, and probably other ETD's as well, can read these discrete pitches. Sometimes you can obtain an initial reading, with some flickering of lights involved, and then, by moving and changing alignment of the SAT, can find both a definite sharp reading AND a definite flat reading. So, depending how the SAT is aligned, it might well be possible to reproduce a different pitch on the same string using the same input. This is why it is so important to eliminate falsity to the extent possible before master tuning, and keep it eliminated when testing (bridge pins can get loose, ride up on bridge pins, etc over time). And another reason why aural verification is an essential redundancy in the test, and why we shouldn't turn off our ears when turning on our machines. Regards, Fred Sturm University of New Mexico
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