Thanks, Dean, for your quick reply! Dean wrote: > If I understand the tuning you describe correctly, you are tuning a 2/1 > octave between F3 and F4. That is matching the second partial of F3 to > the first partial of F4. I have studied how much tuners stretch the > octaves in different parts of the piano, and this much stretch would be > very VERY conservative. Most aural tuners will set a 4/2 octave slightly > wide at F3-F4, say 1/4 to 1/2 bps wide. That is, the major-third/major > tenth test sh. If I understand your words correctly, that isn't quite what I'm doing. First, I select the scale that is closest to the piano I'm tuning. For example, for a small vertical, I would select the M1 scale. The electronics in the PT100 have already stretched the octaves based on the amount of stretching that would be needed for a M1-type Yamaha piano. That stretching may or may not be best for my piano. Next, I tune F3 with the PT100 set to 0 cents and the tuner set to F3. Then I set the tuner to F4 and measure the second partial of F3. On some pianos, the display for the second partial will be stationary, indicating that the built-in stretch for a Yamaha piano is correct for my piano. On other pianos, the display for F4 will be flat by a cent or so, indicating the built-in stretch is too wide. In this case, I divide the amount of flatness by 12 to get a fractional-cent correction factor for each note. Then, I set the tuner back to F3 and tune F3#, etc. up through E4, entering the correction factor for each note. The result of all this is that I have shrunk the built-in stretch such that 1F3 and 2F3 (is that an acceptable way to denote the first & second partials of F3?) are in tune, and they define the width of my temperament octave. Then I tune 2:1 octaves going from E3 down to A1, and then from F4 up to C8. This procedure is taken from Reblitz. I mentioned above that for some non-Yamaha pianos, the built-in stretch is too wide. I've never tuned a piano in which the built-in stretch is too narrow. Interesting. Since I don't know the algorithm used in the PT100 to stretch the octave, I don't know how closely this would match typical aural tunings. Even though this procedure couldn't be used in the exam on the two octaves you mentioned that have to be aurally tuned, I would be interested to know if this procedure would pass the exam if it were allowed, hence my original post. /Allen Leigh South Jordan, Utah ------------------------------ End of PIANOTECH Digest 214 *************************** .
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