SAT I & II helps

[Jim Coleman, Sr.]

To Hazen Bannister and others:

I have written a couple of articles in the Journal back in '97 in regard 
to stretching the center octaves more by altering the A4 stretch number.
The articles explain the math necessary, but in general, you can get more 
stretch by adding perhaps .5 cents to the measured stretch number for A4.
After you do this, you can play the tuned A4 while looking at the A3 
setting of the SAT. If the LEDs are moving about two lights per second, 
this means that you have an octave spread in which an F3-A4 M10th will 
beat about 1/2 bps faster than the F3-A3 M3rd. There is only one caution:
When you get up to C5, you need to add offset to the SAT by the same 
amount which you added to the A4 stretch number.

FAC tuning usually spreads the Bass a little too much for small pianos 
since they were originally computed to satisfy Concert Grands (and they 
do). So one can lower the stretch number for the F3 and avoid having to 
do the direct interval tuning of the Bass which Farrell has mentioned.
However, it might still be well to do a little direct measured tuning
around B2 and down a little ways because this is where the SAT starts 
listening to stretched 6-3 type octaves instead of stretched 4-2 type 
octaves. As an example, when tuning a GH1 Yamaha grand, it is good to
tune the B2 by noting first the deviation values of C3 and C#3, then
placing the SAT into the TUNE mode before going to the B2 so that you 
can estimate the lowering of the B2 by the same additional amount as was 
used between the C#3 and the C3 in MEM mode. This will guarantee a smooth 
transition into the upper Bass from A#2 on down a little. After a few 
notes into the Bass one can then revert back to the MEM mode using the 
FAC provided curve.

One can then utilize the direct tuning mode, but keep the curve more or 
less even by putting in a little positive offset whenever playing 
the upper note of an octave shows the LED rotation tending to move in the 
sharp direction while the SAT is set on the lower note of the octave.
By using a little positive offset, this will shrink the 6-3 octave (ie 
raising the lower note of the octave) just a little from the normally 
stretched 6-3 octave which FAC produces.

Some people may prefer more stretching in the Bass than the FAC provides 
normally. This can be accomplished by gradually applying more and more 
negative offset as you go along downscale. I do this when tuning 
A Bosendorffer Imperial, but never on a small piano.

Jim Coleman, Sr.