SAT III beating octaves.

[Farrell]

Hello Jim Coleman, you SAT expert you!

I have sat through Dr. & Paul Sanderson class on using the Double Octave
Beat (DOB) feature of the SAT III. I have also read your piece regarding
using two pages of memory (with the SAT II) for tuning small pianos. I
understand the mechanics involved. Regarding the DOB on the SAT III, do you
have any recommendations for fine tuning the DOB setting for the bass on
small pianos? I wonder sometimes whether your suggestion of adding a couple
cents to the F value on one page of memory and subtracting a cent or two to
the other page of memory has any bearing or correlation to the DOB feature
of the SAT III.

I have been doing what I think Dr. Sanderson teaches. What I do is take my
FAC measurement. Mute off two strings of all the A's (or whatever note).
Listen to the octaves in the plain wire sections. Most often, with good FAC
measurements, they will work out just fine. Next listen to the A3 to A2
octave. Usually the calculated tuning will yield a bass note that is flatter
that that the ear likes. So use the DOB to adjust the tuning to make your
ears happy. Check the A2 to A1 octave (sometimes do one or two other
octaves). Usually sound good with the adjusted DOB. OK, so now perhaps we
have made for good octaves across the bass break (Have we? Do you do
anything else? Can this be refined with the SAT?).

Now we need to look at some other intervals across the bass break. The
thirds, fifths, fourths, etc. may need a bit of adjustment to get all in
order. Is there any way to use the SAT to work this out? Or are we just past
anything that we can program into the SAT?

Just trying to get the most out of my investment! Thanks for any input.

Terry Farrell
Piano Tuning & Service
Tampa, Florida
mfarrel2@tampabay.rr.com

----- Original Message -----
From: "Jim Coleman, Sr." <pianotoo@imap2.asu.edu>
To: <joegum@webtv.net>
Cc: <pianotech@ptg.org>
Sent: Tuesday, January 30, 2001 5:53 PM
Subject: SAT III beating octaves.


> Hi Joe:
>
> I saw your comment on the fast beating octaves. You didn't mention if
> the octaves were wide or narrow.
>
> As was shown on this list a while back, you can tell if the octave is
> going to be wide or narrow, by tuning the A4 with the FAC program and
> then changing the octave to 3 while playing the A4 again and checking if
> the dots are going too fast to the right, or if they are going backwards.
> If the dots are rotating one half revolution per second, this will give
> you a 1/2 beat per second wide at the 4-2 octave relationship. If that is
> too much for your personal taste, you can incorporate the Double Octave
> Beat control, say up to -.2 to make the octave beat only .3 bps.  Or you
> could make it a pure 4-2 octave by making the DOB at -.5. This feature
> allows one to control the width of a particular octave even if the
> scaling of the piano is weird. This can be used even on an acrosonic
> spinet to smooth out the beating of the major 3rds across the stringing
> break in the Tenor.
>
> It is important however to measure the inharmonicity of the notes F3, A4
> and C6 accurately.
>
> Here is a method to gain better accuracy: Instead of tuning the F3 to
> the setting F5=0.0 (it is difficult to tune to the accuracy of .1 cent),
> if the F3 is fairly close, adjust the cents to really stop the dot
> rotation. Then hold down the SHIFT button and touch the MSR button to
> reset the SAT to that pitch. Now, you can press UP OCTAVE, use the MSR
> button to slow or stop the dots  while playing the F3 (trim up using the
> cents buttons if necessary for absolute precision). Store this number
> (which represents the difference in cents between the 4th and 8th
> partials of F3) in the usual fashion by holding down the SHIFT button and
> pressing the STO STRETCH button. Utilize the same procedure for
> measuring the A4 Stretch number more accurately, and the same for the C6
> number. Remember that just before calculating the tuning, you must
> recalibrate the SAT to a true A-440 by holding down the SHIFT and TUNE
> buttons to get into the Calibrate mode and then press TUNE to get out.
> Select a page of memory by using the dedicated PAGE Up or Page Dn buttons.
> Now you can do the "rollover technique" (hold down STRETCH, hold down
> MEM, release STRETCH, release MEM). Wait 4 or 5 seconds and you have a
> good tuning for the complete piano. If your personal taste dictates more
> or less octave stretch, then you can use the DOB as described above.
> The DOB can be invoked at any point where you would like the tuning to
> be a little different.
>
> Shakespeare wrote a play "As You Like It". Dr. Sanderson wrote a tuning
> program "As You Like It." I love it. The SAT III does what I want it to
do.
>
> Jim Coleman, Sr.
>