Getting the A right with FAC

[k.swafford@genie.com]

>>Dear Ed,
>>
>>How can one "plug their offset in BEFORE you put an FAC tuning into
>>memory" when one does not know the size of the offset until one has
>>calculated the FAC tuning?  Must you calculate the FAC twice?
>
>>Phil
>
>1. do an fac
>2. tune a4
>3. check to see if "offset" is necessary.
>4. turn SAt off
>5. turn sat on
>6. adjust offset up or down using cents cents.
>7. Tune A4
>8. check A4 and if necessary cyle through step 6 & 7 until "correct"
>offset
>has been found.
>9. set "correct" offset.
>10. do fac
>11. Store fact
>12. tune piano pitch correcting as necessary.
>
>Regards,
>Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T.

     It is possible to correct an FAC tuning so that the fundamental
of the piano's A4 will be dead on 440, allowing the SAT's pitch raise
function to target the correct pitch level.  It is not necessary to go
through the FAC measurement procedure twice, however.  Below are
Bob Conrad's step-by-step instructions, reprinted from the November
1993 Kansas City Beat, the newsletter of the Kansas City Chapter PTG.

     One note: the instructions at the end mention manually removing
the SAT's offset after storing the FAC tuning at the corrected level.
My SAT, and I presume other late model SAT's as well, remove the SAT's
overall offset automatically when the corrected FAC readings are
stored in a page of memory.

Kent Swafford

___________________________________________________________________


The Accu-Corner
Robert Conrad

Getting Your "A" Right, Part I

I. Getting Ready

These instructions assume you already know how to:

1.  Turn on the SAT.

2.  Calibrate your SAT to it's most accurate calibration possible.

3.  Get out of and/or into the calibration mode.

4.  Know how to change pages in your SAT.

5.  Measure the FAC numbers for the piano being tuned.

6.  Know how to store the FAC numbers to the page of memory you
selected.

     Beginning from a cold start and with your SAT accurately
calibrated, you have measured the FAC numbers, and you know what page
(in the SAT) you want the tuning to be on.
     For this example, let's say the FAC numbers are 10, 9, 8; and we
will use page 30.

1.  Store the FAC tuning to page 30.  (After about ten seconds the SAT
should show: A0 * 30.)

2.  Using the octave up button step up to A4.  (It should now show: A4

3.  Press the tune button.  (SAT: A6 * 11.2) 4.  Press the octave down
button twice to A4, and adjust the cents buttons to get 0.0 in the
cents window.  Your SAT should now show: A4 * 0.0.

Review:  You have measured the FAC numbers and have stored the FAC
tuning to Page 30.  You are now in the tune mode.  If you press the
tune button again, nothing should change ( A4 * 0.0 ).

II.  Determining the amount of the offset:

1.  Using your tuning hammer, tune one string of the note A4 on the
piano to stop the lights on the Accu-tuner.  A4 * 0.0  (In the tune
mode, with accurate calibration, you have just tuned the 1st Partial,
the "fundamental," of A4 to 0.0 cents or to 440 Hz.)

2.  Take the tuning hammer off of the tuning pin.  A4 * 0.0  (This
step is optional, of course, but it is important to know that, for
now, you are finished with the tuning hammer.

3.  Press the MEM button.   A4 * 30  (This puts you back onto page 30
in the Memory Mode where you just stored that FAC tuning.)

4.  Press Note Down once ( G# * 10.1 ) and then Note Up once to get to
A4.  A4 * 11.2  (You are still in the Memory Mode.)

5.  Now play the note on the piano you just tuned to 440 Hz in Step 1
(that one string of A4), and observe the light's rotation.  (If there
is no rotation, no offset is necessary.  But if there is some
rotation, you will need to offset the FAC tuning to get your "A"
exactly right.  You know the A4 on the piano is at 440 Hz.  You must
now tune the FAC Tuning to the piano.)

6.  Stop the lights using the cents buttons on the Acuu-Tuner.  (For
example, let's say that when you stop the lights with the cents
buttons, the cents window shows 10.3.  The FAC Tuning, generated from
the 3 FAC Stretch Numbers (10,9,8), calculated A4's 4th partial to be
11.2 cents.  We know we tuned A4's fundamental to 440 Hz back in Step
1.  And now, after measuring where the 4th partial of A4 really is
when the fundamental is at 440 Hz, we find the fourth partial should
be at 10.3, instead of 11.2.  The difference is -.9 cents.  The FAC
tuning (in the SAT) needs to be lowered (offset) by .9 cents to end up
with the fundamental of A4 at 440 Hz.)


III.  Offsetting the FAC Tuning and Re-Storing it to a Page of Memory

1.  Press TUNE.  ( A6 * 10.3 )

2.  Use the CENTS buttons to show -0.9 in the cents window.  ( A6 *
-0.9 )

3.  Press and hold the SHIFT button, then press and hold MSR/RST
button.  Release SHIFT button, then release the MSR/RST button. ( - A6
the "-" mark to appear on the left in the Note window.)

4.  Now you want to Re-store (i.e. store again) the FAC Tuning (but
with this offset):  press and hold STRETCH, press and hold MEM,
release STRETCH, release MEM.

5.  In about 10 seconds your SAT should show:  ( - A0 * 30 ).

6.  The next thing you need to do is clear the offset.  Go into
calibration mode by pressing and holding SHIFT and TUNE buttons for a
second or two.  ( A4 * 0.0 )

7.  Press TUNE.  ( A4 * 0.0 )

8.  Press MEM.  ( A4 * 30 )

9.  Use the octave up button to go up to A4.  It should now say A4 *
10.3.

10.  Now you are ready to pick up your tuning hammer and tune the
piano.