Robert Conrad, Registered Piano Tuner/Technician, Tucson, AZ

FAC Tweak: The “A” Multiplier Default

The “A” Multiplier Default for an FAC tuning is 1.0.   That is the default.  Unless altered either manually or by using the MENU feature in the SAT IV to change it, the A multiplier Default will be 1.0.

The need for this tweak has been around for some years now, but it should be used whenever using an FAC tuning.

Without using this tweak, when using an FAC tuning, A4 will end up being slightly sharp of A440.   The exact amount will vary depending on the piano but Jim Coleman Sr. came up with an easy fix some years ago that works quite well.

Jim figured out that if he multiplied his measured A number by .8, the FAC tuning would hit A4 almost practically perfect!  If the FAC’s  A number was 10, if he entered it as .8, his A4 would be @ A440.

This works so well, it was incorporated into the SAT IV’s MENU.

So, those of you with SAT IV’s should go into the MENU and set the ‘A’ Multiplier Def to .8 instead of 1.0.  Do it today, right now.  Your ‘A’ will be much better off, or should I say much better on?

The instructions are found in the SAT IV instruction manual.

But I will give them here as well:

To set the A Multiplier Def with the SAT IV:
After tuning it on, while it’s in calibration, press and hold the BluShift button until it goes into the MENU.
Use the Note Up button to step up to the option that says A MULTIPLIER DEF.
Now press BluShift and it will show you the setting.   You want to see a .8 instead of 1.0.
If your SAT says 1.0, press the Note down button so that 0.8 is in the window.

When .8 is in the window, press the BluShift button again and you should see ‘MENU’.
Now press Note up once and you will see EXIT.
Press BlueShift to exit the MENU and your SAT should now be back in calibration.

Press Tune and you’re done and your SAT is now set to the .8 default.
From now on your FAC tuning’s A4 will be much closer to A4 @ A440.

Manually using the “A Multiplier Def” on the older SAT models:

For those doing this tweak manually, just measure your A number as usual, but before storing it, multiply it by .8 and store that number instead.

This can be another use for the calculator in your phone!   For many, multiplying 9.4 x .8 or whatever may be easier on a calculator.

For example, if you measure the A4 number as 10.0, store .8 instead.
If you measure the A number @ 9.0, store 7.2 instead  (9.0 x .8 = 7.2).
If you measure the A number @ 9.4, store 7.5 instead  (9.4 x .8 = 7.52).
If you measure the A number @ 11.3, store 9.0 instead  (11.3 x .8 = 9.04).

This lower A4 number also tightens up the temperament area as well.

Use the  .8  ‘A’ multiplier as your default A number, either doing it manually with the older SATs or automatically with the SAT IV.

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