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When the Accu-Tuner creates an FAC tuning the program creates the tuning and sets the partial
in the following manner. In the bass the Accu-Tuner is listening to the sixth partial, in the
midrange the Accu-Tuner is listening to the fourth partial, treble the second partial and the upper
treble the first partial or the fundamental. The FAC partials can be conveyed as similar to a
phone number 664 4211. This is illustrated in more detail in the following table:
OCTAVE
PARTIAL
KEYBOARD
PITCH OF PARTIAL
Octave 0
Sixth Partial
A0
E3
Octave 1
Sixth Partial
A1
E4
Octave 2
Sixth Partial
A2
E5
Octave 3
Fourth Partial
A3
A5
Octave 4
Fourth Partial
A4
A6
Octave 5
Second Partial
A5
A6
Octave 6
First Partial
A6
A6
Octave 7
First Partial
A7
A7
Octave 8
First Partial
C8
C8
You probably noticed that as you tune from the bass up the scale of the piano that the cents
deviation will jump. You may tune the note B 2 on the piano with a cents deviation of plus 1.6,
then step up one note and C3 will have a cents deviation of minus 2.5. The reason for the
decrease in the cents deviation is on the note B 2 the Accu-Tuner is listening to the sixth partial
and when we step up to C 3 the partial changed to the fourth partial and the cents deviation is
lowered to compensate for the partial change.
A QUICK METHOD FOR STORING STRETCH NUMBERS
Another feature of the Accu-Tuner IV is the ability to adjust and store the FAC numbers without
having to follow the entire sequence outlined above. This is helpful in many situations: if the
stretch numbers are already known, it is possible to enter the stretch numbers quickly.
The following procedure assumes the Accu-Tuner is off; it is not necessary to follow every step if
the unit is already in use.
1)
Turn on the Accu-Tuner
2)
Press the TUNE button
3)
Hold down the STRETCH button.
4)
The display will show F3, A4, or C6. The cents will show the current value of the
corresponding stretch number. While holding the STRETCH button use the CENTS up/down to
adjust the stretch number to the desired value.
5)
After the stretch number is adjusted to the correct value, release the STRETCH button
6)
Hold down the STRETCH button a second (or third) time.
7)
Adjust the next stretch number by using the CENTS up/down to adjust the value.
8)
Release the STRETCH button.
9)
Repeat steps 6-8 until all the stretch numbers are entered correctly.
10) With the new stretch numbers properly stored. Select a page in memory, roll over from the
STRETCH to MEM button, which will calculate the FAC tuning and store it to memory.
REVIEWING THE FAC NUMBERS
To review the FAC numbers for a tuning just created or about to be created, use the following
procedure. Hold down the STRETCH button, while held down one of the three stretch numbers
will be displayed. The display will show F3 and show the F3 stretch number. Release the
STRETCH button and hold it down a second time to see the A4 stretch number. Release and hold
