16
15.
Every two or three notes below A3 aurally check the sound of the octave to make sure you do
not have too much stretch in the sound of the octave. The minor 3rd-M6th test is good to use
(if the min 3rd is slower than the M6th, the octave is stretched beyond the 6-3 relationship). If
the octave is becoming too wide, you can decrease the DOB .1 bps at a time about every 3 or
4 notes if desired.
16.
Continue tuning upward from A4, tuning unisons as you go. Place 3/4" rubber wedge between
L and Center strings and TUNE R string. Move wedge between C and R strings and TUNE L
string. Move wedge to between the L and C of next note and TUNE the center string by ear to
the previously tuned L and R strings. To insure stability, play each string at least 4 or 5 times
firmly at the stopped display position. Then when all three strings are sounding together, you
can get an idea how solid the unison is. Any tendency for the three strings to be at a lower
pitch than the single strings can be corrected with the tuning of the middle string aurally.
17.
As soon as I get to F5, I can check the relationship of the double octaves below and see that
there is a slight spread of the double octave and that the octave-5th is almost pure. By the
time I get to C6, I can see the relationship of the double octave, the single octave-5th, the
double octave-5th, and I can listen to the parallel 17ths progression. At F6 I can play the note
F3 to see how the triple octaves are matching up. If I notice the triple octave test shows the
dots moving counterclockwise, I can reign in the DOB a little bit, .1 beat at a time, every two
or three notes.
18.
From C7 to C8 each individual string is tuned with the SAT. The finished unisons can be
listened to for clarity sake and correction if necessary. In this area, unisons are usually better
tuned with the SAT than tuned strictly aurally. In this area, I can do all the tests mentioned in
18 above. If the triple octave is fairly close to my setting, the single octave-5th will usually be
a little wide while the double octave-5th will be dead-on or slightly narrow. In this case, the
quadruple octave will usually be a little narrow. I can tell all of this just by watching the drift
of the LEDs as I play the various test notes below.
19.
TUNE the unisons aurally from the lowest plain wire notes through A4. Let the SAT follow
you so that you can detect any correction, which may be necessary after the firm playing of
the unisons. Play repeatedly about 1 to 2 blows per second. Listen to the interplay of the
highest partials you can hear and bracket in the unisons as closely as possible. On pianos,
which I know to have little or no single string beating, I may elect to tune all 3 strings with the
SAT.
20.
Bass tuning on 7' or 9' pianos works very well with the regular measured FAC tunings.
However, for medium or small pianos I like to stick to the pure 6-3 type octaves where the
minor 3rd test equals the M6th test as complementary intervals of the octave. To achieve
this, I use negative DOB like this: For example if I am tuning B2 to B3, I play B3 (already
tuned) while the SAT is on B2. B3's 3rd partial (F#5) will probably be moving clockwise. I
select enough negative DOB to cause the LEDs to stop, then I tune the B2 to this setting
(remember that it is necessary to press note up then note down to get the new DOB applied). I
felt strip out the Bass section while tuning these octaves. After tuning 3 or 4 notes this way, I
will recheck the 6-3 octave match. If when playing the upper note of an octave to be tuned, I
should notice the LEDs drifting sharp again, I will invoke additional negative DOB. When I get
to the lowest few notes of small pianos, I may allow the upper note of the octave to show a
slight drift in the clockwise direction to add a little more stretch (these notes always sound a
little sharp anyway).
21.
I TUNE out the unisons after pulling out the felt strip. I try to make the best compromise
possible in the unisons. I play the notes repeatedly as in the aural unisoning of the midrange,
looking for that most solid sound at impact.
PS This looks and reads much more difficult than doing it. Its advantage is that you begin tuning
immediately and you need to store only 1 measurement in the process. The DOB adjustments
are made "on the fly” and very few are necessary. JWC
USING THE A4 STRETCH NUMBER MULTIPLIER.
There is a method for measuring the A4 stretch number, which is a direct method of tuning A4 to
the fundamental. The newer style described above tunes A4 once instead of tuning A4 for
measuring the stretch number and a second time for the FAC tuning.
Temporary changing of the A4 multiplier:
1)
Turn on Accu-Tuner
