tape

[Jim Coleman, Sr.]

To Les Bartlett:

In the video tapes which I did recently in comparing the RCT, TunelabPro 
and SAT III I was demonstrating the way I like to tune. Let me try to 
express this in words which may be helpful to others even though they do 
not have the video.

The better tuners which I know about try to stretch the center octave so 
that a M3rd-10th test will show the 10th as being about a half bps faster 
than the M3rd, An example would be F3-A3 is 1/2 bps slower than F3-A4.
This can be viewed on an ETD as approx a 1 cent difference shown at the 
location of the 4th and 2nd partials of the octave A3-A4 at A5. As one 
maintains this spread of the octave the 5ths are slightly slower 
and the 4ths slightly faster. This improved solidity of the 5ths helps 
the general sonority of the piano. Some tuners may be consistent is 
having the stretch of the octave equal the speed of the 5ths. One could 
refer to this as "equal beating" which has an advantage in historical 
temperaments with other intervals.

As I proceed on up the scale, an attempt is made to keep the octave- 
5ths very quiet. This is done along with attention to the stretch of the 
octave and later the double octave when that range comes into play. By 
the time the 6th octave is reached, the double octave-5th comes into 
play. It's OK if this interval is slightly compressed and the octave-5th 
is slightly expanded. This will usually give a wide double octave and a 
slightly compressed triple octave. For an example, when C6 is to be tuned
one can touch the C5 which will show an expansion of the octave when 
viewed on the ETD. When the F4 is touched, it will show a slight 
expansion of the octave-5th on the ETD. When the C4 is touched, it will 
show a slight expansion of the double octave. When the F3 is touched, it
will show a slight compression of the double octave-5th. When this much 
stretch is used, the triple octave will be fairly close to being in tune.

If one does not do the stretching in the center of the piano, there is no 
way that the triple octaves will sound reasonable without having to do 
extreme sharpening of the single octaves and the double octaves.
In the video you can see me checking all of these intervals quite rapidly 
just to hear the solidity or similarity of those intervals. The 10th and 
17th will progress evenly as one tune up the scale.

In the Bass tuning portion of the video, since this was a medium sized 
piano, a choice was made to keep the bass octaves as clean 6-3 type 
octaves. An example of a pure 6-3 octave is the minor 3rd-Major 6th test.
(ex. C2-Eb2 minor 3rd equals in beat rate Eb2-C3 Major 6th and can be 
viewed at the location of C5 on an ETD.)

If I were tuning a larger piano, I might give more attention toward 
matching the 8th partial of the lower note with the 4th partial of the 
upper note of an octave (8-4 match). An example of this type of match 
would be the equal beat between the minor 6th and the M3rd such as:
C2-Ab2 m6th equals Ab2-C3 M3rd. This is simple to see on an ETD by 
setting the ETD to C5 when tuning the C2 to C3 octave.

On a much larger piano (9') it is good to stretch the octave even more
such that a M6th equals a minor 3rd as: C1-A1 equals A1-C2. On an ETD 
this relationship can be seen with the ETD set at E4 where one is 
listening to the 5th partial of C2 and the 10th partial of C1.

As one does all this octave matching evenly, the 10ths and 17ths will 
remain fairly even on any decently scaled piano.

Jim Coleman, Sr.