This is a little chronological presentation of ETDs
The first models (STroboconn, StroboTuners etc.) did not have a good
filtering system. There was much confusion about which strobe band to
watch. Calibration and note to note accuracy was questionable from the
standpoint of piano tuning.
The SOTs were a big improvement in addition to being battery operated.
They have discrete filtering for each note so that one was not confused
with the machine-made true partials which were often added to the
inharmonic partials which were real. The first version suggested a smooth
12 step graduation within each octave. Later the Stretch Calculator came
on board, and one could interpolate to accuracies of .1 cent (if one could
tune that accurately).
The TI59 programable calculator had a program for computing the complete
tuning for a piano by sampling the stretch of Six C's on the piano. This
enabled one to have a good standard stretch for the entire piano as well
as being able to control the individual octaves. Many of the original Master
tunings were based on this type of tuning with some very slight aural
tweaking. This made sure that all of the octaves sounded good when you played
the C's. However, the computer did not know what was going on in the octaves
of the other notes of the scale. Again, this wasn't too bad, because with
just a little bit of aural adjustment those things could be taken care of.
The first SAT came out with automatic Stretch calculations done internally.
This machine was digital and conformed to the laws of the Medes and Persians
which changeth not, no longer depending upon resistor/capacitor circuitry
to maintain the note to note accuracy. The circular LEDs which were
introduced by the SOT were still incorporated. The advantage (in my view) of
displaying in beat mode rather than in cents mode made relating to what one
hears and sees a bit better. The singular F4 Stretch mode was still used.
(It is amazing how well that still does for the center of the piano). One of
the very nice things about the F4 Stretch facility is that the F4, being in
the vicinity of the center of the soundboard, was usually very
representative of the general scaling of a particular piano.
The Yamaha Piano Tuning machines came out fairly early and included a
display which was quite easy to learn to read. The PT3 and PT4 were
basically the same and allowed one to build a scale much like the Strobe
Tuners did. The later PT100's were designed basically for the Yamaha dealers
so that their pianos would be tuned to a basic factory determined curve.
There were tuning curves for 9 or 10 Yamaha pianos. One could tune other
pianos when comparing piano size with some of these pianos which were
included in the list. There was also one curve which one could build to
suit, but it did not stay in memory. This was one of the easiest systems
to learn. The accuracy was good. The adapatibility for other pianos was
less an advantage. It was not their purpose to compete with other tuning
devices, but to provide better service for their own dealers.
The newer SAT and SAT II added the genius of the three note sampling.
With the great success of the F4 one note sampling, it was found by Dr.
Sanderson, that one could pretty well predict how the Bass and the High
treble should be tuned so that they would both relate well to the critical
center part of the piano. The A4 sample of inharmonicity was a slight
improvement over the F4 in that it was even closer to the center of the
soundboard and that the most important note on the piano was being
directly measured ("Let me hear your A" is heard often among
instrumentalists). The F3 Stretch Number controls the flatness or sharpness
of the Bass tuning curve. The C6 Stretch Number controls the general curve
of the high treble principally. Articles in the PTG Journal about a year ago
explain how one can vary these 3 stretch numbers to achieve an unlimited
variety of tuning curves. Keep in mind that the chief aim to is have both
ends of the piano relate well to the critical center area.
With the advent of the RCT, again Six (or Five) notes are sampled in order
to control how the various octaves relate to each other. There are 10
basic tuning curves available to readily select, plus a customized curve
which the tuner controls completely. The biggest job of the Beta testers
was to help come to some unanimity as to the best "middle of the road" type
of tuning which was assigned to the #4 OTS. From there, one could
stretch to his hearts content. A newer version of the program has added
real slick graphics so that one can see what is going on in all of the basic
octave matching relationships of the A's on the piano. This still does
not in reality deal with the note to note relationships between the A's.
This must be done aurally or by other means yet to be developed, but is
really not a big problem.
The TuneLab programs starts out utilizing the graphic capability and has the
advantage of smooth curving from anywhere to anywhere. It runs on Window95
and is the newest technology out until the SAT III is available from
production runs. The TL has another unique feature and that is that it has
two modes of display which are advantageous in different parts of the scale.
It has unlimited memory for prefigured tuning scales which can be imported,
but does not utilize either of the previously patented procedures for
developing tuning scales. The Graphic method however is relatively fast and
is always fitted to the particular piano because of the sampling method. One
advantage is that one can use as many samples or as few as desired. The main
display mode is quite similar to the Yamaha Tuner display. The other mode
gives a harmonic analysis of each note, so that one can zero in a particular
partial peak to match a predetermined curve. I would write more about this
if I could get my MAC to run Windows95. I think it will happen soon. Take a
rain check.
The Ultimate in Tuning Scale calculation is the Steve Fairchild "Aural
Tuning Emulator". This is all done on a Spreadsheet program which runs in
Super Calc. It is the only program which analyses every note on the piano.
The downside is that one must physically measure the various parameters of
each string (takes about a half hour). This is for very critical pianos
which one tunes frequently. This program fits every note of the piano into
exactly the right place. There is provision for varying the stretch
according to your own preferences. Graphics are available to guide in some
of the determinations. Re-running the program can tweak it just like you
like it. The programm goes through several iterations each time you run it
until every note is within a certain prescribe degree of accuracy. this
is the only program which takes care of the other 11 notes of each octave.
It doesn't care where the scale breaks are located, it still will make the
best compromise where necessary.
Partly because I am a SAT dealer, but mostly because I have used most every
device which has appeared on this planet (including Korgs, early MRH's,
Seike and others), I still prefer the SAT, and especially the new SAT III.
This machine has unlimited Stretch capabilities, and it can be adjusted on
the run. It utilizes tuning by the same partials as the previous SATs. It
has the same familiar display. The automatic note stepping is a real plus.
The ease of using other types of temperaments and many other special
features make this one still my choice.
Finally, just a note about tuning curves. Being an aural tuner of some
note, I have at times been tempted to depart from the smooth curve which
my machine provides. However, when one does alter a particular note,
especially in the critical center section, this will cause other notes to
be altered a similar amount which when considered in their other repective
contexts will not fit so well. I have found that in most cases, it it best
to go with the smooth curve in the middle of the pianos. I no longer try
to tweak a temperament to fit my own personal whim (in most cases where I
think I might improve a certain beat speed, I find that if I more carefully
tweak it to fit the curve, I am satisfied with it in its general context).
Of course, when there are drastic scale breaks in the middle of the piano,
"you just can't tune those pianos", but you can follow certain principles
to improve the local smoothness of at least one set of intervals (your
choice).
Jim Coleman, Sr
This PTG archive page provided courtesy of Moy Piano Service, LLC