Yamaha digital tuning scope

Allen Leigh allen@pengar.com
Sun, 03 Dec 1995 20:04:40 -0700


>Do any of the techs here use the Yamaha PT-100 tuner?  I haven't used a fork
>for over 10 years, except to aurally demostrate to the customer just how
>flat their piano is.  I've  used the Hale sight-o-tuner with good results.
>I  use the Hale tuner to find the pitch of the piano,  find the pitch of the
>organ in a church if the piano must be tuned to it,  tune the piano to
>standard pitch, or sometimes to check temperment on weird scaled pianos.

>The Yamaha tuner has intrigued me for some time.  Any comments on it would
>be welcomed.

>Daryl Matthies
>MATHIS PIANO SERVICE

Hi Daryl,

I use a PT100 and really like it.  It is accurate to 0.2 cent and
covers the entire piano.

It has builtin scales for the Yamaha M1, U1, U3, C3, C5 and CF.  In
addition it has a flat scale and one labeled CP which I think is for
antique temperments.  When doing non-Yamaha pianos, I've found that
those scales widen the temperment a little bit too much, and I have
to decrease it.  I tune F3, the first note in my temperment.  Then I
set the tuner to measure the second partial of F3.  That partial is
frequently 1-2 cents flat relative to the builtin scale, and I
distribute that flatness over the temperment octave by subtracting
0.1 or 0.2 cents from each note in the temperment.  The result is a
temperment octave that begins and ends with the first & second
partials of F3.

Then I use the tuner to tune the piano using 2:1 octaves.  When I'm
tuning below the temperment, I adjust the tuner to have no movement
in the display for the first partial of the higher note (it has
already been tuned).  Then, I tune the lower note
(second partial) to have no movement in the tuning.  This allows me
to tune octaves with 0.2 cent accuracy, which is better than I can
hear octaves.  When I tune above the temperment, I just reverse the
procedure by adjusting the tuner to have zero movement in the display
for the second partial of the lower note (it has already been tuned),
and I tune the first partial of the higher note to have no movement.
This procedure was given by Reblitz in his book.

I use the tuner to tune unisons, getting 0.2 cent accuracy.  I can
hear unisons that are off 0.2-0.4 cents, so using the tuner hasn't
given me greater accuracy in my unisons, but I think it is faster for
me,
especially in old pianos with "jumpy" strings and strings that don't
want to move.  One of the things I like about using the tuner for
unisons, is that the tuner allows me to measure the rate at which the
pitch is rising as I tighten the string.  This helps me avoid broken
strings.  For example, when the pitch of a string is within four or
five cents of where it should be, it should take very little movement
of the hammer to bring it on pitch.  If I need more movement of my
hammer than I should, then I know that all I'm doing is tightening
the small section of string from the tuning pin to the bridge, and
that means that I'll break the string if I keep going.  I can
see in the movement of the display how fast or how slow the pitch is
rising, and that tells me if the string movement is getting past the
bridge.  Of course, tuners can do the same thing with their ears.
What I'm doing is substituting an electronic device for my ears.

Before anyone flames me for using the tuner to tune unisons and
octaves, let me mention that anyone who has studied the theory of
making measurements knows that differential measurements (difference
of two almost equal values) is more accurate than absolute
measurements.  When a tuner tunes by ear, he or she is doing
differential measurements.  When I tune with the PT100, I'm doing
absolute measurements.  Thus, there is great risk that my tunings may
not be as accurate as they would be if I tuned only by ear.  However,
the 0.2 cent accuract of the PT100 is great enough that I can do
absolute tunings and get good results.  That is, I adjust each string
separately via the tuner, and the resulting unison is great.  I
listen to each unison and each octave and satisfy myself that the
tuning is the best I can get.  Once in a while, I have to touch up a
string by ear because the tuner isn't quite on.

My background is as an electronic
engineer and computer programmer, so to me using electronic test
instruments is "normal".  For me, I get the best of both worlds, a
accurate tuner and my ears.  When they both agree, then I'm
happy with that note.

I do alot of school tunings in noisy rooms and hallways, and I like
the PT100 for that because it allows me to tune when I can't hear the
beats.

The SAT is a better tuner than the PT100 but it costs considerable
more.  It has (I think 0.1 cent accuracy).  In addition, it has FAC
tuning (I've forgotten the octaves for those three notes).  From
hearing those three notes, it calculates the "proper" settings for
all 88 keys, thus taking into account the inharmonicity of the
particular piano, as given by those three notes.  This would be great
for noisy rooms.  My method of using the PT100 takes into account the
inharmonicity of F3, and I have to make the assumption that the
inharmonicity is the same for the other notes. However, since I'm
tuning 2:1 octaves, I take into account the inharmonicity of the
second partials in tuning adjacent octaves.

/Allen Leigh

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Amateur Radio Station W7RCP



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