Pitch Raising (was Otto Higel)

[Dean L. Reyburn, RPT]

Ty Fairchild writes: ( I think it was Ty)
>:> This technique [tuning just the center string, then one edge, then
>:the other edge]  results in less strain on the plate as the tension is
>:> distributed more evenly and gradually, which is surely a comfort when
>:> pulling up old pianos. It also results in far fewer strings breaking,
>:> and perhaps more importantly, ends up with a vastly more stable
>:> instrument.
>:
Allen Leigh writes:
>:Ty, I can understand why that technique reduces the strain on the
>:plate because, as you said, the stress is distributed more evenly,
>:and I can understand that this would give a more stable tuning.  I
>:don't understand why this would result in less string breakage.  If
>:you could elaborate on this, I would be grateful.
>
Ty Fairchild writes:
>Ummm.  I was hoping no one would ask. ;-) It is a cold stone fact that
>using this method results in less string breakage, but I have no clue
>as to why. Sorry. But if any one else knows, I, too, am all ears.  :-)
>
I have been doing research for some time on pitch raising with the
Accu-Tuner, and have to disagree strongly with Ty Fairchild.  My study
shows that the best method is simply to start at the lowest note on the
piano, and move up the piano chromatically, pulling the unisons up as you
go.

Dr. Sanderson did some extensive research a number of years ago that
showed this to be true.  Pulling up the unisons as you go will actually
result in a _lower_ maximum overpull!  This of course lowers the chances
of string breakage.  My own experience of thousands of pitch raises here
in Michigan bears that out.  I switched to this method (chromatically
pulling up unisons) in 1990, and the number of broken strings went way
down after the switch.

My experience, and that of many other RPT's indicates that raising the
center strings first, and then the left and right strings later results
in *LESS* tuning stability than if you just pulled up the unisons as you
go.  I have not researched the stability aspect with hard data though.

As to plate stress, plates break because of flaws in the casting.  If you
have ever been to a piano factory, they pull the full tension up as they
string the piano!  Think about that, there is absolutely no tension on
the unstrung part, but the part that was just strung is pulled to full
tension.  If a plate is going to break, that is when it will happen if
this puts undo stress on the plate, *not* when you or I pitch raise the
piano.

It was hard to re-train myself to tune unisons-as-you-go since I had
tuned and pitch-raised aurally for so many years before.  The Sanderson
Accu-Tuner is simply the best system there is for pitch raising, bar
none.  It is a stable target, while the piano moves around on you.  Pitch
raising aurally simply can't compete, since your ear is not absolute like
the SAT.

Dean

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Dean L. Reyburn, RPT                    Sanderson Accu-Tuner
 REYBURN PIANO SERVICE, INC.             Authorized Distributor
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