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MMD > Archives > February 1999 > 1999.02.17 > 09Prev  Next

Rolls For Regulating Reproducing Pianos
By Craig Brougher

I would second the motion that the only way to regulate a reproducer
properly is to final-regulate by playing many, many rolls through it.
In one sentence Bob Taylor explained the real secret to restoring
reproducing pianos.

Regulating reproducing pianos well is the most difficult job in all
playerdom!  And what's so difficult at times is the fact that in a few
of them, after you have done everything -- you think -- perfectly, and
you are proud of the instrument you've finished, you begin to hear a
flaw that can only be fixed by dismantling it, tearing down the stack,
and finding the problem.

Aeolian test rolls sold and distributed to the sales force and to piano
houses, I suspect, were considerably abbreviated versions of the ones
the factory used, however.  There was never a reproducer more needful
of a good test roll than the Duo-Art, and more lacking of one.  But
after you have roughed in the expression with their tests, you should
"note-for-note" the action at zero intensity, to begin with.

To do this you can use any 88-note test roll with a full arpeggio
scale.  Without any expressions playing, you are set to the zero
intensity when the Duo-Art is on.  Pull the sustain pedal tube (3B) and
very slowly play the roll, adjusting to the finest degree of striking
possible.  All the notes should play equally at the lowest intensity
able to play the piano.  At least, that is the ideal.

At first, you will probably have about half the notes to play
satisfactorily, and the other half will either be too loud or missing,
or whatever the problem.  From there is where you start to regulate!
Once you get it right, play the same arpeggio without the sustain pedal
on.  That should cut the number of notes playing by about 1/3 to 1/2.
When that check is made, the zero intensity is going to be about right.

Duo-Arts whose valves are set too closely will never meet this pppp
requirement, and will not play well on ffff, either.  Valves set too
far open cause the instrument to lose air during expression transi-
tions.  You can tell this by the fact that it plays the test roll
perfectly, but still needs to be hiked up to play "performance" rolls.

What's happening is, when the roll takes the piano to a soft transi-
tion, or through a number of soft transitions -- especially back and
forth through the zero level or close to it -- the travel losses of
"gappy" valves cause the stack to drop out.  And, it doesn't take much,
either.  That is why the Duo-Art really needs a much better test roll.

If you want to know which performance roll I use to check out this
effect, it is called "Negro Heaven," by Cessana.  Of course, that roll
or no roll tests all the notes on the piano for the same effect.
Therein lies the basic problem.

As far as test rolls go, the Ampico B test roll is the best ever
devised.  It is a real test roll, and tests every note.  If your B will
play that test roll, any further adjustments should be very minor ones,
if any at all.  I've always felt that most reproducing test rolls were
provided mainly to prove to someone that their piano was really working
just fine.

Craig Brougher

 [ When I worked at Lockheed I wrote two different test procedures
 [ for my products: an Acceptance Test Procedure (ATP) and a
 [ Functional Test Procedure (FTP).  The ATP was only performed once
 [ but it was grueling: it had to convince the suspicious customer that
 [ _everything_ worked per his specifications.  The FTP was a much
 [ simpler demonstration that the device still worked okay after
 [ repair.  Sometimes the shop asked me to write a Test and Alignment
 [ Procedure, especially when several adjustments would interact
 [ and cause frustration.

 [ New piano designs probably never had an ATP; "Shoot the engineer and
 [ get it to the dealers!"  The FTP is the simple test roll, which
 [ helps to show that the technician has replaced the hoses correctly.
 [ The conscientious player tech needs a well-designed test roll and
 [ well-written procedure to regulate the reproducing piano; without
 [ these test materials he can only learn by years of experience, and
 [ by using a big box of his personal 'test rolls'.  A truly fine
 [ performance by a reproducing piano still relies on the art and skill
 [ of the technician who adjusts and regulates everything.  -- Robbie

(Message sent Wed 17 Feb 1999, 13:41:38 GMT, from time zone GMT-0600.)

Key Words in Subject:  Pianos, Regulating, Reproducing, Rolls

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