Ray Fairfield Wrote in MMD 04.04.09

> This works fine, but was not what I was looking for.
> I wanted quieter soft passages, but changing the springs
> will not give you that. What I got was a piano that only
> gives half of what it's supposed to give.
> I put the original springs back.

I know what you are talking about.  I tried the same thing and the
piano sounded terrible.

What I found to work is to change the way I set the 0 intensity level.
Ignore the vacuum levels for this first adjustment.  Put a roll in the
player and set the tempo to 0.  If the roll still moves, disconnect the
chain.  Go under the piano and look at the position of the accompaniment
regulator.  Now turn the pump motor on and off and see how much the
accompaniment regulator moves.  If it moves 1/2 inch, it is moving way
too much.  Take the zero adjust screw and set it so the difference is
between 1/8 and 1/4 inch movement.  The smaller this movement is, the
better your low level playing will be.  Now take your vacuum gauge and
adjust the spring until you get your 5" vacuum level.

Be careful to not over stretch the springs.  Remember the pneumatic
will move 2 inches more during loud playing.

In my case, it took a few times to get a good balance between distance
moved and the proper 5" level.  Each time I made a change, I would run
the play-no play test on the Duo-Art test roll.  What I found was that
these tests seemed to start working better.  It took a few times before
I got it right.  I also suspect that this adjustment will be different
from piano to piano.  It all depends on how leaky the valves in the
stack.

This is my theory as to why it worked.  The "play-no play" tests starts
with a cord (which should play) and then adds 1 or 2 more notes to the
cord which "shouldn't play".  When I look at the Duo-Art regulator
during these tests, the regulator pneumatic will drop during these
tests.

When the playing notes are played, the regulator drops down just to the
point that it is still regulating properly.  When the "no-play" cord is
played, the regulator drops down to a point that the cloth is tight and
can't regulate below this level and the output from the regulator drops
off very quickly.  The output of the regulator is being purposely
starved because the no-play cord notes being played is leaking so much
that the regulator knife can't open up any more to keep regulating
properly.  This is what keeps the notes from playing.

If we go back and adjust the regulator like it was when we first
started so the cloth would never go tight, the regulator would be doing
its job even during the "no-play" part of the Duo-Art test (which is
not wanted).

Do the same thing to the Solo (Theme) side and see how it sounds now.
The piano should now play more softly on the soft passages.

Pete Knobloch (Tempe, Arizona, USA)