In the 070913 MMD Kim Bunker discussed Ragtime player units.  Here is
my humble opinion.

I've written several rather critical articles on this subject.  There
are both good and bad points to the Ragtime design.  I will address
both.

The system indeed does work.  However, to anyone who has heard a well-
designed system play, the results are mediocre at best.  And I do per-
sonally like the idea of retrofitting a regular piano, turning it into
something that is fun to listen to.

Ken Caulkins' units, while cleverly designed, have plenty of room for
refinements.  He has also tackled the problem of scaling the units to
fit any piano quite nicely.

However, the air chambers in this two- tier system are too small.  On
low suction the units cannot get enough air flow and will often drop
out while playing heavily scored musical passages. If the units and
feed tubing were made larger, designed to be laid out in a three-tier
design, the difference would be dramatic.

The units clamp onto steel rods and must be supported at the breaks, or
the whole affair will bounce, wasting much of the lift of the pneuma-
tics, which barely have enough span to start with.  (I'll address this
in a minute.)  A three-tier system would use larger rods, perhaps
small-diameter water pipe, for support.  It is then quite possible that
this support could be hollow, greatly cleaning up the suction-supply
hoses.

The tracker bar tubing is a nightmare on these, stuffed between the key
breaks, causing most piano servicemen off, often into oncoming traffic!
In operation, the tubing often jams and rubs on the keys.  The tubing
is right in the way where you need the stack supports -- at the breaks.
This presents several problems.  First, it makes the piano action most
difficult to service.  The unit must be pulled from the piano, turning
into a hopeless, tangled mess as you remove it.  If the unit were con-
structed to stand alone on its own sub-frame, with the main supports
resting on top of the key cheeks (rather than relying on the piano case
itself), it would be much easier to remove the upper unit.

I also believe that it would largely eliminate this mess, if the center
keypins were replaced with steel hollow tubing of the same diameter,
extending to below the keybed.  It would then be an easy procedure to
figure out where the tracker bar tubing goes: to the keypin (key) which
it operates.

The action abstracts are presently serrated nails, which will wear a
notch into the foot of the pneumatic very quickly.  These need to be
smooth nails, and covered with pieces of small tubing or heat-shrink.
Or better yet, a sticker with a regulating button.  If the pneumatic
units had a little more span, with a stop-rail installed, the unit
could be then be fine-regulated to the piano.

This will make a vast difference.  The pneumatic will then positively
lift the sticker.  As it is, it does little more than "shoots" the
sticker upward, causing the music to be very choppy.  A good rule of
thumb in any player system is this: if the backchecks operate on soft
playing, the system is working properly.  Relying on the span of the
pneumatics alone for regulation just won't work.  Every piano is
different.

Unless Ken has redesigned it lately, the plastic tracker bar is
useless.  Although it is a marvel of plastic-injection engineering, the
upper and lower row of nipples are far too restrictive, causing the
valves tubed to these rows to be starved and not fully lift.  High
suction overcomes many flaws, but lower suction offers far less motor
noise.  I want to hear music!  If I wanted to hear a vacuum motor run,
I'd plug in my antique Kirby!

This _could_ be a fairly good system with some refinements to both
design and installation.  I have retrofitted several pianos with home-
brew stacks.  I've also made many mistakes.  But the learning experi-
ence has been priceless.  Your completed retrofit will be examined
under a microscope by your rebuilding peers, so just make sure that it
comes as close to original performance as humanly possible.  We should
look back and see what the original designers did and why.  There is
always a reason.

Andy Taylor