I'm in the process of converting my Aeolian player to Duo-Art, and
I have just finished restoring the expression box, with one minor
modification.  I have not included a device, which seems to be an
original part, which prevents the accordions from closing fully thus
softening the play.

Since the expression box was brutally "restored" by destroying internal
channels to get direct connections between the exhaust nipple and the
bass and treble nipple some time when the expression stopped working,
I suspect some cafe owner to have seen the opportunity to earn some
more nickels out of the piano before it finally was discarded.

However, I don't feel sorry to not include this device in my restora-
tion, since the box mostly seemed to be produced without it, and it
partly ruins the expression of the music.  I would not like to just
throw it away since it is an original part and would like to trade it.

Maybe there is some owner of a Duo-Art in a public place like a hotel
or a cafe out there who has to "protect" their customers against
unexpected realness (loudness!) of the volume of the entertainment
music.  By the way, player piano enthusiasts love the music at the
loudness it was composed for.  The player piano was not invented for
Muzak or elevator music purposes... :-)

A picture of the device when my box was unrestored can be found at
the Pictures page of the MMD web site:

    http://mmd.foxtail.com/Pictures/johnsonrod.jpg

For those who might not be able to view the picture, it is a rod going
under the two large pneumatics under the expression box.  It is screwed
on, on each side of the box, near the rods to the accordion pneumatic,
and consists of a movable and two (one on each side, where it is
screwed to the box) not movable parts.

The movable part has two "ears" one on the theme side, and one on the
accompaniment side, which, when the device is in the "soft" position,
obstructs the rods connected to the accordion pneumatics, so they will
not travel all the distance down on FFF.  This, of course flattens
music needing that level of expression.

There is also a sign in the same material as the Duo-Art and pedal
on/off switch signs, with "SOFT" and "NORMAL".  A picture showing how
this originally was mounted is also included.

Some minor modifications must be done by adding felt where the rods
meets the "ears" of the device.  It can be turned on and off, so that
the Duo-Art can be played normally on concerts.  I cannot guarantee
that this was one of the most clever inventions from Aeolian, so feel
free to discuss or comment this device critically, if someone else has
experience with this device.  I do not want to cheat someone, nor
throw away a seemingly original part.

Sincerely

Thomas Henden