I know that most readers are not as involved in the Aeolian organ as
I am, but I need to publish this anyway.

Many Aeolian Duo-Art organs had an "Echo" organ that was some distance
away from the main organ.  The Duo-Art rolls used this attribute to add
dimension to the music.  Typically, the Echo organ had a minimum of
three stops, but often there were many more.  When the roll called for
the Echo to be engaged, it was coupled to the upper holes of the
tracker bar, which is the Swell division.

The test roll labeled this Echo test as "Echo Only", which means that
when it is engaged, the Swell division is to be silent and the Echo
(only) plays these holes.  This Echo coupler hole is the first hole on
the left of the upper row of tracker holes and is the #2 tracker hole.

Of course many Aeolian organs had no Echo division, and those organs
were wired so that nothing changed when that hole opened.  That hole
was simply ignored.  The roll continued to utilize the Swell division
playing the holes on the upper row.  In those passages I have
observed that there are a variety of stop settings and sometimes stop
changes in the portion of the roll where the Echo is supposed to be
playing.  That suggests that the Echo, when used, should be capable
of changing stops.

On the early Duo-Art rolls, there are printed instructions telling
which stops are being set automatically.  This gives the user the
option to turn off the automatic function, and manually set the stops
using the printed instructions as a guide.  One can either follow those
instructions, or make a departure from them, to add personal flavor to
the interpretation.  This is much the same as a Duo-Art piano roll with
its dynamic line.  Thus the "Duo" in the name, either preprogrammed
automatic, or personal interpretation.

But the organ roll instructions for the Echo are always the same.  At
the beginning of the roll, if the Echo is used anywhere within that
roll, are the words, "Prepare Echo... String pp, Vox Humana, Flute p,
Tremolo".  This means turn on those stops at the beginning, and at the
giving point later in roll, turn on the Echo coupler and those stops
then start to speak.  The Echo coupler switch on the console also
releases the Swell division, leaving the Echo division, only, to play
the notes on the upper holes.  But what about the rolls where stops are
changed during the Echo passages?

Faced with trying to solve this apparent inconsistency, I set about
wiring my organ to set the Echo stops to parallel with the stops on the
Swell.  Thus, if the Vox Humana is drawn on the Swell, it will be drawn
on the Echo too if the Echo coupler is engaged.  I followed the scheme
of matching my four Echo ranks to like ranks in the Swell.

At this point I should add that the Duo-Art system sets 27 stops
divided in this manner: 4 stops in the Pedal, 13 in the Swell, and 10
in the Great.  There is no direct way to control the Echo stops.  My
scheme enables the Echo stops to tag along with the Swell stops.

Once the wiring was complete, I started listening to the rolls in which
the Echo was used.  I was pleased with the results until on one roll,
there was absolute silence during the passage where the Echo was
engaged.  Obviously, there was an error in my scheme.  Still in the
experimenting phase, I changed the wiring so that the Echo String pp
was always on when the Echo was engaged.  That solved the problem of
the silent passage, and it sounded good.

Up until this point, I have been talking about coupling the Echo to the
Swell.  All literature and the test roll identify upper tracker hole #2
as "Echo Only".  Duo-Art rolls change the stops by flipping toggles in
a device called a jackbox.  The corresponding jackbox junction wiring
posts for hole #2 position are very different in that there are eight
wiring positions.  Most others only have two or four wiring positions.

Some literature indicates that tracker hole #171 is the Echo coupler to
the Great.  The test rolls I have seen (4) only give it a number, 171,
and nothing else.  But this position on the jackbox also has eight
wiring positions, just like the #2 position.  No other jackbox position
has eight wiring posts.

When I first wired my organ, I assumed that hole #171 was just like
hole #2, except that the Echo is coupled to the lower holes or Great.
It wasn't long before I realized that the Echo was almost never coupled
to the Great, and when it did, things just didn't sound good.  The
problem was the standard three ranks drawn on the Echo were just too
soft for the passage being played.  Often the Swell ranks would totally
overshadow the Echo.  So I experimented and allowed the Great division
to play _simultaneously_ with the Echo when it was coupled to the
Great.

Voila!  It was wonderful!  When the Echo is now coupled to the Great,
the two divisions play together, and all four stops of the Echo are
drawn.  This is perhaps the first home entertainment surround sound
system.  No doubt, the larger Aeolian installations brought in the
antiphonal sections with hole #171 and rocked the place big time.

What does this mean?  Aeolian didn't tell us everything they were
doing.  And, it appears, that sometimes they changed their minds.
The 176 holes in the Duo-Art organ rolls were not fully utilized; some
are still a mystery.  My philosophy is that when we want to solve these
mysteries, we need to study the rolls.  I have been doing that with
Ampico and Duo-Art piano rolls for over thirty-five years, and for ten
years, the Duo-Art organ rolls.  The rolls are the 'Rosetta Stones'.

For you organ buffs, what does the Aeolian LCW mean?  That will be
reveled in an AMICA Bulletin article in the future.  I think I have
figured it out.  It's a new theory.

Bob Taylor
Columbia, Missouri