The question was in regard to the Theme being set to one "degree" above
the Accompaniment.  Jim Heyworth's answer was correct, but I would like
to add this.  For example, the zero intensities of both Theme and
Accompaniment are different.  The Theme setting is between 1/4"- 1/2"
vac. above the Accom. setting.  The reason for this is so that the
Theme can always override or take precedence *over the same intensity
setting* on the Accom. side.  It's spring is larger, anyway, and its
slope is greater, so it builds up faster.  A degree just means "some."
Actually, it is the loudness that is just the next step up the decibel
scale that you are able to detect, i.e. 3db.

If the score calls for a #10 Accom and a #10 Theme, then as soon as the
snakebite hole appears, that Theme will override the Accom. loudness.
But if the Theme called for is a #10, and tries to play over a slightly
louder accompaniment setting the one-way theme flap valves in the box
will not open because the Accompaniment is still greater than the
desired accent, and keeps them snapped shut.  They protect that side of
the stack from receiving a softer accent than what they are already
playing.  (Which is what Jim Heyworth also said).  To suddenly drop the
pressure with a Theme intensity requires that you drop out the
accompaniment first, which in turn would depressurize the entire stack,
not just treble or bass.  (The Accompaniment perfs are the 4 holes on
the left end of the trackerbar.) This is why Theme accents are always
louder, and never softer than accompaniment played at the same time.

A full Duo-Art is sort-of like a Recordo with accents.  Like Jim said,
it plays mainly on the accompaniment settings, and then accents certain
notes and passages by precision snakebite holes which allow a few
milliseconds' time to set up the expression before playing it.

So Accompaniment changes require more time to express than Theme
changes because of the time required by its accordions to get adjusted.
Accompaniment is limited by the speed with which the accordions can
move.  However, Duo-Arts also play notes between Accompaniment changes,
which must mean that Aeolian timed their speed and knew about how much
power they could expect at a certain degree of collapse or relaxation.
This also might explain why certain unrelated codes were used in
transitions that didn't seem to affect the notes.

Craig B.