I would like to describe the Duo-Art transposers that I have seen.
They are different from the ones [in Australia] that Paul Brennan
described yesterday.  On my transposers, notes 1-4 and 85-88 can
never be played because there are no pneumatics for them.  There are
also no holes in the tracker bar for them -- the group of four holes
is drilled or routed out to make a large space where the four holes
used to be.

The transposing section of the tracker bar consists of a group of
just 80 holes that can slide to the treble or bass edge.  All the other
holes in the tracker bar remain stationary at all times.

Here is where the tricky part comes in.  If you move the transposer
one, two, three or four positions towards the bass, then the entire
group of notes #5, #6, #7 and #8 are now turned off because they have
been moved to where the notes will play the Accompaniment coding.
Whether you move the transposer one position or four positions, the
group of notes 5, 6, 7, and 8 is always cutoff.  The music plays keys
one, two, three or four positions higher in pitch.

However, if the tracker bar is transposed one, two, three or four
positions notes towards the treble, then the entire group of notes
#81, #82, #83, and #84, are automatically turned off so that they do
not read the Theme coding.  The music now plays one, two, three or
four notes lower in pitch than before.

Aeolian used the same square cutoff blocks with only 8 nipples
instead of the usual 16.  However, these cutoff blocks have nothing
to do with notes 1-4 or notes 85-88 since they can never be played by
a roll.  The cutoff blocks control the group of notes 5, 6, 7, and 8
in the bass and the group of 81, 82, 83, and 84 in the treble.  Aeolian
used little pallet valves similar to the tracking ears to tell which
cut-off block to activate.

I hope that clears things up; if not please ask questions.

Randolph Herr