[ Ref. Cecil Dover in 21.07.08 MMD

Cecil, Greetings from north of The Bronx! In regards to your inquiry
about an 'O' roll Tracker Bar Description, I am attaching a link to an
MMD article that was contributed by Don Teach back in November of 2001.
In it you will find a listing of the 'O' roll Tracker Bar as though you
were looking at the tracker bar from the front, listing the functions
from left to right.

The first hole is an enlarged control port, in the same position as
would be the Sustain Pedal on a standard 88-note tracker bar. This is
the control for the 'Play' function, which is activated after the roll
has rewound. Generally, three long slots in the roll will cancel the
Rewind function and shift the roll frame into the Play mode.

In some 'O' roll scale descriptions this hole will be identified as
hole 'A', while on the opposite end of the tracker bar the large hole
to the right of hole number 88 will be designated as hole 'B'; this is
the Rewind function,

After hole 'A' (on the left), the first small tracker bar hole is
number one, the first of two tympani beaters. The rest of the holes are
pretty straight forward from 2 through 19, these being percussion and
control holes.

Holes 20 through 85 are the playing notes (65 consecutive playing
notes.) The last three holes are for tambourine, Amplifier, and crash
cymbal, in that order.

Be aware, though, that Player Piano Company offered 'O' roll scaled
tracker bars that had an additional two tracker bar holes, one on either
end of the standard 88-note holes. Thus the holes would or could be
listed as 0-89, besides the larger control holes on either end of the
tracker bar. (The extra-holes were for an anticipated up-scaling of the
regular 'O' roll scale, possibly for an additional solo instrument or
multiplexing of existing instruments and/or functions.)

So, be sure to count the smaller tracker bars holes to see whether or
not you have these extra holes. And if you do have the additional two
holes, be sure to skip the first, or in that case #0 hole, and tube up
the tracker bar in the listed order (#1-#88). This is to make sure that
the 'A' and 'B' holes are properly aligned.

In piano based instruments, the bottom octave on the tracker bar scale is
teed or 'Y-d' to the next lower piano octave. This gives the instrument
a more fuller piano bass. The Solo instruments play at least one octave
lower than the piano scale that they 'shadow'.

The following is the link to the article by Don Teach:

https://www.mmdigest.com/Archives/Digests/200111/2001.11.24.html 

Attached also is an 'O' roll schematic that was drawn by the late
Adam Lojewski. I hope that this is of some help to you,

Dale F. Rowe
Bronx, New York
FredsOrchestrion@aol.com

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