[ Ref. 200324 MMD, Coinola "O" Roll Scale Details ]

I am a self-proclaimed Coinola "O" roll enthusiast.  I have had over
a dozen Coinola "O" roll machines of different models and years.

The MMD O-roll scale can be a bit confusing.  If you are using an
original Coinola "O" roll tracker bar then there are 90 holes in the
tracker bar.  If it was made by player piano company then it could
have 92 holes in the bar.  I will give you the tracker scale for the
original 90-hole bar.

The first hole exposed in the "O" roll is the play hole [hole "A"]
and would be the first hole in the tracker bar on the left side.  It
is larger than the next 88 holes which are the same as many regular
non-transposing tracker bars used in home style player pianos.

The first hole in the scale for these smaller holes is

 1. tympani,
 2. bass drum and cymbal,
 3. tympani,
 4. wood block,
 5. snare drum single tap,
 6. snare drum roll,
 7. triangle,
 8. sustain pedal,
 9. hammer rest rail soft position,
10. hammer rest rail loud position (down),
11. mandolin off,
12. mandolin on,
13. flute pipes on,
14. xylophone or bells on,
15. soft drums,
16. regular vacuum to snare drum (see below),
17. bells or xylophone off,
18. motor shutoff,
19. flute on,
20. to 31. notes E to D#, octave coupled to lower bass notes,
32. to 85. notes E to A,
86. tambourine,
87. pump amplifier in CO and SO models,
88. crash cymbal in SO model.

The last hole [hole "B"] is a larger hole for rewind.

In early Coinola X models the wood block beater is single stroke and
in later models it is a repeating beater.  Early Coinola X models have
a small pneumatic that moves the tympani beaters closer to the head of
the bass drum producing a soft effect.  The snare drum has a little
device that limits vacuum for its soft effect.  Some scales show the
pipes coming on also opening a set of swell shutters.

Holes 15 and 16 have been reported to also provide low vacuum to the
piano but I have not found that device in any original Coinola pianos.
The scale can be found in the book, "Rebuilding the Player Piano," by
Art Reblitz.

The O-roll has the capability of being one of the most musical rolls
made by American manufacturers.  The drums play softer in an original
machine than I have seen in many homemade machines.  The piano can play
a nice accompaniment to the solo instrument.  As in a good band the
solo instrument is not really much louder than the piano.  There is
a muffler rail in many of these machines that silences the top twenty
four notes when the solo instrument is playing.

This scale has the advantage of having more notes that it can play in
the piano section than some other roll formats.  This allows the piano
to play a nice accompaniment to the solo instrument.

Don Teach
Shreveport, Louisiana

 [ Dave Burritt wrote in 200324 MMD, "I am converting a nickelodeon
 [ that uses the Play-Rite "O" rolls."  His instrument might be
 [ equipped with a genuine 90-hole Coinola tracker bar, or a 92-hole
 [ Player Piano Company (PPCo) tracker bar, or even a 98-hole tracker
 [ bar salvaged from a Welte-Mignon Licensee spool frame.  The scale
 [ at https://www.mmdigest.com/Gallery/Tech/Scales/Coinola-O.html 
 [ uses the numbering system of the 100-hole perforator at Play-Rite
 [ Music Rolls and other firms, and therefore is independent of the
 [ tracker bar that plays the roll.  -- Robbie