In answer Joe Orens' question:  The reason that theme holes in Aeolian
products are small is, I believe, more an accident of history more than
a reason of design.  To understand the reasons, you must consider the
design history of the Themodist system and Aeolian's design approach of
what we would now call 'backwards compatibility'.  This expands on my
post in MMD 1997.08.28.09.

Aeolian introduced Themodist publically in the UK in November 1907, in
65-note instruments; they hadn't started to make 88-note instruments at
that time.  The theme holes were added at the ends of the 65-note scale,
spaced on the same 6-to-the-inch pattern as all the other holes.  A
themed 65-note tracker bar looks exactly like a normal 65-note tracker
bar, simply with 67 holes instead.  All the holes are the same size.

Now, consider the size of perforation used for 65-note rolls.  If a
theme perforation was of the same size, it would open the tracker bar
port for a considerable time, and would not be specific enough to pick
out an individual row of perforations to accent them.  So, if one
perforation spanning the tracker bar port would be too large, the
logical thing to do is to use two small holes next to each other.
They let in the same amount of air to operate the valve effectively,
but are open for much less time and so accent more precisely.  I would
be very surprised if there was anything more than this behind the
choice of small theme perforations!

When Aeolian adopted the new 88-note roll standard (in 1909), they
clearly decided to keep the same configuration for the theme holes,
even though they were really related to the 65-note scale.  (Why they
did this I don't know.  Patent reasons, perhaps?)  The paired small
perforations were kept.

Likewise, a few years later (pre-1914) when the Duo-Art was designed as
an enhancement of the Themodist system, these 65-note scale theme ports
were kept.

Other makers of themed 88-note rolls didn't all use small theme holes;
many of the European makers (such as Hupfeld), used ordinary note-
sized perforations for theming, although they were almost always paired
into 'snakebites'.

Duo-Art roll editors were inventive types, and found they could make
use of this inherited design feature.  Because the theme system has
a finite 'rise time', full theme suction levels are not reached within
the duration of a single-row theme perforation.

It is possible to exploit this by using two or more rows of theme
perforations for most accents, but only a single row of theme
perforations before lesser accents.  It allows more shading in the
dynamics, three levels from an apparently two-level system.  This
potential subtlety was exploited to a limited extent, although most
rolls seem to use two rows of theme perforations as standard.

The other use of single row accenting is to make the accent more
precise in very complex music where it is undesirable to allow
subsequent notes to pick up the residue of the accent.

Many post-event rationalisations of the Duo-Art system have assumed
the small theme perforations to be a clever design feature.  I believe
the existence of these perforations in the 65-note system many years
before very clearly disproves this !

And for modern recuts?  Most Duo-Art accents use two rows of theme
perforations, which are pretty well the same length as a single ordinary
perforation.  For these, it is completely accurate musically to use a
single row of ordinary perforations in a recut roll.

 [ This is an important concept: a single hole of ordinary size in
 [ a modern recut is the same height as the double-punched theme
 [ hole in the typical old Duo-Art roll, and therefore works the
 [ same.  -- Robbie

Complex pieces, or rolls which have been coded with double/single-row
accenting, may be compromised by using larger perforations.  The really
important thing during recutting is to make sure the relative position
of theme and note perforations is maintained; errors which separate
theme from note will be very damaging musically, irrespective of the
theme perforation size.

Listen to recent 'Custom Music Roll' recuts: these use ordinary note
perforations for accenting, but are very accurate in the positioning
of them.  Most Duo-Art pedants I know regard these as perfectly
acceptable!  Older mechanically-read recut rolls, even those with small
snakebites, are prone to reading errors so are often not as good.

Of course, the 'holy grail' of Duo-Art recuts should be with us in the
near future: using computerised scanning to recreate the exact original
perforation pattern with all its interrelationships intact, and cutters
of the right scale.  Fingers crossed, all the components are in
place...

Julian Dyer