[ Don teach wrote:

> The great Style "O' roll already has holes in the roll to turn on and
> off a set of pipes and a set of bells or xylophone -- no multiplexing
> is required.  ... There are also holes in the roll to operate drums
> and other percussion devices, as well several expression holes to
> control the vacuum levels for the piano and drums.

In addition, when you look at "O" rolls you can easily see if the holes
in the "solo" section are perforated for percussion instruments such as
xylophone rather than for pipes.  The holes for percussion are short
holes and produce a rather unsatisfactory sound when played on pipes.

There are perforations there to control both types of instrument so you
should make your choice appropriately when it comes to adding solo
instruments to an "O" roll player.

Hal Davis
Leslie, Michigan