Hello.  There has been some talk going around about player pipe organs.
I have two things to contribute.  First, I read a book on the organ
that showed different pipe organ actions and included some drawings
of pipe organ actions.

There were two of note: the vacuum action, and the pressure action.
Because they worked the same as the vacuum and pressure band organ
valves (the only difference being valves at the back ends of the
keyboard opened the tubing) I wondered why someone didn't split the
tubing and insert T's, and hook shorter lengths of tubing from there
to the tracker bar.  Has anyone ever tried this?

Second, I've read in the Encyclopedia of Automatic Musical Instruments
about certain models of Aeolian Orchestrelle using pressure and a roll
box.  I've never heard of a reed organ using pressure!

Hope to hear from you soon,

Andrew Barrett

 [ A vacuum system is convenient for music rolls because the paper
 [ is sucked into contact with the tracker bar.  Some cardboard book
 [ systems operate with pressure, but a grooved roller is usually
 [ needed to keep the music in contact with the tracker bar.  Putting
 [ the tracker bar inside a pressurized box is a solution, but it's
 [ inconvenient...  -- Robbie