I see that Robbie published the description which I sent him last summer,
of the Wurlitzer system of tempo-compensation which was engineered into
their production perforators (by inventor Ernest Clark, if I recall what
Don Rand has told me accurately).  My description to Robbie was
accompanied by photographs of the mechanism; without them, my feeble
description is probably about as clear as a stone window.  But the reason
for the description in the first place was to disprove contentions that
Wurlitzer band organ rolls were not as sophisticated as they, in fact,
are.  Tempo compensation is built into each roll in a smooth curve of
imperceptible incremental advances, paralleling the increase in paper
speed as a playing roll travels across the tracker bar.

Robbie's preliminary notes to my description are on the money.  The
masters were cut in measures of uniform length, from the start of the
master to the end.  It took ten masters, one for each tune, to make a
ten-tune roll.  All masters, whether for style 125, 150, or 165 rolls,
were cut on the same master cardboard.  A master generally formed a
cylinder about 10" in diameter, creating such a storage problem over the
years (considering the variety and quantity of mechanical music produced
by Wurlitzer) that they usually destroyed their masters after the
popularity of the tune on a given master had waned.

Wurlitzer production perforators (and they had at least 12, of which 3
survive) read the masters mechanically -- not pneumatically -- by indexing
rods.  They were amazingly quiet, yet still fast.  Anyone who has heard
the racket made by an Acme perforator, or QRS's or Play-Rite's (and I
have seen them all), will marvel at the operation of the Wurlitzer
perforators.  Ernest Clark was a genius!

In the "Tempo Compensation" article Robbie mentioned the factor which
influences the need for tempo compensation being built into a roll or not:
if your roll is short and your take-up spool diameter is huge, you can get
away without tempo-compensating the music.  If your roll is long and your
take-up spool diameter is relatively small, you will need to compensate.

 [ Editor's Note:
 [
 [ The "indexing rods" Matthew mentions may be similar to the feeler pins
 [ of the punched-paper-tape readers developed by Teletype(T) Corporation.
 [
 [ You say 3 Wurlitzer perforators survive today, Matthew.  Can they be
 [ viewed?  Do drawings of the mechanisms exist?  Are any old perforators
 [ from other music roll companies on display?  Their mechanisms could
 [ tell us a lot about the "steps-per-foot".
 [
 [ -- Robbie