I like the elegance of Paul Ward's idea [991228 MMD]; now we need
some more data to predict the performance and operating expense.

For instance, how fast (centimeters per minute) can a 5-watt laser beam
cut a line through 10 sheets of modern wax-coated music roll paper?
Maybe more power is needed; what's the cost of a 50-watt laser cutter,
and its cutting rate, and the expected life, and maintenance costs?

How many little round holes (2.0 mm) can a 5-watt (or 50-watt) laser
cut in a minute?  How many little holes per minute can the X-Y plotting
table draw (when fitted with a pen)?

How many little round holes are there in a Wurl 105 organ roll?  The
perforator control file for 10-tune Wurlitzer 165 roll #6684 punches
exactly 102054 holes, but many are overlapping.  If the laser beam just
duplicates the data without replicating the webs and scalloped holes,
then there are only 38249 slots to cut.

You can see where my questions lead: a mechanical X-Y punch may be
faster, cheaper, and easier to maintain.  While I'm sure that paper
rolls can be cut with a laser beam -- for many years the textile
industry has cut cloth with this tool -- I suspect that a laser cutter
with the same production rate as a mechanical punch costs much, much
more than $5,000.

The advantage of the optical hole sensor is proven; maybe Spencer Chase
and Richard Stibbons will have advice based upon their experience with
optical scanning arrays.  They've also confirmed that a mediocre music
roll as input usually produces a copy of mediocrity: "Garbage In,
Garbage Out!"

Robbie Rhodes