>  rrhodes@foxtail.com (Robbie Rhodes, Etiwanda, Calif.) asks:

> Subject:       channel spacing

> Terry, based on your data I compute approximately 20 channels per inch
> *at the disk*.  This is the worst-case, in the treble section.  Is
> this figure correct?

Your question has provoked me into another closer look at the mechanics
of my Kalliope 25" disk music box.     Some of my earlier data is not
entirely correct because I overlooked that the 35 star wheels in the
treble segment each simultaneously actuate both side of the opposing
combs, effectively duplexing this section.    The star wheels in the
bass and bells section each each individually actuate single separate
notes.

Star wheels are all equidistant from each other throughout the full
length of the gantry, such that channel spacing works out to
approximately 11/inch

The tips of each opposing note are formed differently from the
bass/bells sections vs the treble sections:

Bass/Bells segments:

_____________________           ______________________________
                     |_        |_
_______________________|         |____________________________

Treble segments:

_______________________          _____________________________
_______________________|        |_____________________________

What this all means is that for channel design purposes, in a total
overall length of 10  15/16", mark off 121 equal spaces, with the
lowest bass note at one end (center) and the highest bell note at the
other end (rim).

From the rim, positions 13, 49, and 86 are occupied by the height
idler wheels in the star wheel gantry.    There are no musical notes
perforated into the disk at these points, where are also located
pressure idler wheels on the top side.

The perforations in the disk are each approximately 1/8" long, and
their companion underside projections are located on the trailing
edge of the perf.

Hope this clarifies some of the data.    Let me know if you need any
more data.

Regards,

Terry

Terry Smythe                    (204) 832-3982 (voice/fax)
55 Rowand Avenue                smythe@mts.net
Winnipeg, MB, Canada   R3J 2n6  smythe@freenet.mb.ca
Home page: http://www.mts.net/~smythe