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MMD > Archives > May 1998 > 1998.05.25 > 18Prev  Next

Mis-Punched QRS Roll
By Harvey Chao

Joel Hoshaw made mention of a mis-punched roll of "Humoresque".  I am
curious as to when he acquired it.  I too have a roll of this, C-103A,
acquired from QRS about a year ago.  To my  memory, my roll is
correctly punched in that I detect no notes missing or added -- at
least as well as my memory of how this piece is supposed to sound

My impression is that they punch multiple copies at a time, by,
perforation through multiple layers of roll paper simultaneously in
a single pass, hence I wonder if there was a bad batch?  As to:

> Don't bother, I [QRS?] can't think of anyone who would want 2 copies
> of THAT roll!"

-- "different strokes for different folks".

In the current case, I have a roll, part two of Le Miserables,
XP-311-C, whose perforations are visibly narrower (with ragged
edges) than any other roll I have (from various vendors and spread
over many years) and the particular notes that are problematic to play
are very short in duration.  The resulting holes for these "problem"
notes are very small rectangles/squares, on the order of 0.045-0.050"
W x 0.06" H.  This works out to about half the minimum specified area
of the smallest hole allowed for holes with a perforated width less
than 0.06".

This does get kind of interesting however in the context of the
specifications on hole sizes -

* One spec says:  "The diameter of the smallest perforations to be not
less than 0.0595" [ an area of 0.002827 sq. in;.]. and in that context,
the problematic holes appear to be in compliance in terms of area, even
if rectangular rather than round in shape.

* But, in the next spec:  "The length of the smallest perforation in
the music roll shall be not less than 0.083" when the width does not
exceed 0.06" [ area = 0.00498 sq. in. minimum]".  Since the perforation
width is 0.045-0.050, then the perforations at 0.06 long clearly
violate this requirement.

* The third spec regarding minimum hole size is functionally
consistent with the second spec:  "or if the width of the perforation
be greater than 0.060" then it's length shall be not less than is
sufficient to give an area of the perforation equivalent to that of a
perforation 0.0595" in width by 0.083" in length [0.0049385 sq. in.] ."

What the second and third bullets seem to say is that the minimum hole
sizes shall yield a hole area of 0.049 sq. inches. -- yet the first
bullet defines a minimum sized hole with an area about half that size,
0.0025 sq. inches.  The experience with my piano is that the 0.0049 sq.
inch holes play fine at any reasonable vacuum level, but that the
smaller holes only play (understandably) at really high vacuum levels
which may not be consistent with how the music (expression/volume)
needs to be played.

I am attempting to contact QRS and see if they have a "better"
perforated version of this roll that they would exchange.

Any reasonable comments?

Harvey Chao

(Message sent Tue 26 May 1998, 00:02:04 GMT, from time zone GMT-0700.)

Key Words in Subject:  Mis-Punched, QRS, Roll

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