Re: Duo-Art Punch Advance
By Dan Wilson
Robbie said:
>[ Kudos to Rex Lawson for his research, Dan. In order to confirm his
>[ findings on acceleration, could you please tell us the thickness of
>[ the paper which he observed? Rex says that the short length of
>[ leader paper wrapped upon a 6-inch diameter take-up spool will
>[ increase the diameter by 0.3 inch. Are you certain? This seems
>[ to be terribly thick paper.
No, he merely described master rolls (jargon: "pattern rolls") as having an acceleration characteristic consistent with a take-up spool of 6.3 inch circumference. The pattern rolls were folded under at the start and also ran for some time before the performer started, since the editor at the desk did not himself start it, but used a speaking tube to the perforator room.
The paper of pretty well all of the original rolls he examined was 0.00325 inch thick, but when played they exhibited an acceleration consistent with 0.00330 inch, doubtless thanks to trapped air.
[ and also to "puckering" at the edge of the punched hole. The
[ contemporary paper used by QRS and others is thinner, with effective
[ thickness 0.00275 inch after perforating. -- Robbie
>[ According to the history in the book "The Ampico Reproducing Piano"
>[ (publ. MBSI), all music rolls at Ampico were created and edited for
>[ production using synchronous sprocket-drive master rolls. I believe
>[ that Duo-Art used cardboard masters. Were they also sprocket-drive?
>[ Did the Duo-Art high-speed perforating-recording machine produce a
>[ roll with sprocket holes?
The card masters (jargon: "stencils") were the same style in UK and USA, but with Duo-Art they incorporated in the punching the necessary deceleration. Rex doesn't say in the article if they were sprocket- driven and I've not seen one, so I can't say.
There is an interesting note about trying to record dynamics. Apparently several experiments took place even before the Duo-Art was launched, which came to nothing not because it couldn't be done, but because what was wanted "up front" was the coding that would produce those dynamics on a Duo-Art instrument. (Or as we now know, the subdued- level version of the dynamics which the customers would accept.)
After H. Creary Woods (the American editor) had coded a number of rolls by hand in desperation, he got to recognize what pianos did with certain dynamic steps, and realized that, going backwards from this, he could "code" a performer in the same way in real time. Thus came about the well-known editing desks that appear in publicity shots of celebrities recording in both London and New York.
The two knobs are apparently control Accompaniment and Theme powers, with the actual placement of theme "snakebites" being done later to taste. Rex suspects that when the real-time master roll was replayed to the artist minutes later, "theme" was added, Pianola-style, by the editor at the desk, to achieve a reasonable approximation of the finished result. Since celebrities could not be expected to continue repeating disputed sections for accuracy, it was after this replay that the editor got out the sheet music and got the artist to make notes on it illustrating criticisms.
Prior to the desks being installed, the sheet music was used for all the annotation, as I think happened a lot at Ampico. Some of this detail is not in his article, however, but are conclusions that have been derived from poring over the many patents and letters. American copy masters were sometimes "juiced up" a bit in London to compensate for the less dramatic hammer-lift in European pianos. (This was noted by Duo-Art pianist Harold Bauer, who had a keen ear).
Dan Wilson
[ I heard a variant story about the "recording desk", wherein the
[ operator also had foot-buttons which, while pressed, caused
[ "snakebites" to be punched coincident with each note played. Later
[ the editors would patch-over the unneeded accents. -- Robbie
|
|
|
Mechanical
Music Digest™ Archives
