Duo-Art Punch Advance
By Dan Wilson
This topic was the subject of an enormous article by Rex Lawson in the July 1996 issue of the Player-Piano Group Bulletin. It will probably appear in the AMICA Bulletin in good time, so there is no need for me to quote it at length (the acknowledgements of help with research take half a page !), but it is probably worth quoting a few salient points.
Rex has measured several hundred British and American production rolls and looked at quite a number of master rolls for evidence of acceleration. He says:
> It is clear that all Duo-Art rolls were designed to be perforated
> at either 42 or 63 ratchet (42R or 63R), meaning 21 or 31.5
> perforations per inch along the length of the roll. I have
> personally checked about 60 per cent of the classical series
> between 5500 and 7500 and I have found only three consistent
> exceptions so far, all of which are very long rolls from the
> early 1920s that have been compressed to 47R, using a smaller
> punch size. In these cases the rolls were nonetheless designed
> for 42R but were simply too long to fit on the largest spool,
> so the decision to compress them was presumably taken at the
> perforating factory and the repetition and the tempo suffer
> as a result.
> The very earliest Duo-Art rolls produced in Britain (in 1914)
> were also punched at 47R, with slower marked speeds, simply
> because the Hayes factory did not have the new 42R punch size
> in 1914, but all other copies of the same roll numbers are at
> 42R.
The two surviving Aeolian Co. perforators in England were saved from the bomb-damaged Universal Music Co. factory at Hayes by Gordon Iles in about 1948 when he bought the rights of the company, changing its name to Artona Music Rolls. I'm not sure if these are meant to be the "original Duo-Art perforators" mentioned earlier; the description would fit except that from a casting date of 1903 on one, they started life as 65-note perforators and throughout use by Artona and Auto- player only had a 47-tooth ratchet wheel giving 47 perforations to 2 inches, indicating they had been used for 88-note rolls, or Artona's subscription Duo-Arts (some made from un-issued Aeolian masters, so quite rare) with suitably changed tempos. The present-day Universal Music Co. (Mike Boyd) owns the machines (converted from mechanical cardboard-sensing to solenoid selection by Iles, so suitable for computer punching) and he is having 42-tooth and 63-tooth ratchet wheels specially made. The intention is that the 42-tooth wheel will be used on the second machine with Ampico-sized punches.
There is a lot in the article about paper speed. The clinching evidence is on the rolls: with Duo-Art, only a very few arranged dance rolls have equal bar lengths throughout the roll, while the remainder behave as though the start is on a 6.3" take-up spool -- i.e. 6 inches plus leader paper. Rex only touches on Ampico, but it seems there that nearly all the small rolls omitted deceleration and it had to be edited into the bigger rolls. Even so, acceleration of the music is often noticeable in Ampico recitals.
Surviving British master rolls show that the real-time Duo-Art recording perforator, which produced a roll as fast as the performer played and was alleged to cut 4000 perforations a minute, may have done so in America but only produced 3400 a minute in London. This is almost certainly thanks to the 60/50 Hz electric supply frequency difference !
The article has sparked off some argument from theorists who hold that the top spool brake has greater effect as the spool turns faster and has the effect of removing some of the acceleration. Measurements seem to indicate that this becomes true on instruments as they get out of condition, but is not true for well-maintained instruments. Run your Ampico rough ! A touchy subject !
Dan Wilson
[ Editor's Note:
[
[ 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.
[
[ 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? I hope the Duo-Art lore preserved in England can
[ provide some answers.
[
[ Robbie
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