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MMD > Archives > December 1996 > 1996.12.14 > 10Prev  Next


Ampico Roll Tempo Increase
By Craig Brougher

The subject regarding the lack of tempo compensation in Ampico rolls is also interesting from another angle. When I was just a little kid I visited my grandparents once a year. They had a player piano that I could not get enough of. Then when I got back home I had the rest of the year to try to remember how it played certain tunes. I learned to play by ear as a result, but, to this day, I cannot keep a steady tempo. I invariably speed up toward the end, just like the roll!

Later, when I started rebuilding reproducers, I noticed that the music on Ampicos and Duo-Arts kept a relatively constant speed. Maybe not perfect, I have never checked, but for sure its much better than the old 88-note player rolls. So there seems to be more to this than simple tempo compensation -- otherwise, the music on an Ampico would do the same percentage of speed-up that the same size (30-35 foot) roll does on the 88-note pumper player. Why, if no compensation were used, doesn't the Ampico enjoy the same (approx.) 15% change in tempo by the end of the roll? We realize, of course, that it would totally negate the authenticity of the music were it to have done that to the same degree.

When the same rolls are played on the Ampico B with the large take-up spool, I haven't noticed any difference. So if there is a difference, it must be mostly academic. Charles Stoddard was a very discerning gentleman. He was picky and loved high quality and small details in everything. I am surprised that if someone had such an important objection as serious as tempo buildup, that it would not have been addressed immediately.

We must also keep in mind that if there were, in fact, tempo problems with the Ampico, Aeolian Duo-Art would have certainly capitalized on it.

We shouldn't forget that both of these reproducing pianos appeared on the world's great concert stages together with the world's great musicians, performing -- live -- at same piano. They were called "Comparison Performances." I was told that, at Carnegie Hall, scorecards were given to New York music critics who then were to guess when the pianos were being played by the musicians, and when they were being played by the roll. Critics usually have a well-developed ear, and nobody at any time ever wrote a word about escalating tempos. The consensus was that it was really impossible to tell who was doing the playing, I understand.

Now I suppose there could be tricky ways around a tempo buildup problem on-stage for your average concert-goer, but I have met those who seem to have a metronome built into their brain, and fifteen minutes later can tell you if you are a beat too fast in a dozen measures. You aren't going to fool everybody.

I'm not that sensitive to tempo, so I have to say I can't really hear what you are speaking about. Could it be a combination of roll brake tension, transmission gearing, and air motor governor compensation that varies between pianos? I have corrected tempo problems also with the right lubricants as well.

By the way, if anybody is interested, the percentage of tempo buildup is proportional to the increasing length of the roll times the thickness of the paper. That in turn is equal to the difference in cross section area of the take-up spool and the paper when it is spooled on the take-up spool. So A' - A" = Ap = L X thk. Where A'= cross sectional area of paper plus take-up, A"= area of take-up spool cross section, Ap = Resultant cross sectional area of the paper itself. L = length of the roll, and thk + thickness. Percentages would be really easy to figure out as the roll paid out.

Craig Brougher


(Message sent Sat 14 Dec 1996, 16:09:30 GMT, from time zone GMT.)

Key Words in Subject:  Ampico, Increase, Roll, Tempo

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