I appreciate Robbie taking the time to clarify what he meant about
Ampico and Duo-Art tempo regulation, and how perfectly satisfactory
they are to him. (I'm having some fun with this right now -- don't
take it seriously).
Robbie said: " Both my Ampico B and the Duo-Art pumper have excellent
motor-speed regulation, and the effect is the same with either piano"
Great! That would seem to me, then, that his rolls do not have strange
acceleration characteristics, at least with Ampico and Duo-Art rolls
on them. They do not "bug" him.
In Robbie's "clarification" of what he really meant, yesterday he
said, "Virtually all 88-note rolls, and most reproducing piano rolls
_of popular songs_ (like fox-trots), are punched with constant beats
per foot. So, when I play these rolls on the Ampico B or the Pianola,
the music slowly gets faster."
Then Robbie, you ended by saying, that bugs you. "It's only about
4% speed-up over three minutes ... sometimes it bugs me, sometimes
it doesn't. But a metronome confirms that it's real." WOW!
All I can say (and now I am sincere) is how impressed I am at some
musicians, like yourself, who are able to be listening to a metronome
at the same time they are listening to a musical beat, and able to
discern a 4% change in rate! Absolutely incredible. When I realize
that, in the case of a mechanical metronome for example, in the
pendulum's full swing of about 3" 4% would be .120 inches. That is
the thickness of a piece of pouch leather, and just to think that
someone has the ear to detect that tiny offset is incredible.
I do not doubt at all that you did what you said you did. But just to
think that at the end of the piece, the downbeat, in effect, is leading
the metronome by .120 of an inch and you are able to detect it and tell
us exactly how much is absolutely amazing. I am stunned.
I would have just calculated the turns of paper, myself, and got that
figure. It just shows one thing -- there are lots of different ways
to skin a catfish.
[ Well, try the experiment yourself and tell me what you measure.
[ Select a long, jolly 88-note roll (such as a medley by Herman Avery
[ Wade) and count the musical beats per minute at both the beginning
[ and end of the music. A metronome will give you the numbers too.