>[ In music rolls for Wurlitzer band organs, the bass drum hole is
>[ advanced 0.050" to 0.100" ahead of the notes, which presumably
>[ corrects the error of a bass drum beater with 90 to 180 ms. delay.
>[ The compensation observed on Wurlitzer rolls that I've seen isn't
>[ consistent, and many band organ owners don't know how to adjust the
>[ beater travel distance and the valves and springs to eliminate the
>[ timing error.
It is probably worth mentioning that the tracker bar hole for the bass
and snare drums is raised one hole height above the note playing holes.
This was to allow for the beater to reach the drum head in time with
the notes being played. I was not aware that the drum perforations on
the roll were also moved for timing purposes.
[ Matthew Caulfield wrote to me about offsets in Wurlitzer 165 band
[ organ music rolls: "Some rolls show a clear advance over the rest
[ of the measure by about a half-punch, other rolls do not. For
[ example, roll 6637 doesn't, roll 6684 does. Only a study of many
[ original green-paper rolls would shed light on this practice and
[ any pattern in its use, I suppose."
[ Matthew's original production copy of Wurlitzer 165 roll number
[ 6684 (issued in February, 1941) consistently displays one step
[ advance of the bass drum commands compared to the note commands.
[ This is the only roll I have precise measurements for. (In
[ recut rolls the hole positions aren't accurate enough to easily
[ determine if offset was or wasn't used in the original roll.)
[ Don Rand once showed me a Wurlitzer 165 tracker bar in which the
[ offset bass drum hole had been brutally enlarged with a dull file
[ by someone who evidently was annoyed by the timing error. Don
[ noted that instead the bellows and valves should have been rebuilt
[ and properly adjusted.
[ -- Robbie