Thank you !
I have visited the link, read the article, and listened to the recordings.
I have a theory:
I think the original field recordings were made on 2-minute brown-wax blanks, using a two minute recorder, with the recording machine slowed-down to around 120 - 130 rpm.
Most early recordings ( pre- LP era ) have a "signature" that helps ID their format... almost nothing that rotates is perfectly round or perfectly concentric. Even if they were at time of manufacture, age and storage factors can cause things to go slightly out of shape.
When you play-back a 78 RPM disc record, or a cylinder recording, there is a characteristic frequency "beating" in the background, equivalent to the recording / play-back speed.
Commercial American cylinder recordings have a characteristic whoosh that "beats" at 160 beat/minute. This corresponds to the "high=spot" on the cylinder going past the stylus at regular intervals. If the record gets scratched across the recording surface ( ideally, perpendicular to the grooves ), you'll hear a "tick" at 160 beats / minute.
Same goes with a 78 RPM lateral disc or 80 RPM Diamond-Disc.
I think the same phenomenon is present in 45 rpm and 33-⅓ rpm LP records, but our ears / brains don't pick-up on the variances as easily.
At any rate, listening to the transcriptions, I hear nothing "beating" at 160 bpm. I do detect some background / damage noise at around 120-130 bpm, on all cuts, especially where there is surface damage ( scratching ).
All the recordings come-in around the 3-minute mark - but the singing is going-on before the cylinder starts and after the cylinder stops ( presumably ). If you have a four-minute blank, why stop around the 3-minute mark, leaving ¼ of the blank empty ?
If you slow the mandrel speed down to 120 rpm, the recording / playing time increases from the nominal "2-minute" mark to around 3-minutes. And, the fidelity is still tolerably good for music, certainly more acceptable than a 90 rpm "Language cylinder".
I think the original brown wax field cylinders were sent to Edison for transcription to Blue Amberols - I'm sure they would do special projects like this for a fee.
I believe during transcription, the original brown wax was played-back at 120-130 rpm, and the dub was recorded at the standard 160 rpm speed. So, the Amberols play at 160 rpm, with about ¼ of a cylinder-worth of "dead wax" at the end... or plsit between each end.
That's my big fat arm-chair theory on the matter.
