A Mystery Blue Amberol

[RodPickett]

I'm in possession of a 4-minute Blue Amberol, etched as "Ed. EX. No. 16 4/3/30", presumably for Edison Experiment No. 16.

 

Recorded are a series of short-duration "tone tests", each different.

 

An Internet search for "blue amberol tone tests" revealed the following; however, these all likely refer to the tone-test cylinders dated 1929 or earlier.

 

 

Attached are photos for reference and a link to a crude acoustic recording made with the smart-phone voice recorder.  It was played on an Edison Fireside, Model K reproducer.

 

WARNING:  The recording is painful to hear.  Comments welcome.

 

 

 

 

[phonogfp]

I'd rather listen to this than to Uncle Josh!

 

I wonder what the Edison technicians would have been testing for in April 1930?    Possibly the steadiness of an electric motor?  If so, it would have been for an Ediphone.  Whatever the circumstances, it's an interesting mystery.

 

George P.

[RodPickett]

This comment was received from an earlier conversation:

 

 

"Wonder what rotational speed Theodore E. had in mind?  90, 100, 160, or whatever?

 

Anyway, at the rotational speed you are playing it with, even though your governor is a smidge inconsistent, the pitches of the tones are:

A  above middle C, followed by the next higher C sharp, next higher G sharp, next higher C sharp, and then the next higher E.

 

These tones will however let you hear any waver in the reproduction due to even a minuscule amount of wow. Might be a great way to test a recording machine that Theodore’s team would be using to record tones for perfect consistent pitch.

 

Another thought:

 

The US Signal Army Corps was working with TAE Inc.  to produce  morse code teaching and testing cylinders in 4 inch and 6 inch lengths and they use tones of this sort. Was this experimental series of cylinders used “in house” to develop the morse code cylinders for production?"

 

[Fran604g]

Interesting BA, Rod. I could see this as a calibration device, but to what end? Test tones can be used for many applications. I hope more information is eventually uncovered.

Edited 1 hour ago by Fran604g