I read about this a few years ago. Another piece of suppressed history. Mind you, having no available playback guaranteed it's obscurity.
This also points out how much modern "history" has been written by America. A louder voice, shall we say, promoting US advances & US "entrepreneurs".
I used a device, in the late 70s/early 80s that recorded to a paper disc - similar to the audograph of 1946. It was used in schools and wasn't too useful but it was a similar premise, a circular paper disc upon which sound was "written". It did play back though.

Last edited by rayc; 06/11/25 06:10 PM.

Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe