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Edison's patent drawing of phonograph
Our final Techno Challenge question is on the phonograph.
To learn more about recording technologies visit David Morton's site  Recording History.

To answer Techno Challenge #4, click here.

Phonograph recordings came as 33 1/3, 45 and 78s. What do these numbers refer to?  RPM, revolutions per minute or the number of times the disc spun around in one minute.  The  lower the speed the more music the disc could hold.