The Victor Orchestra crowds around the recording horn
For most of the time humans have been on our planet, music has been ephemeral. If you played or sang the music yourself, once you stopped, it was gone forever. The same was true when professional musicians came on the scene.
So it must have seemed like a miracle when commercial music recordings appeared at the beginning of the 20th century. For the first time, this ephemeral art could be captured and frozen, able to be brought to life again at the whim of the listener, and produced on a large scale. We are now so used to sound recordings, in multiple technologies and formats, that it might be difficult to imagine just how extraordinary this must have been.
The sound reproduction system that was used initially was acoustic. Sound waves were captured by means of a large horn which funneled them towards a diaphragm that vibrated in response, and then a stylus etched those vibrations into a wax disc revolving at 78 rpm (revolutions per minute). The disc was then reproduced in shellac, and, to play back the recording, a needle/stylus ran over the grooves in the spinning record, causing the diaphragm to vibrate and create sound waves. In its most simplified form, that was it!
All commercial sound recordings from 1901 to 1925 used the acoustic method described above. The next advance occurred with the introduction of electrical recording. Microphones allowed more focused sound capture, and amplifiers could increase the strength of the electrical signal, which then could be recorded onto a disc. The result was a higher quality recording with an improved dynamic range.
Electrical recording to 78 rpm discs continued until 1948, when the next advancement, the LP (Long Playing) record, revolving at 33 1/3 rpm, was introduced.