For UK readers, BBC4 are now re-showing the 2015 series Sound of Song. If you are interested in the history of sound recording and the ways in which changes in technology led to vast changes in popular music in the 20th century (and, as you are reading this, I’m guessing you are interested) then it’s as good a place as any to start. The first episode even features the recording of a new wax cylinder, and a demonstration of the effects of microphones on singing technique. My only criticism is that too much was cut out, but the 100-hour documentary series I would like to see is probably not realistic on current BBC budgets.
Episode 1 can be seen here – https://www.bbc.co.uk/iplayer/episode/b04y4qpt/sound-of-song-1-the-recording-revolution – for the next 28 days. Further episodes will go up in the next few weeks.