Don't know if these have been mentioned here. The Boston Symphony posted a
link to the first video today and I found the rest at the Internet archives
The following are some films produced by RCA on how records are made, an
introduction to stereophonic sound, & Living stereo.
How records are made.including some footage of the BSO under Munch,
presumably recording Tchaikovsky's Romeo & Juliet.
Must have been used as a demo for stereo at hifi shows. The end presumably
is meant to be synched with a stereo recording Grofe's Grand Canyon Suite.
An introduction to stereo & "Living stereo"