Optical sound - Wikipedia

Classic Optical Sound Recording

Phonautograph - Wikipedia

THE OPTIGONERS, The optigan and mellotron wheezing together.

Were video-audio recording cameras/apparatus available during the 1940s, or were the sounds captured separately or added during production? - Quora

Fiber-optic communication - Wikipedia

Optical table - Wikipedia

Audio bit depth - Wikipedia

In old movies or broadcasts always sound the same, Everyone has a very muffled and nasal sound to them. What caused microphones to produce such a uniformly weird sound? - Quora

Optical sound - Wikipedia

How to Connect a Television to a Stereo System

THE OPTIGONERS, The optigan and mellotron wheezing together.

What is the best way to visualize sound waves in real time? - Quora