The sound company that, along with RCA, ruled over film sound for the first 40 years of the movie industry. Its equipment encompassed the whole chain: microphones, production recorders, re-recording consoles and machines to optical cameras, all of which were leased to studios in exchange for royalty fees.

By the 1970s — with the coming of manufacturers of specialized equipment such as consoles (Quad-Eight), mag machines (Magna-Tech) and stereo processes (Dolby Laboratories) — most licensees were not being renewed.