The nearly square shaped cartridges are among the largest ever built. More than 24 hours of playback fits on a single cartridge. The music distributed by 3M consisted exclusively of mono recordings by company's own "3M Orchestra". The tape is ¼ inch wide and is played at 1⅞ inches per second. The cartridge consists of a reel-to-reel mechanism intended for playback only. Internally, the cartridge contains two 8⅜ inch tape reels, tape guides, rollers, and a reel brake. The reels are stacked on top of each other vertically and counter rotate during operation. After passing over the tape head, the tape loops over a roller in the cartridge to change its direction back to the takeup reel.
All offered machines are playback only. The first models 94BG and 94BZ were offered in 1965 and bundled with two cartridges of the customer's choice for $429.00 USD (with inflation in today's value: $3411 USD). Each machine is equipped with a jack for 8 Ω speakers (at a maximum of 6 W) and a microphone jack for public address announcements.
The machines played continuously using an auto-reverse mechanism. As the tape reaches one end, the reverse mechanism activates and changes the drive direction. The tape head moves to the other side and the mechanism shifts pinch rollers. The design does not require the head to turn over; instead, the entire head changes position to play the tape at the other side of the tape path.
In 1970, 3M introduced the Cantata 700 Mark II, available only by lease.
Variety of Cartridges
- Variety Library V-168
- Rhythmic Library 165
- Melodic Library 165
- Rhythmic Library Series II 266
- International Rhythmic Uptempo IR-169
- Techmoan: Retro Tech: This 1960s BGM Machine played the Biggest Cassettes ever made, uploaded to YouTube on 11 May 2016
- Billboard 23 October 1965, p.46
- "What's New: A Picture Roundup of New Products and Developments". Popular Science. Bonnier Corporation: 109. January 1970. Retrieved 6 April 2017.