used by enthusiasts but required large individual reels and tapes which had to be threaded by hand, making them less accessible to the casual consumer. Both RCA and Bell Sound attempted to commercialize the cartridge format, but a few factors stalled adoption, including lower-than-advertised availability of selections in the prerecorded media catalog, delays in production setup, and a stand-alone design that was not considered by audiophiles to be truly hi-fi.

The