Design Dinosaurs: 6 The eight-track cartridge

THE AMERICAN broadcasting industry invented the loop cartridge in the early Fifties to cut the laborious manual cueing of reel-to-reel tape recorders every time there was a break for commercials; with a loop cartridge, the tape was automatically re- cued at the end of the break for the next one. The potential for wider use was obvious, but there was a hitch: the 'jingle cartridge' lasted just three minutes.

In the early Sixties, commercially produced cartridges began to appear which halved the running speed from 7 1/2 in per second to 3 3/4 in per second and used the wide 1/4 in tape to carry four parallel mono (or two stereo) tracks. This took playing time up to around 30 minutes: usable, but still short of the standard LP length necessary to interest major music distributors. In 1964, electronics wizard Bill Lear - already inventor of the world's first car radio and of his eponymous jet - extended this idea to eight tracks. The Lear Stereo 8 played first one pair of stereo tracks and then, after the head had moved a short distance, another. With a certain amount of clicking and whirring, and with a slightly longer tape crammed in, Lear cartridges could play for up to 90 minutes. Ford installed the system in the 1965 Thunderbird, and in the same year kits were shipped to Britain.

For a time the eight-track seemed to have the car audio market sewn up. Phillips had introduced their Compact Cassette for dictating machines in 1963, but it hadn't been taken seriously because the narrow tape and slow running speed caused intrusive tape hiss (a problem which didn't affect the faster-running eight-track). Then, in 1969, Ray Dolby patented his noise suppression system, and all that changed.

Cartridges were not only bulky by comparison. Their complicated playback drive mechanism responded to every bump in the road, rewound at a snail's pace and didn't fast forward at all; and you could always hear just enough of the adjacent track in reverse ('cross-talk') to make you think that you might as well be listening to the interference on your old car radio.