Quadraphonic Sound - History

History

The first medium for 4-channel sound was the quadraphonic reel-to-reel tape, standard in European electronic-music studios by 1953 and introduced to the American market by the Vanguard Recording Society in June 1969. RCA Records followed, in April 1970, with its announcement of Quad-8 or Quadraphonic 8-Track Tape (later shortened to just Q8). These eventually appeared in Sept. 1970.

"Quad" (as it became known) did not remain restricted to the discrete-channel format used in the quadraphonic reel-to-reel or Quad-8. Quadraphonic vinyl albums appeared, which used several different and incompatible modes. The first of these, known as QS or Command Quadraphonic, was developed by Sansui Electric. A so-called matrix format, it utilized four sound channels which were "encoded" into two stereo album tracks. These were, then, "decoded" back into the original four sound channels. The QS system debuted in the United States in March 1971.

The second Quad vinyl record format, known as SQ, also utilized a matrix-type system of encoding and decoding. It was developed and marketed by Columbia Records and Sony and entered the US market in April 1971. The SQ format was also used by companies such as EMI in Great Britain, who pressed several SQ album releases. The sound separation of the SQ system was greatly improved by the introduction of SQ Full Logic decoding, in 1975.

The third major format for 4-channel vinyl LPs, known as CD-4 or Quadradisc, was devised by the Japanese JVC Corporation along with its United States counterpart, RCA. This quadraphonic format was first marketed in the United States in May 1972. A fully discrete sound mode, it eschewed the previous matrix systems in favor of a more complex -and sonically separate- method of 4-channel reproduction. A high-frequency "carrier wave" instructed a "CD-4 demodulator" on how to separate the four sound channels within the vinyl album.

Audio on vinyl records was problematic because one of the systems was based on discrete sound channels (allowing for full separation of the four original recorded channels, albeit with restricted high-frequency response and reduced record life), while two others were matrix encoded into two tracks that would also play back in standard, two-channel, stereo on normal audio equipment (so-called 'compatible' quadraphonic).

There were some experiments done with radio broadcasts (e.g., a Cliff Richard concert by the BBC), but they were short-lived. One radio series, Double Exposure, was briefly syndicated throughout the United States to various FM stations; it was made up of jazz, rock and pop music that had been commercially released in one of the quadraphonic record or tape systems. One of the longest-lived radio broadcasts was WQSR-FM "Quad 102½" in Sarasota, Florida. Throughout most of the 1970s this station broadcast a signal which could be tuned as two separate stations with conventional stereo receivers. In addition, San Francisco classical music station KKHI broadcast the San Francisco Opera in 'compatible' (that is, matrix encoded) quadraphonic format during the 1970s as did Chicago station WFMT's live "Chicago Lyric Opera" broadcasts.. KRMH-FM ("Good Karma Radio")(San Marcos/Austin, Texas) broadcast in "Quad Stereo" in the early 1970s from its studios and transmitter near Buda, Texas.