Quadraphonic

The buyer quadraphonic enthusiasm started with the launching of the SQ system by the CBS Technology Center in 1971. CBS was a main producer of vinyl records at the time, and several were offered with SQ encoding. Full quad was launched a few years ago using four channels of distinct audio on reel-to-reel tapes. It was followed by Receivers and Decoders with integrated SQ circuitry. Launched in America in September 1970 as the Quad-8 or Quadraphonic 8-Track, "Quad" didn't remain limited to the distinct channel format used in the Quad-8. It emerged in many different and mostly incompatible formats on different media. Quadraphonic audio could be taken from vinyl records, eight track tapes, and reel-to-reel tapes.



Quadraphonic sound uses four channels in which speakers are located at the corners of the room, reproducing signals that are (fully or partially) independent of each other. Quadraphonic audio was one of the first user offerings in surround sound. It was commercially failed due to several technical problems that were resolved too late to protect the technology from adversity. The format was very expensive, need extra speakers, and undergo a low standard format for LP records. The grow of home theater products in the late 80s and early 90s put again the multi-channel recording formats back to the front, although in a totally different and perhaps unanticipated type. Only a few quadraphonic recordings were completed before its end, and some of these recordings were afterward reissued on CD in Dolby Surround.

The quadraphonic music was preset with baseband sum and ultrasonic phase-modulated subcarrier different signals (encoded in the 18 to 50 kHz range) similar in perception to the system used in FM stereo, on the typical stereo channels of vinyl, which also had the unwanted side-effect of restraining the high frequency audio response to 15 kHz with a 16Khz 'pilot' tone. A special high-frequency cartridge and stylus was necessary to play back the record, along with a CD-4 demodulator and the common quadraphonic receiver or amp. This system created extra wear and tear, so JVC brought "super vinyl", a very sturdy type of record. The cartridge used had a shibata form stylus and an enhanced frequency response. Afterward, linear contact styli were developed that enhanced the quality of CD-4 systems. Quadraphonic sound was died very early, caused mainly by the challenging and contrary systems, and the expense of the extra circuitry such as decoder, two additional power amps and speakers. At the time, the most of such circuitry was applied using separate mechanisms, driving up the material and labor expenses. Multi-channel stereo in theaters was a considerably better hearing experience, and benefited from consistency, dissimilar to quad. The multi-channel stereo theater experience was finally brought into the home and known as 'home theater system' that is on sale nowadays.