Quadraphonic sound
Four channel quadraphonic surround sound can be used to recreate the highly realistic effect of a three-dimensional live concert hall experience in the home.
Quadraphonic sound was a commercial failure when first introduced due to a variety of technical issues and format incompatibilities.
The introduction of home cinema products in the 1990s were first intended for movie sound, but also brought multi-channel music reproduction into popularity again.
Many four channel recordings from the 1970s have been reissued in modern surround sound systems such as Super Audio CD, DTS, Dolby Digital, DVD-Audio and Blu-ray.
Multichannel home audio reproduction has experienced a revival since 2000 and new four channel recordings have also been released to the public since this time.
[2] Early attempts to reproduce four channel sound for home playback began with audio laboratory engineers in the late 1960s.
Producer Thomas Mowrey,[3] initially working at the Eastman School of Music, was one of the pioneers of classical quadraphonic recording.
Many quadraphonic recordings in the 1970s used matrix technologies to encode and decode four channels of audio information in a 2-channel medium, usually an LP.
Sansui's QSD-series decoders and QRX-series receivers were very good, even synthesizing left-right stereo into a ⋂ horseshoe topology.
However, all these came too late in the game and were too expensive or difficult to procure for public purchase, to rescue matrix quad from obscurity.
By the early 2000s more sophisticated "discrete" multichannel systems had mostly replaced matrix technologies, providing a higher level of performance and full channel independence.
For classical music, producers have typically preferred an effect where the orchestra appears in stereo in only the front channels, and the natural reverberation or echo of the concert hall is in all the speakers.
[13] The original four channel recording was released on matrix LP and 8-track tape, and reissued on the Super Audio CD format by Dutton Vocalion in 2018.
While quadraphonic effects have sometimes been considered artificial, musical enjoyment can be dramatically enhanced by more fully involving the listener.
Derived (2–2–4) formats are simple and inexpensive electronic solutions that add or extract rear ambience or reverberation sound channels from stereo records i.e., studio reverb, audience applause, etc.
But with poor decode performance, these systems failed to match the accuracy or channel independence of later matrix formats.
The differences between the early and late matrix systems were so vast, it made decoding DY/EV-4 with either SQ or QS decoders with accuracy impossible; the results often being a smeared or poorly defined sound stage, which could be vastly different from what was intended by the producer or recording engineer.
The third major format for four-channel vinyl LPs, known as CD-4 or Quadradisc, was devised by the Japanese JVC Corporation along with its US counterpart RCA Records.
A fully discrete system, it eschewed matrix technologies in favor of a method similar to the encoding of stereo FM broadcasts.
Because the CD-4 system maintains four independent signals throughout the process it can accurately reconstruct the intended four-channel sound field.
The short-lived system suffered from incompatibility with regular stereo playback due to phase differences between the left and right channels.
The format was almost identical in appearance to stereo 8-tracks, except for a small sensing notch in the upper left corner of the cartridge.
[28] KEXL-FM ("KEXL 104.5") (San Antonio, Texas) broadcast in "Quadraphonic" in the early to mid 1970s from its studios in a high-rise office building off Main Plaza.
[29] Seattle station KIRO-FM 100.7 later branded as KSEA 101 broadcast several hours daily between 1973 and early 1976 encoded SQ quadraphonic music.
[30] Sunday morning's "Music and the Spoken Word" from Salt Lake's Mormon Tabernacle was in SQ quad.
[30] Matrix H was developed by BBC engineers in 1977 to carry quadraphonic sound via FM radio in a way which would be most compatible with existing mono and stereo receivers.
This was based on tolerance zones designed to include modified versions of both Matrix H and the prototype two-channel encoding of Ambisonics, known as System 45J.
Subsequently, the Nippon-Columbia UMX matrix was brought into the standard, leading to the final UHJ name now associated with Ambisonics.
In 1967 the group Pink Floyd debuted its custom-made quadraphonic speaker system and performed the first-ever surround-sound rock concert.
[38] The controller, which was usually operated by Richard Wright, allowed the musicians to place sounds in any speaker and move them around the listening area.
