Back in the 1970s, the record industry had a first go at surround sound, with four-track recording. I'm not going to say anything here about my views of the technical aspects of this. Although you could buy four-track tapes of some releases, most were issued in one or other of a number of similar but incompatible matrix encodings which were published as LPs which could be played in stereo or decoded to four channels (with less separation then the original master recording, of course). This development fizzled out fairly quickly, because the public was not ready to double the amount of equipment in their living rooms so soon after stereo had become universal, and also because the complexity of handling multiple matrix systems, with somewhat mediocre results, just put them right off.
Considerably more people would be able to play these recordings now, if they were available in four-channel form (AC3, DTS, DVD-A, etc).
The Quad Blog is dedicated to making them available. The author (who lives in my city) is making the best possible decodes of old matrix recordings from LPs he's collected, and rips that people have done for him; he has also made available some rips from four-channel tapes, both consumer and master, or pointed to commercial releases of these.
The repertoire is wide ranging - Berlioz (Requiem - written for surround performance), Pink Floyd (Dark Side of the Moon, et al), David Munro, Tangerine Dream, Frank Sinatra, Beethoven, Black Sabbath.... well over 100 albums so far.
