[Scott Dorsey]

Mike Rivers wrote:
On Thursday, April 30, 2015 at 11:17:32 AM UTC-4, JackA wrote:

I'm far from an expert on Quad' formats, but I do not believe any provide=
d well isolated discrete (4) channel sound, like (later) digital formats.
Seem to recall reading about a 40 kHz or so carrier that contained the "r=
ear" channel information.

All of the phonograph record quad formats were "matrixed" because there are=
only two outputs from the stereo phono cartridge. Tape formats, however, w=
ere not. The TEAC 3340, the tape deck that, thanks to Dick Rosmini, pretty =
much started the home studio revolution, was originally designed for record=
ing and playing back discrete four channel quad recordings.=20

QS and SQ were, like Dolby Surround, matrixed formats.

However, CD-4 did in fact have a stereo subcarrier containing rear channel
information, which gave you four discrete channels. For the first few plays
the separation was pretty good but as the record wore it fell apart pretty
quickly.

4-track tape was pretty popular, though. There were a lot of prerecorded
4-track tapes out there with surround mixes. (Do not confuse with quarter
track, which sadly some record companies called "4-track" on the boxes.)
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."