This is the “odd man out” in the quad world. Extremely ‘fine’ grooves were etched onto the vinyl record to provide frequencies between 35,000 and 50,000 hertz. The CD-4 demodulator sensed these high frequencies then converted them to a range of around 100 to 15,000 hertz. These frequencies were then sent to the amplifier and on to the rear channels.
A matrix decoder can not sense the high frequencies on a CD-4 record, it can only synthesize the stereo output of a CD-4 QuadraDisc LP.
My own experience with CD-4 led me to stick with matrix-type quads. To hear a quad sound from CD-4 encoded vinyl I just send it through my Vario-Matrix decoder and let it synthesize a quad sound. However, there ARE those who use and enjoy CD-4. Cai Campbell is a quad expert with an opposing view. Here is his opinion:
QADRAPHONIC TERMS, LINGO and ASSORTED BITS of STUFF
Decoders using ambiance recovery, such as early Dynacos, worked best on live recordings where the large area of the concert hall allowed natural reverberations and reflected sound waves to be recorded.
Radio-Electronics magazine in its March 1971 edition says the DynaQuad ambiance recovery unit first appeared in the spring of 1970. This product may have led the 70’s ‘quad craze.’
There’s three, yes, count ’em, three ways to provide a quad source to your super-duper quad hardware; reel-to-reel tape, 8-track tape, and vinyl record. Okay, you can use cassettes, etc that have quad recorded on them, but, I’m talking about original sources here.
Of the three formats, reel-to-reel tape is the rarest and it’s the most expensive to buy today. 8-tracks can be the cheapest if you find them locally at garage sales, thrift stores and used record/tape stores. I’ve bought quite a few quad 8-tracks for 10 to 50 cents each. Whadda’ deal!!! If you buy quad 8-tracks at Internet auction sites, be ready to pay top dollar. Records are the most commonly found quad software. Prices can vary greatly. Stuff that’s still-sealed gets the highest prices. For example, my still-sealed CD-4 Muscle of Love by Alice Cooper sold for 30 American dollars. Some quad records are readily available. The Doors Greatest Hits is a common one. There are oodles and gobs of ’em out there. Others are harder to find. I hunted all over before finding my groovy Nashville Skyline by Bob Dylan.
Various Variety of Udder Things
For a few years back in the 70’s, a number of radio stations broadcast in quad. Several different systems were used. The first attempts used 2 separate FM stations with one broadcasting the front channels and the other station the rear channels. WCRB & WGBH in Boston did this from 1969 to 1973. From ’73 on, WCRB went solo; airing SQ quad for several more years. Reports say an FM station could broadcast in SQ or QS quad by simply playing an encoded record, just like the ones available to the quad-buying public. Elementary Electronics in its July/Aug 1976 issue stated that SQ was broadcast by more than 300 FM stations and 70+ were spreading QS quad through the air. Neato!!!! The Jan. ’79 issue of the same magazine states that listeners preferred SQ with logic over every other broadcastable quad they listened to. However, the same survey showed that most listeners were unenthusiastic about listening to broadcasted quad. Hmmmmmmm.
More Nifty Information from the Incomparable Quad Bob
The first “modern” quadraphonic movie was The Who’s Tommy which was done in Sansui QS encoding……..the end credits of the movie even come up with a big “Sansui QS” for sound recording.
Star Wars was the first Dolby MP encoded release.
On August 29th 2000 the Quad world lost one of its greatest members….. Steve Wudtke.
Often known as Hood Crow or TWA Corbies on many letters, e-mails, newsgroup and bulletin board discussions, Steve was a constant source of information. His humor enlightened what may otherwise have been a sterile technical subject.