Found, at last: the original QUAD CD

[winopener]

Here, a Pioneer prototype:

http://www.thevintageknob.org/INVISIBILIA/DAD/pioneer-PD1proto.html

a look here at the whole page is *very* recommended:

http://www.thevintageknob.org/INVISIBILIA/INVISIBILIA-main.html

 

[timbre4]

Neat-O!

Appreciate the links

 

[jdmack]

Wow! I remember that the first CD burning software my company owned had an unsupported setting for 4-channel CDs. But I had forgotten about that until seeing this.

J. D.

 

[JonUrban]

Very cool. Thanks for posting the link.

 

[Key]

Wow! I remember that the first CD burning software my company owned had an unsupported setting for 4-channel CDs. But I had forgotten about that until seeing this.

J. D.

Yeah, there is a 4chan flag for CD-DA that always puzzled me. I *think* I found out that it was indeed for quad, but that it was limited to the same bandwidth of CD-DA which means 22.05 sample rate. So I guess it would have been 20Hz - 11kHz frequency response. Understandable why that wouldn't take off.

 

[winopener]

IIRC the specs for quad cd were: 12 bit, 32KHz s/r, 4 channel.
That does make for a bitrate close to the stereo cd (16bit, 44.1 KHz s/r, 2 channel).
Quad cd sounds like a compromise, however cd4 was 15KHz and the 12bit issue was aligned with the PCM recorder of the era.

 

[jdmack]

IIRC the specs for quad cd were: 12 bit, 32KHz s/r, 4 channel.

Hmm. Interesting. That's also the 4-channel specs for the DVCam video format.

J. D.

 

[Lucanu]

Here's something about 4-channel cd on Wikipedia, I don't know who wrote this but it's very interesting

http://en.wikipedia.org/wiki/Four-channel_compact_disc_digital_audio

and http://www.ee.washington.edu/conselec/CE/kuhn/cdaudio2/95x7.htm (this link doesn't seem to work)

and http://developer.apple.com/document...ack/CompositePage.html#kDRAudioFourChannelKey