(1972-05) Billboard - New RCA CD-4 Vinyl

[kfbkfb]

https://www.worldradiohistory.com/Archive-All-Music/Billboard/70s/1972/Billboard 1972-05-06.pdf

Strangely, an AES paper in 1974-09 stated that CD-4 discs were being made with regular vinyl (various articles before 1974 mentioned using a more durable vinyl for CD-4), it would be interesting to find out how many different vinyl formulations there were for USA made CD-4 discs.


Kirk Bayne

 

[Doug G.]

What a coinkydink. I remember reading that article on the front page, "RCA Slates New LP Mix" way back then and wondering what the heck they meant by,"The new record will have a slightly different curvature..." I didn't know then, never found out and still don't.

It may have meant a different vertical curvature, like where the Gruve-Gard started and ended but I don't know.

Doug

 

[par4ken]

https://www.worldradiohistory.com/Archive-All-Music/Billboard/70s/1972/Billboard 1972-05-06.pdf

Strangely, an AES paper in 1974-09 stated that CD-4 discs were being made with regular vinyl (various articles before 1974 mentioned using a more durable vinyl for CD-4), it would be interesting to find out how many different vinyl formulations there were for USA made CD-4 discs.


Kirk Bayne

Where did it say that regular vinyl was being used for CD-4? Implied maybe? The article states that with the introduction of the Quadradisc a firmer improved compound was to be used. The new records were still Dynaflex, just not as flexible! I would think that it was really JVC Super vinyl or something very similar. It also states that a similar curative is now being used by Columbia records.

By the way I love Dynaflex records, despite their lightweight they sound great. No need for those ultra heavy 180 gram plus LP's that they put out now!

 

[Doug G.]

Rethinking, maybe the "curvature" thing was a mistake/misprint and it should have read "curative" there. That actually makes more sense, relative to the "firmer compound" wording.

Doug

 

[Old Quad Guy]

Here’s the article reformatted:

May 6, 1972

RCA Slates New LP Mix

By ROBERT SOBEL

NEW YORK-
With the introduction of its new Quadradisc. RCA Records will embody a firmer, improved compound in its new record that it claims will enhance considerably the quality of the sound.
The new record will have a slightly different curvature and. because of the firmer compound, will give longer life to the groove and will provide a less flexible Dynaflex record. An improved stylus will spur the pickup of back channels and will give longer wear to the grooves, according to an RCA spokesman. A new demodulator, developed by JVC, has been refined to keep the needle on track so that it can pick up the sub-carriers which activate the two back channels.
RCA will make all newly recorded Quadradisc product utilizing the new compound and the other two innovations noted. A regular release is planned for the fall and target date for all records to go Quadradisc has been set by this time next year. A similar cur-vative is now being used by Columbia Records.
The record will be demonstrated during the IMIC conference being held in Acapulco this week.

 

[kfbkfb]

Where did it say that regular vinyl was being used for CD-4?

https://pspatialaudio.com/CD-4 wear.htm
^^^
Bogantz and Khanna stress that, although the new compound recipe was made publicly available to the plastics industry by the time of their paper, companies other than RCA were still pressing CD-4 releases with standard stereo compounds at the time of publication.


It's puzzling - the WEA group was pro CD-4, but this statement in the 1974-09 AES document indicates that the WEA group was using regular stereo vinyl compounds for their CD-4 discs - that doesn't seem to me like a good way to promote CD-4.

Looks like the progression of vinyl compounds for CD-4 was RCA (moderately more durable) -> Keysor Q-540 -> RCA (much more durable) Quadradisc vinyl.


edit:
I see I posted something similar a while back, should have checked instead of reposting basically the same info.


Kirk Bayne