Laserdisc's CX audio vs PCM sound.

[Ianthe80skid]

What were the main differences? I know CX was analog and PCM is digital but did they have the same frequency response? A buddy of mine once told me that older laserdisc sound really sucked without having PCM, Dolby or DTS sound.

 

[Duane]

CX is a noise reduction circuit.

 

[JoeESP9]

It depends on the model of the player. The DVL-919 supports AC3 (Dolby Digital) and DTS output. They're both PCM signals.

 

[1tumbleweed]

When laserdisc was introduced, CX was the best they could do, being pre-digital (it also addressed a video interference problem). When digital sound came into being, every laserdisc (AFAIK) came with digital sound instead (before AC3 or DTS existed).

https://en.wikipedia.org/wiki/CX_(audio)

Happy trails,
Larry B.

 

[Ianthe80skid]

I didn't know CX was a noise reduction scheme for Laserdisc. I honestly just thought thats how it was encoded on to the disc. I now see that it was a FM carrier signal that contained the audio. I'm still trying to figure out the actual frequency response of those older Laserdisc's analog audio signal. I wonder if it was similar to cassette, possibly 50 Hz - 16 kHz?

 

[twiiii]

I have my CLD manuals and 919 manuals none give specs for analog sound. What I have read on the internet hasn't helped either. But unless Pioneer and MCA had access to the original with magnetic sound optical audio was very poor and CX would be more than adequate.

 

[steerpike2]

Laserdisc, or Laservision, predates CX. Original discs from the 1970s and early 1980s will not be CX encoded.

The quality of the FM audio would be player dependant, but from a technical standing, the FM process with CX would easily allow a frequency responce of 20-20,000Hz, >80dB signal to noise ratio, and wow and flutter at less than 0.005%. Far better than any compact cassette, better than any broadcast of the time, and better than the videotape that the Laserdisc was made from.