Audio Formats - I'm Confused

[mrdenn1s]

I'm sure someone can point me in the right direction but here are my questions:

1) Is PCM uncompressed?

2) Is PCM what you find on audio CD's?

3) Why is PCM on 2 channels on DVD's yet Dolby is in 5.1?

4) Is Dolby not as good like for like as PCM?

5) Is DTS better than Dolby? Why?

6) If listening to a Music DVD, will 2 channel PCM or 5.1 be a better sound quality?

Thanks Guys

Dennis

[Shonky*]

You need to clarify Dolby. Dolby can be anything from the very old Dolby Prologic Surround (analogue) all the way up to brand new lossless Dolby TrueHD. Likewise DTS HD-MA is better than DTS.

1) Yes

2) Yes - 16 bit 44.1kHz 2 channels

3) Example? I'm not aware of DVDs with 2 channel PCM. Often extras will be "AC3 2.0" which is still a Dolby compressed format. If there really is a PCM 2 channel DVD it would/should be better than AC3 2.0.

4) In the sense that PCM is generally two channel only, "Dolby" (AC3) is better. Again depends a lot on which "Dolby" you're talking about. Dolby TrueHD is just as good as multichannel PCM

5) Yes theoretically. AC3 (what you're calling "5.1") can only run up to 640kbps compared to 1.536Mbps for DTS. But AC3 could just be more efficient. Both companies claim they are good enough to be indistiguishable. However they then came out with TrueHD and DTS MA respectively.

6) Depends how it was recorded. If recorded specifically in surround AC3 5.1 is probably better.

Have a read of these:

http://en.wikipedia.org/wiki/AC3

http://en.wikipedia.org/wiki/Digital_Theater_System

Edited September 16, 2008 by Shonky*

[Shonky*]

Also there are numerous variants of AC3 and DTS - see the wikipedia articles which whilst technical are pretty good.

[50mxe20]

Another source of information is Dolby themselves:

http://www.dolby.com/consumer/technology/tech_overview.html

[AndrewW]

the problem with threads like this is that most of your questions are asking for people's subjective opinions ... which history has shown can only lead to a ugly fight ...

[50mxe20]

And of course many of the questions have both yes and no answers!