2ch vs 6ch?

[denz_ngr]

OK I just need double clarification.... Why do DVDs have both 6ch and 2ch audio.... even if your DVD player only uses 2ch (L&R RCA cables) it can still play 6ch right?... please tell me I'm right. otherwise I have 80 gigs worth of DVDs I have to redo.

[kzPhaze]

I cannot vouch for the exact reason, but rest assured your DVD will still work in a 2 channel setup.

[Colindale]

Put 6ch into a Theater Surround sound amp, and you will know the difference!.

6 Channel is Dolby Digital or AC3.

[garryheather]

2 channel audio is sometimes used for less demanding applications, like the director's commentary. Some music titles, for example, will also maintain an uncompressed, PCM soundtrack that may be 2 channels. It does depend a lot on the disc.

All DVD players have to be able to perform a downmix on a multichannel (surround sound) to two channels - it's part of the spec.

[FulciLives]

All DVD players have to be able to perform a downmix on a multichannel (surround sound) to two channels - it's part of the spec.

In the early days many DVD videos had both a 5.1 AC-3 soundtrack as well as a 2.0 AC-3 soundtrack.

However it is true that the DVD player will downmix 5.1 AC-3 to 2 channels.

I think the reason why some DVD videos ALSO include the 2.0 channel version is that they (whomever was making the DVD) probably thought that a studio made 2.0 downmix might be (could be?) better than the DVD player doing the downmix.

However I see fewer new releases including the 2.0 AC-3 with most having nothing but a 5.1 mix because after all the DVD player will downmix it to 2 channels.

- John "FulciLives" Coleman

[garryheather]

Good point - my idea of history seems to crap out about a week last Thursday... many DVD's of older vintage, or of content of older vintage, will indeed be 2 channel. Well spotted.

A lot of dodgy, "adult" movies will be 2 channel too, not that anybody listens to the soundtrack on those much.

[Phil Thomas]

The only thing I've noticed is ....... when you play 6 ch sound in a 2ch setup, the audio level is much lower and I have to reach for the volume control.

[garryheather]

That's because the dynamic range of a DVD is very high, and the peak level must never exceed 100% - so all channels added together generally means a very low level compared with say a terrestrial broadcast or an audio CD.

HOWEVER !!

Most DVD players I've seen recently have an option in the downmix setup to "normalise" the audio, which means that it dynamically adjusts itself so that you get a more consistent, louder sounding, output. It might be worth you playing around in the setup menus and seeing what you find.

[Thunder In Paradise]

Why the heck would you want the stupid DD 2.0 Surround mix anyways? That completely destroys 1/2 the reason DVD was created, to allow for theater quality MULTI-CHANNEL 5.1 surround sound, not crappy little stereo sound. :P

[GabeB]

I believe that you can't get true 5.1 sound from 2 RCA's. You need to use either the optical or coax output of the DVD Player.

[garryheather]

Surround sound is indeed nice - but not everyone has it !

Some people can't afford it, or haven't got the space (or don't like) all the speakers. It's all about compatibility and not alienating the customer. I know one person who bought a DVD player and was miffed because he thought the coaxial out was an RF out, and he could use it on his old, knackered TV with only a tuner on it, so there you go. Classic example of legacy support...

[daredevil]

I think the question is why there is 2 and 6 channels for the same audio. For some movies the original track is in 2 channels (or even in mono) and they leave the original track for the purists, and they put a remix version for those who wants to use their supra extra home theater system

[vitualis]

As what someone else stated before... The 5.1 channel mix is often tweaked by the studio to produce the best effect on a 5.1 system. Even though it can be downmixed to just two channels on the fly, the effect would probably not be as good as a studio produced two channel track -- hence the two.

Regards.