Dolby Digital vs. 6ch. stereo

[Shake The Rug]

Ok I understand Dolby Digital and that it is true surround sound. This post is in regard to music concert dvds specifically. I understand that if I switch the setting on my receiver to 6 channel stereo that the music is being played equally through all speakers which of course defeats the purpose of Dolby Digital. However, there's no denying that playing music in 6 channel stereo surrounds the room in music much more since the rear speakers are just filler. My question is this. If I choose to play music concert dvds this way, what specifically am I "missing out on" or being denied if I don't play them in Dolby Digital? Like I said, I know that Dolby Digital spreads all the elements of the music to speakers separately and that each speaker has their own purpose.. and that playing the music equally through each speaker equally defeats this - but hey it still sounds great and fills the room more. Please don't reply with "do whatever sounds best" - I'm really curious to hear from those who can give me specifics that can tell me what not using the Dolby Digital setting for music concerts is depriving me of. Thanks!

[PeruvianSkies]

Ok, well, I am assuming that the concert DVD of choice is available in Dolby Digital 5.1, which means that all 5 speakers are active and a LFE subwoofer channel. If the concert is presented this way than it's probably mixed specifically for a concert-like feel. Somem concerts are recorded now specifically for this, while others are remixed from an older stereo mix or some other configuration, which is a slight factor in how it sounds, anyway, the point is that the concert should sound good in Dolby Digital 5.1 or DTS 5.1. However, if you choose to select 6-channel stereo you are then placing the stereo effect into all 5 speakers and a LFE channel, which will probably sound louder and perhaps fuller because all speakers are playing the 'meat' of the sound, but that doesn't necessary mean good things. A good concert DVD should enable you to feel like you are there with the surrounds picking up the ambiance created and the front three speakers covering the soundstage, but 6-channel stereo will not give you that same effect. I would recommend 6-channel playback if you have a full room of guests and you are playing a CD or music and you simply just want the sound to fill the room and there is no defined listening position. This way everyone is essentially hearing the music the same from all positions, this also works well when people place two outdoor speakers for things like pool parties, etc. Otherwise, if you were playing a concert DVD and you took your surround speakers and placed them outside the people in the pool would get lovely sounds of the crowd at the concert versus the music.

I hope this less-technical answer has helped, there are others here that will most likely provide a more thorough and technical explaination, but usually the bare-bones answer is all that is needed, so if you need more explaination just let us know.

[Woochifer]

First off, you're getting your terminology mixed up. Dolby Digital refers to the encoding/playback format, not the number of active channels. Just because something is in Dolby Digital does not mean that all six-channels (5.1) are in use. A soundtrack encoded in Dolby Digital can be 1.0, 2.0, 5.1, and any number of configurations in between. When listening to a DVD in 6-channel stereo, you're still listening to Dolby Digital if that's the soundtrack you've chosen.

The primary difference with 6-channel stereo is that you're taking two-channels and spreading that into the center and surround channels at roughly equal levels. A dedicated 5.1 track (which can be DD or DTS) uses discrete tracks for all six-channels, which means that you're getting the surround effect and imaging as originally intended by the recording engineer. With a concert DVD, this can vary considerably with some mixes placing different instruments into the surround channels or balancing them to create deliberate spatial cues, and other mixes simply recreating the front soundstage and limiting the surround channels to crowd noise and hall ambience. 6-channel stereo simply blends all of this together with no consideration for how it's supposed to sound.

As for what you might be "losing," a big part of what you "lose" anytime you go with a two-channel mixdown is the bass from the LFE track. The 6-channel stereo mode will take the original 5.1 soundtrack, and mix it down to two-channels first. The mixdown discards the bass from the LFE track and creates other problems from the outset because it simply folds down the sound from the surround channels into the L/R main channels at preset levels. For example, if a 5.1 soundtrack mixes crowd noise into the front and surround channels at equally high levels, the crowd noise can drown out the other sounds when your receiver mixes it down to two channels. In the 6-channel stereo mode, a problematic mixdown that sounded bad with two speakers will still sound bad with six speakers. If the sound is still okay in two channels, then it you might like it in 6-channel stereo.

As for what you should do. There's really no answer other than "do whatever sounds best" TO YOU. With a 5.1 mix, the recording engineer did what sounds best to them, and obviously did the mix without any consideration for how it sounds using a 6-channel stereo mode. Some people like the sound of 6-channel stereo, but just know that's not the intended playback.

[Shake The Rug]

Ok so in other words, if the dvd offers 5.1 DD and I select that to use - but I choose to listen to it in 6 channel stereo, it's still DD even though it doesn't say that on my receiver's display?

[PeruvianSkies]

Thanks Wooch for saying pretty much what I said.

[emorphien]

Ok so in other words, if the dvd offers 5.1 DD and I select that to use - but I choose to listen to it in 6 channel stereo, it's still DD even though it doesn't say that on my receiver's display?
Basically. The audio on the DVD is encoded in a certain way. Your receiver can either reproduce it as encoded, or you can force it to present it in a different way, but the audio coming from the DVD is still the same.

I personally don't generally care to do that, if it's produced a certain way I usually play it back that way. Playing a DD source in all channel stereo which was originally mixed to use all 5 of my speakers differently loses some of the ambiance and separation of voices in my experience.

[Woochifer]

Thanks Wooch for saying pretty much what I said.

And thank you Mr. XXX (http://forums.audioreview.com/showpost.php?p=178068&postcount=10) / Dollar Theater Afficionado (http://forums.audioreview.com/showpost.php?p=178408&postcount=14) for taking the time to replying to 25% of my post! :cornut:

[Wireworm5]

Although the above explainations are good I would argue that the majority of concert dvd's that are encoded to 5.1 DD are still recorded in stereo format. And thus sounds better in 6 channel mode because it actually 2.1. If you switch to 2 channel pcm you loose this LFE affect even though it still directing bass freq. to the sub.
Dolby soundfields sounds muddy to me in comparison to 6 ch but I concede I may not have my speakers parameters settings optimized for Dolby.

[PeruvianSkies]

No problemo...If I can say 25% as much and still communicate nearly the same thing than that only shows that you use alot of 'filler' which is no suprise since most of your posts are like reading the encylopedia, only not nearly as accurate.

[Rock789]

6ch sterio is good for having parties
dd or dts is good for watching movies
2ch or 3ch is good for a front soundstage

[Woochifer]

No problemo...If I can say 25% as much and still communicate nearly the same thing than that only shows that you use alot of 'filler' which is no suprise since most of your posts are like reading the encylopedia, only not nearly as accurate.

Wow! Must be a new era on this board ... did I hear you talking about accuracy? Don't tell me! The "accuracy" from those XXX (http://forums.audioreview.com/showpost.php?p=178068&postcount=10) and Dollar (http://forums.audioreview.com/showpost.php?p=178408&postcount=14) theaters that you frequent inspired you to start fact checking before posting! Many congrats are in order if that's the case! :thumbsup:

[PeruvianSkies]

Wooch don't be upset because I would rather go to a budget theater than sit in your home theater and watch the 'neverending dvd collection'.

[Woochifer]

Wooch don't be upset because I would rather go to a budget theater than sit in your home theater and watch the 'neverending dvd collection'.

Quite the contrary. Last thing I need is to clean up after someone who professes expertise in and preference for XXX and Dollar theaters! It's like who knows what the Peruvian Real Genius has stepped in or sat on! :lol:

[PeruvianSkies]

I don't claim to be an expert in anything, unlike you who writes endless amounts of information and believe that you are correct in everything....like our discussion on D-VHS.
Anyway, how's your neck these days looking down at that TV sitting a few inches from the floor or are you just a midgit?

[westcott]

I hope this less-technical answer has helped, there are others here that will most likely provide a more thorough and technical explaination, but usually the bare-bones answer is all that is needed, so if you need more explaination just let us know.

Ditto. Well said.

Dolby Digital implies discrete information sent to each channel. 5 channel audio is not. All the audio information is sent to all channels equally (unless bass managment steps in).