Dolby Digital 2.0 Surround=Digital ProLogic?

Fly B

I've been told that Dolby Digital 2.0 is stereo (or mono in two channels), period.

But I've done some research recently which involves discussion of Dolby Digital 2.0 Surround. Now, is this simply the digital version of ProLogic (with matrixed channels versus DD 4.0's discrete) And would activating ProLogic on a DD decoding receiver activate the DVD's DD 2.0 Surround soundtrack (switch it from stereo)? I guess it would depend if the disc was encoded for Dolby Digital 2.0 Stereo or Dolby Digital 2.0 Surround (or both)...and would that be indicated somewhere in the packaging/on the DVD?

And...DVDs that offer Dolby ProLogic soundtracks... is this really Dolby Digital 2.0 Surround (when activated on a DD decoding receiver)?

I've got a handle on Dolby Digital 1.0 and 2.0 Mono, 4.0, 5.0, 5.1, and even 6.1 and 7.1 Surround...but this 2.0 Stereo/Surround/ProLogic thing blows my mind. Any thoughts?

lax01

Dolby Digital 2.0 is Dolby Pro Logic which is Dolby Surround. Dolby Digital 2.0 only difference is that is sent through a digital connect (whether a digital coax or toslink cable). Dolby Pro Logic and Dolby Surround are the same things, just different ways of saying them. I maybe me semi-wrong in some parts, so if anyone wants to elaborate, go right ahead.

Aaron

I could be wrong, but I think that DD 2.0 is only 2 channels. A Pro-Logic sound track on a DVD is 4.0 from my experience. I don't think you can process a 2.0 track using Pro-Logic, because the signal is digital. Pro-Logic decoding is an analog process.

Aaron

Fly B

Okay, so, I'm not the only one confused by this.

"Dolby Digital 2.0 is Dolby Pro Logic which is Dolby Surround"...but what about, for example, music DVDs that offer "stereo" as an option over 5.1? That would be Dolby Digital Stereo--2.0, yes? Or is that Dolby Digital 2.0 ProLogic, just not utilizing the center or surround channel?


"I could be wrong, but I think that DD 2.0 is only 2 channels. A Pro-Logic sound track on a DVD is 4.0 from my experience. I don't think you can process a 2.0 track using Pro-Logic, because the signal is digital. Pro-Logic decoding is an analog process. "...that was my thought, but I have just recently seen a FAQ site that claims that Dolby Digital 2.0 can carry ProLogic information, like the two channels that carry the info in Analog ProLogic.

And 4.0 would merely be "simulated" (but superior with discrete channels) ProLogic?

So much confusion....

scottvamp

I am asuming that you are using a digital reciever and digital cable. Digital 2.0 is just that 2 channel stereo. If you want (digital pro logic) then you have to set you reciever to such. If you are watching a movie with the pro logic set than you are getting a basic old school dolby surround (VHS tape) but now it is from a digital source. Most movies are DD 5.1 and that is what you want to use. There is no such thing as to 2 channel pro logic.

"I could be wrong, but I think that DD 2.0 is only 2 channels

Yes!

Pro-Logic sound track on a DVD is 4.0 from my experience. I don't think you can process a 2.0 track using Pro-Logic, because the signal is digital.

Pro logic includes the center but with option to have it phantom.
New recievers let you do many different things. They will simulate
any source in pro logic if you want. 2 channel or whatever.And that is just for starters. You have many different DSP's on any given DD reciever. Hope this helps.:eek:

lax01

I think I may have some clarifaction:

Dolby Surround 2.0 is only stereo, meaning it only has 2 Full channels of information. Your receiver then takes those two channels and process them into a front right, a center, and front left, and one mono rear channel. But in order for your receiver to do this, you must select the function on your receiver.

For example, on my Yamaha RX-V800, I can listen to CDs(2-channel stereo) with just 2 speakers (front l/r) or I could switch on the Dolby Pro Logic decoder and have the sound come from all 5 speakers. Minusing the sub because I am pretty sure that anything below 80hz is sent to the sub in DPL or 2-channel stereo.

Now there are also programs designed for Dolby Pro Logic processing. For example, some older movies on DVD are in Dolby Digital 2.0 (Dolby Surround). But in this case, unlike CDs and other non-DPL material, the DPL mix in 2.0 is designed for DPL, and is thus better represented. If you ever watch HBO or other PPV channels, most of the time the movies are presented in Dolby Surround, meaning they were designed for DPL.

Yet one more example I have:

Say you have analog cable, you feed the analog cable into an analog TV which then outputs sound to RCA interconnects (usually one red and one white). When a TV show is shown in Dolby Surround, the 2 channels come from the TV in the 2 wires which is then decoded in your receiver. Letting you have Dolby Surround.

Wow, that was probably more confusing that helping!

Stocks_sd

I ran into the same problem yesterday when I was looking at DVD's. There were two movies I wanted to buy and wasn't sure what I was getting as far as sound on one. One was dolby 2.0 stereo which I understand is just two channel stereo but the other was dolby 2.0 (surround). How can 2.0 be surround? You sure got me on that one.

Fly B

I understand ProLogic and its uses in broadcast and on VHS, and generally avoid using it when listening to stereo sources like CDs (that's a whole other thread). And I use 5.1 (DD or DTS) with DVDs whenever possible. But on occasion, a disc will not offer it. Superman II, for example, offers only "Dolby Surround Stereo"--Now, is that a matrixed digital 2.0 ProLogic, or discrete 4.0? How do you know? They don't go into numbers on the case or in the menu.

I know it's not all that important. It just seems that if a DVD is listed (as I've seen some on Amazon) with simply "Dolby Digital 2.0", it would be nice to know if that meant "Stereo" or some kind of surround. Seems we're leaning toward Surround here for 2.0, but that still leaves the question of those music DVDs with the "Stereo" option...is this DD 2.0, but not surround?

Sorry if I seem to be going around in circles, and thanks for all the input.

B

lax01

I wouldn't trust Amazon's Technical Info because they still believe that 5.1 is stereo, "Dolby Digital Stereo 5.1" (right?). I would just listen to it in DPL and it should sound alright.

johnnyamerika

I think DD Surround works like DD 6.1....basically it's 2.0, but a cabable reciever/DSP can decode the surround and center channels from it....just like the data for the rear center in DD 6.1 is encoded into the left and right surrounds, a capable reciever can pick it out. This works with other analog sources too, like certain video games, the data is sent in the RCA analog cables and decoded to the other channels by the DSP. I guess this is what you call matrix. How I've found to check it is look at the chart on the back of the disk... you see the box that shows the seperate channels as squares on the box's outline. If there are 2 mains and a center on the box, I believe it's discrete, if there are just 2 mains, it's matrixed. Basically..DPL and DPL II are DSPs, right?

scottvamp

just like the data for the rear center in DD 6.1 is encoded into the left and right surrounds

But there are also discrete 6.1 DVD's out there. But I watch all movies that are 5.1 in a matixed 6.1. Gotta love it.

if there are just 2 mains, it's matrixed.

Only if it is a mono soundtrack. Most of the time it is discrete 2 ch. stereo.:)

johnnyamerika

>But there are also discrete 6.1 DVD's out there. But I watch all movies that are 5.1 in a matixed 6.1. Gotta love it.

I know DTS has discrete 6.1, but I thought all DD 6.1 is matrixed? Just what I heard here anyway :rolleyes:

>Only if it is a mono soundtrack. Most of the time it is discrete 2 ch. stereo.

didn't know that, thanks

scottvamp

I know DTS has discrete 6.1, but I thought all DD 6.1 is matrixed?

DTS-ES is 6.1 and DD-EX is also a discrete 6.1. Just not very many out there out.:mad:

Aaron

Are there DVD's with a 4.0 soundtrack (4 discrete channels, basically discrete DPL)? I guess with a DSP you can process a 2-channel soundtrack with Pro-Logic, or more likely, the receiver does the D/A conversion and then does the Pro-Logic processing. I know I've gotten DVD's where my receiver will go into Pro-Logic mode (like Predator) and other movies where it will stay in stereo. Any ideas?

Aaron

johnnyamerika

Off the back of a DVD (Saving Private Ryan)

"Dolby Digital Surround may contain up to 4 channels of discrete encoded audio" SPR has that '3 box' logo next to it's Dolby Surround track...two mains and a surround, not center, is what it indicates. The surround channel is split into two signals by the processor, and the center is extrapolated from the two mains, by virtue of the diagram of course. SPR could be 4 channel discrete tho.

Is there any way to tell if you're listening to a digital source that's matrixed or discrete DPL?

Aaron

I think this link answers most of my questions.

http://www.polkaudio.com/home/faqad/advice.php?article=dvdlabel

Aaron

shack

Aaron - thanks for the link.

Here is a little excerpt from that article:

A Dolby Digital soundtrack can deliver anywhere from 1 (mono) to 6 (5.1 surround) channels of information. That means the DVD you just bought, the one with the "Dolby Digital" logo, may in fact be delivering full, glorious MONO! Old movies are rarely, if ever, re-mastered in any multi-channel format. Sorry pal, you're going to have to listen to that 1939 Buck Rogers movie in mono.

Does anyone know if DPLII will work with mono and if so how well?

Fly B

The link explains it well, but still doesn't totally answer the Dolby Digital 2.0 question.

From what I've gathered so far, DD 2.0 can be stereo or stereo surround (ProLogic), depending on how the disc was encoded (it could even be mono, though that seems mostly to be handled by 1.0)

I guess, if one must order from Amazon or deal with other info that simply says "Dolby Digital 2.0", without indicating Stereo, Stereo Surround, or ProLogic, you pop in the disc, turn on the DPL, and put your ear to a surround speaker and try to determine if it's been encoded that way. A fun game, but it's a shame to have to play it.

lax01

ScottVamp: Dolby does not have a discrete 6.1 or 7.1 format out at this time. They only have discrete 5.1 and matrixed 7.1, which is called Dolby Digital Surround EX. The two extra speakers are encoded in the side surrounds and is then extracted with the Dolby EX chip (?). DTS-ES can be true discrete 6.1, though many of the discs that say DTS-ES 6.1 are infact a matrix 6.1. Meaning the rear center is matrixed from the side surrounds.

scottvamp

Ya, I was thinking about the DD-EX. The DVD cases say 5.1 DD-EX which is a contradiction within itself. Either you have 6.1 or not.
In a 7 channel setup your two rear speakers are matixed together. That is why 6.1 was the way to go for me. These EX and ES is not going to do anything for ya with a 5.1 setup. All of the DTS-ES DVD's I have ARE discrete. I have to really listen to my DD-EX soundtracks and hear if I can tell or not. Here is the question that raises though

---

I do not believe that a soundtrack can actually give you a (matixed) sound , it is either discrete or it is not there at all. (5.1*6.1)Your DSP's in your reciever determine if surrounds are matixed. As for as discrete sound goes your reciever and the disc have to have 6 or more channels. But like I said I watch all movies in 6.1, matixed are discrete it is a huge improvement (IMO).:)