Dolby Pro Logic II Confusion (1 Viewer)

[Allen Marshall]

why do they even make such a thing like DPLII?

I mean if you want 5.1 sound you got Dolby Digital right, so whats the point of having DPLII which is like Dolby Digital just not as good (if i understand what DPLII is correctly)?
or like Dolby Pro Logic IIx, why dont they just make a Dolby Digital 7 or something like that or why even come up with a 7.1 or 8.1 setup if it isnt Dolby Digital or DTS?

 

[John S]

DPLII and DPLIIx are really desinged to give 2 channel DPL a step up, much closer to DD. And it really does work.

Even DLPII with EX post processing does effective 6.1 and 7.1 off of lowly Prologic sources.

I have done some recent testing using standard cable sources and LD sources. And it really works well.

This along with DTS NEO:6 are really the best reasons to upgrade past 5.1 in my opinion.

 

[Stelios]

(DPLII and DPLIIx are really desinged to give 2 channel DPL a step up, much closer to DD)

Does this mean then,that if you connect the video out of your VCR or TV will be converted to DD?

Stelios

 

[Andrew Pratt]

No it doesn't convert it to DD at least not in the sense you're thinking. All DTS:Neo and PLII are designed to do is to take a 2 channel source like VHS, CD or cable TV shows and try to more closely emulate a 5.1 discrete soundtrack from a DVD. Basically there's now better seperation in the rears and a more cohesive image across the front then what pro logic offered. Its not intended to replace or compete with a true discrete format like DD 5.1 just to help give more life to older 2.0 movies and enhance TV viewing.

 

[JamesHl]

Does this mean then,that if you connect the video out of your VCR or TV will be converted to DD?

I'm not sure I've fully decoded the meaning of your sentence (especially since video has nothing to do with dolby digital ), but you can't make an analog source give digital sound. You can't use dolby digital for everything because there is generally no dd encoding for tv (except for digital cable or satellite movie channels) and there are no regular vcrs that support dd that I'm aware of.

 

[Michael Reuben]

why dont they just make a Dolby Digital 7 or something like that or why even come up with a 7.1 or 8.1 setup if it isnt Dolby Digital or DTS?

Because a new format would render much of the existing hardware in people's homes (not to mention movie theaters) obsolete. And there's no real need for it.

M.

 

[Allen Marshall]

so pro logic isnt meant for DVD's at all?

 

[Michael Reuben]

so pro logic isnt meant for DVD's at all?

DPLII is meant for any 2-channel source. That includes DVDs.

M.

 

[ChrisWiggles]

And maybe the order of events will clear things up.

Way back when, in movie theaters, it was just stereo tracks on the film in analog. To get surround, there was no room to put in more analog tracks. So, dolby designed Dolby Surround (aka pro-logic) that would allow post processing in the theater to re-create a center, and one ambient surround channel (fed to an array on the sides/back of the theater). This was totally backward compatible, theaters could still use old stereo equipment and be fine. Or they could upgrade and get a surround decoder, that would create these extra "channels" via matrix processing.

Dolby Digital was developed, and a digital track is held between the sprockets of the film, that allows 5.1 discrete channels. This is NOT an analog track, and requires totally different equipment. The old analog tracks are still there on the film.

In the home, the difference between DD 5.1 and pro logic is huge. Pro logic is QUITE an old technology. And with allthe new powerful processors being used for DD decoding, dolby decided to implement much more modern matrix decoding that could create separate rear surrounds, and do it much better than pro logic could. So while PLII is newer than DD, it is NOT designed to be superior, and is only designed to be an upgrade to the much older Pro Logic system, to bring it up closer to what DD gives you. Any of these matrixed systems can be applied to ANY 2-channel source you want. Dolby Digital is fully discrete and very different.

Hope that explains it, dolby has good explanations on their websites as well, for instance here:

http://www.dolby.com/tech/mp.br.0102...onOfSound.html

and here:

http://www.dolby.com/tech/m.ot.0006.FilmgoerFAQ.html

You can look around more and get more info elswhere too.

I would, however, be wary about google searches, make sure you are reading from a more authoritative home theater website, not just joe smith's cool site, because there is a LOT of confusion and misinformation about the different formats, especially the '6.1/7.1' 'formats.'

 

[Steve_AS]

why do they even make such a thing like DPLII?

I mean if you want 5.1 sound you got Dolby Digital right, so whats the point of having DPLII which is like Dolby Digital just not as good (if i understand what DPLII is correctly)?
or like Dolby Pro Logic IIx, why dont they just make a Dolby Digital 7 or something like that or why even come up with a 7.1 or 8.1 setup if it isnt Dolby Digital or DTS?

In plain old Dolby Pro Logic, the surround channels are mono: that is, both surround channels output that same thing; so plain DPL is really '4 channel'. DPL II is a step up in that it synthesizes stereo output for the surround channels. DPL II (and DTS Neo and Logic 6) can take any analog or digital stereo source and synthesize 5 *different* channels. The results are quite impressive to my ears.

Dolby Digital is another thing entirely -- Dolby Digital tracks are encoded as 6 channels in the recording studio, so there's no synthesis going on in the output stage. A DD deocder requires a DD encoded digital input in order to output 6 discrete channels.

 

[Gruson]

DPL IIx is used for the original Star Wars trilogy and it's 2 channel mix.

 

[ChrisWiggles]

Herein lies some more confusion, is that DD is rightly referred to as a sound FORMAT. I think it is prudent to refer to PL, PLII, PLIIx, NEO6, etc etc as PROCESSING METHODS, rather than FORMATS. They process any 2-channel source, regardless of it's original format.

Take note, that almost all DVDs are in DD, but MANY are just 2-channel DD. On top of that you can then apply a matrix processing format (PLII, for eg) to get a matrixed surround sound. So then it is 2-channel dolby digital that is then processed with PLII to create a 5-speaker surround environment. I would also be sure to call these matrixed channels, as opposed to discrete channels.

 

[Ted Lee]

good article on dpl2

 

[Marti D.]

Thanks for the link of the review of Pro Logic II.
I just want to let those of you out there know that Pro Logic II came out in home recievers LONG before it was released to those of who mix the movies. Dolby just released a professional encoder/decoder for us to use when we mix. Nearly all the shows on TV/Film are made with an older encoder a SEU/SDU4 that is mono in the surrounds. It will be a little while before you hear in your home more Movies/shows mixed in the new Pro Logic II format.

 

[GregBe]

Hi Marti,

Could you expand on that a little. So are you saying that there will be material that will be recorded in DPLII that will give us more than we are currently getting right now.

Greg

 

[David Judah]

That's interesting, Marti. I always thought Pro-Logic II was just a better way of extracting Dolby Surround material in the decoding stage. I didn't know it was an encode/decode combo.

Thanks for the information. Hopefully, it will be put to good use soon.

DJ

 

[Steve_AS]

Just as soundtracks were mixed for Dolby Surround, soundtracks or music could be mixed with downstream DPL II decoding in mind -- so that when DPL II is applied at home, the output will be what the mixers intended.

 

[Stelios]

ChrisWiggles

Thanks a lot for your professional and simple explanation. Now I really understant the subject better. It is interesting, because I have a few DVDs that are DD 5:1 but on the Greek language the sound is only DD 2 channel. This means tha Pro Logic II will come handy.

Stelios

 

[Allen Marshall]

Chris what you said really explained well why when i pop in a movie like an anime the DD Digital bar will come up in the corner of the Reciever but PLII: Movie wont go away and say Dolby Digital like it does with movies. For some bland movies with no action and not alot of impressive things to hear i used to put it on 6ch Stereo instead of Neo 6: Cinema i just like how the samething comes out of every speaker so talking feels so centered like the person is right infront of me.........that was until i got an optical cord!

Thanks Chris

 

[Marti D.]

The new Dolby Pro Logic II Encoder/ Decoders are on these links.
go top Dolby.com and add
/tech/l.wh.0007.PLIIops.html
Dolby says"

Dolby Pro Logic II is a convenient way to deliver matrix-encoded versions of 5.1-channel mixes to consumers via a two-channel pipeline. While it isn't a replacement for the discrete 5.1-channel mix, it is a step up from the conventional Dolby Surround matrix encoding system that has been so successfully used for the last 15 years. With the proliferation of consumer decoders now being produced with built-in Dolby Pro Logic II decoders, it makes sense to move up to the latest matrix encoding technology from the leader in multichannel sound, Dolby Laboratories.

In a nutshell, Dolby Digital is always preferred since its 6 discrete audio tracks. If you want to listen to matrix encoded tracks such as a Lt/Rt which are what most VHS tapes for example are, then you would decode with Pro Logic II. Pro Logic II gives you full frequency stereo surrounds, not frequency limited (8K) mono surrounds.
You can read up more about it on the above Dolby links.
Take care,