How do I play Dolby 2.0 Surround properly?

[Xoanon]

Ive got a DTS 5.1 system and Im quite new to the whole thing. I have some Criterion DVDs which have Dolby 2.0 Surround tracks for the main movie. How do I activate the surround sound information? There is a Dolby Pro Logic button on the remote, do I turn this on? Or do I put the "super surround" option on, that turns stereo tracks into surround tracks?

Thanks for the help.

[Severity]

Depends on the kind of amp/decoder you have. Mine is setup to auto detect the audio information and then it will switch to the proper surround mode. I have my DVD player send a raw audio signal to my amp/decoder and it figuers it out. But most setups are all different. Best to consult the owners guide. Setting to super surround is ok, but it in not a true surround sound. But ti does make some stuff sound better. It's all user preference.

[Xoanon]

I have been using the Pro Logic button, it seems OK. Is this OK to use?

[Severity]

It should be. When you play a 5.1 source, do you have a 5.1 button to press? Or does it just switch on it's own?

[Xoanon]

No there is no 5.1 button, it just plays in 5.1 itself. But Dolby 2.0 Surround only comes from the front speakers and I wanna activate the encoded surround channel.

[RottenFoxBreath]

its not really a surround channel more like an echo.your better off playing the 5.1.if you get teh echo behind you,thats working.and if "super" works better leave it at that.
diolby pro logic is pretty poor compared to 5.1 and aspecially poor compared to DTS

[Xoanon]

The Criterion DVDs with 2.0 Surround dont have a 5.1 track, as this is not their original sound mix. Playing these 2.0 Surround tracks normally doesnt make the surround channel/echo come out the rear speakers.

[offline]

Dolby 2.0 is not a prologic I or surround. It is just two ac3 tracks, sometimes not even stereo. On some receivers you can activate Dolby Prologic II to simulate surround from these tracks if stereo. Prologic II
must be activated by hand (or preset)

[Xoanon]

Right, thanks for that. So what IS 2.0 Surround? E.g. Silence of the Lambs Criterion is 2.0 Stereo Surround. How does it work, if it only has 2 channels?

[offline]

Dolby 2.0 Surround (aka Dolby Prologic) is an encoder that can make a
virtual 3d effect from stereo sources. Special movie sound mixing assists the
encoder to make the surround field. For example, the frequency range
for normal speech will be directed to the center channel, thus voices are
normalized in this range when making the soundtrack.

Dolby Prologic II is superior in that it does not require any pre mixing assistance to work well and simply acts as a passive encoder (driving 6 speakers rather than the three + subwoofer of prologic I.)

[Xoanon]

Dolby 2.0 Surround (aka Dolby Prologic) is an encoder that can make a virtual 3d effect from stereo sources

Right, thats cool. How does this work though?

Dolby Prologic II is superior in that it does not require any pre mixing assistance to work well and simply acts as a passive encoder (driving 6 speakers rather than the three)

What do you mean by "passive encoder".

Sorry but I need to ask!

[offline]

What exactly do you want to do?
Try reading through http://www.dolby.com

[Xoanon]

Im just interested to know how things work.

Also, Im a low-budget filmmaker and Im wanting to put stuff onto DVD. I can do Dolby 5.1 mixes but for some of my stuff I'm only interested in a basic 2.0 surround track, and just wondered how it worked.

[Michelle]

Dolby 2.0 is not a prologic I or surround. It is just two ac3 tracks, sometimes not even stereo. On some receivers you can activate Dolby Prologic II to simulate surround from these tracks if stereo. Prologic II
must be activated by hand (or preset)

The AC3 encoder in Vegas can create a DD 2/0 audio track from a Prologic source that plays back in my receiver as a 3/1 track. So I think that Dolby Digital may have Prologic support.

[edDV]

With Dolby you need to be very specific describing which of their many technologies you are using.
http://www.dolby.com/resources/tech_library/index.cfm

Criterion will usually has some form of Dolby Pro Logic (or Pro Logic II) if Dolby Digital 5.1 is not available

The button should get you Dolby Pro Logic. My receiver can be set to automatically switch to Pro Logic when AC-3 is not available. To get DTS (when available) you need to select that in the DVD audio menus.

Here are some basic definitions:

Dolby Pro Logic is a matrix decoder that decodes the four channels of surround sound that have been encoded onto the stereo soundtracks of Dolby Surround program material such as VHS movies and TV shows. Dolby Surround is a matrix encoding process that in essence "folds" Left, Center, Right, and Surround channels onto stereo soundtracks. A Pro Logic decoder "unfolds" the four channels on playback (without a Pro Logic decoder, the encoded program plays in regular stereo).

Dolby Pro Logic II is an advanced matrix decoder that derives five-channel surround (Left, Center, Right, Left Surround, and Right Surround) from any stereo program material, whether or not it has been specifically Dolby Surround encoded. On encoded material such as movie soundtracks, the sound is more like Dolby® Digital 5.1 (see below), while on unencoded stereo material such as music CDs the effect is a wider, more involving soundfield. Among other improvements over Pro Logic, Pro Logic II provides two full-range surround channels, as opposed to Pro Logic's single, limited-bandwidth surround channel.

Dolby Digital 5.1 is a method of transmitting and storing 5.1-channel soundtracks via digital media such as DVD, digital cable, digital broadcast TV (DTV), and satellite transmissions. Unlike the Dolby Surround encode/Pro Logic decode process, which sacrifices channel separation to get surround onto any stereo soundtrack, Dolby Digital is a discrete system that keeps the multiple channels fully separated throughout the encoding and decoding processes. Dolby Digital 5.1 is the industry standard for encoding surround sound DVD movies.

DTS is a competing encoding standard to Dolby Digital. DTS supports multi-channel 5.1 encoding.
http://www.dtsonline.com/consumer/hometheatre/creating-environment.php[/b]

[yoda313]

Hello,

So I think that Dolb Digital may have Prologic support.

Yes it does. I had a prologic only receiver with my dvd player before I bought my digital amp a few years ago. Some dvds only have 5.1 tracks and those played in dolby prologic without any problem.

Dolby 2.0 is not a prologic I or surround. It is just two ac3 tracks, sometimes not even stereo

I have to disagree with that.

Dolby Digital technology can transmit mono, stereo (two-channel), or up to 5.1-channel surround sound (discrete* multichannel audio).

Virtually every DVD-Video player sold today offers a two-channel mixdown of the Dolby Digital 5.1 movie soundtrack

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

every Dolby Digital decoder also provides a Dolby Pro Logic-compatible stereo signal on its analog outputs

They can have a dolby 2.0 "SURROUND" track on the same disc. MOST dvds do. They're not dolby 4.0 because the rear speakers are MONO on a prologic track.

EXAMPLE:

Star Trek Generations (NON SE Release) - http://www.amazon.com/exec/obidos/tg/detail/-/6305181721/qid=1102882774/sr=1-3/ref=sr_...v=glance&s=dvd

Format: Color, Closed-captioned, Widescreen, Dolby

Aspect Ratio(s): 2.35:1

Audio Encoding: Dolby Digital 5.1, Dolby Digital 2.0 Surround
Rated:
Studio: Paramount Studio
DVD Release Date: May 13, 2003

I'm trying to get a ac3 identifier to show the 2.0 track indeed has dolby pro logic. I know it for a fact but I'm trying to get a program to read it so i can post a screen shot.

Kevin


(edit - I just saw eddv's post. This is more info on the same subject that I'm posting as I have seen it.

[edDV]

Here is Dolby's FAQ for Dolby Digital
It makes a good read

http://www.dolby.com/assets/pdf/tech_library/42_DDFAQ.pdf

[Xoanon]

Some dvds only have 5.1 tracks and those played in dolby prologic without any problem.

You dont play 5.1 in Pro Logic, you just let it play through your 5.1 system.

[Michelle]

The DD FAQ is quite interesting. I read one thing I don't understand. It says:

Can I hear 5.1-channel Dolby Digital programs over a regular stereo or Dolby Surround Pro Logic system?

Yes. All Dolby Digital decoders, whether 5.1-channel or two-channel, have a unique feature called “downmixing” that assures full compatibility with
any playback system.

I thought the Dolby Digital decoder was in the receiver. Where is the decoder that is doing the downmixing if you don't have a DD receiver?

[Michelle]

The FAQ answered my question later on.

Many program sources,
including DVD players and digital
cable set-top boxes, provide a
built-in two-channel Dolby Digital
decoder with analog stereo
outputs. For 5.1-
channel playback, most units
have a separate digital output
that provides the undecoded
Dolby Digital signal (data stream)
for connection to an external
unit, such as an A/V receiver, that
has its own 5.1-channel Dolby
Digital decoder.