Mono DVD Soundtracks

[John Beresford]

Why does the packaging of some so-called "mono" DVDs read "Dolby Digital 2.0 MONO"? Wouldn't the rhetoric of "2.0" suggest a STEREO mix? Some DVDs I own claim the film is in "Dolby Digital 2.0 mono" but the entire soundtrack -- dialogue, effects and score -- all come out from the center channel, hence 1.0...someone tried to explain to me that this may happen because the receiver interprets ANY one-sourced signal as mono, even if it has two channels...my first reaction to this was "HUH?" I didn't really understand that reasoning.

From my understanding, Dolby Stereo Surround films in 2.0 decode to Pro Logic II Movie mode when played through a surround system, allowing some rear effects to decode from the film. Some of the older films in my collection have this "Dolby 2.0 Stereo" mix, including "Halloween II," "John Carpenter's Christine," "Falling Down," and "Boyz N The Hood"...all have a stereo 2 channel mix which decodes through my receiver in Pro Logic II, extracting some surround effects. But what of "Mono" DVDs? Why does my "Halloween III: Season of the Witch" DVD claim, according to Universal, that the film has a "2.0 MONO" soundtrack and yet EVERYTHING plays from the center channel?

And is there a way to get mono DVDs -- TRUE mono DVDs (like my "Amityville Horror" MGM disc) to decode into some kind of surround? When I try any DSP mode with a mono soundtrack, it reads "Not available with this signal..." across the display screen. The only mode I can run mono DVDs in is stereo, which sounds horrible...I would rather hear them from the center channel!

[joel2762]

I think 2.0 Mono would mean that the same signal is output from the left and right channels. For example if someone talked on the right side of the screen instead of being output on the right channel it would come from both. Get me? As for playing Mono in Surround...On my Sony, You put it in Normal Surround mode. It plays everything the way it was originally recorded. The reciever only knows how it was originally recorded if you use a digital cable. Would switching to Analog cables and trying a DSP mode just for that mono movie do anything? You should try it!! --Joel--

[John Beresford]

I think 2.0 Mono would mean that the same signal is output from the left and right channels. For example if someone talked on the right side of the screen instead of being output on the right channel it would come from both. Get me? As for playing Mono in Surround...On my Sony, You put it in Normal Surround mode. It plays everything the way it was originally recorded. The reciever only knows how it was originally recorded if you use a digital cable. Would switching to Analog cables and trying a DSP mode just for that mono movie do anything? You should try it!! --Joel--

Joel,

Thank you very much for your response; yet I apologize to report that in fact I do not follow what you're saying about the 2.0 mono...but with your reference to playing mono in surround, are you saying that because Im using a optical digital cable to connect my DVD player to the receiver, the receiver is going to automatically detect the mono signal and default to playing that film back in mono? OK. I can understand that, hence the reason for dropping in a mono DVD and the receiver defaulting to Pro Logic II-Movie mode and the entire DVD coming from the center channel.

But I dont think that running analog RCA cables from my DVD player into the receiver so I can mess with DSP modes every time I drop a mono DVD in the player would be realistic; but I understand your suggestion. Almost like a CD player with analog RCAs, which allows me to take 2 channel stereo music and turn it into 5.1 through Pro Logic II-Music mode, I may be able to do that through the DVD player's analog connections to the receiver for mono DVDs.

I just wondered if there was a way to do this with the DVD player connected digitally...the only DSP modes I can choose are ones which really make the sound pretty bad...normal stereo, TV Logic, Studio Mix, or maybe Orchestra...these mono DVDs sound terrible in these modes....

[joel2762]

I think 2.0 Mono might just be the same signal output from both channels but no seperation? For example, If someone is talking on the right side of the screen the voice is still output at the same level from both channels. Get me? As for playing Mono in Surround Sound. The reciever only knows what type of signal it is through a optical or coaxial cable right? What if instead of using the digital cable, use the analog cables while watching this movie instead. Then try a dsp mode, see if that will work!
-Joel-

[John Beresford]

I think 2.0 Mono might just be the same signal output from both channels but no seperation? For example, If someone is talking on the right side of the screen the voice is still output at the same level from both channels. Get me? As for playing Mono in Surround Sound. The reciever only knows what type of signal it is through a optical or coaxial cable right? What if instead of using the digital cable, use the analog cables while watching this movie instead. Then try a dsp mode, see if that will work!
-Joel-

Joel,

When you say this:

"2.0 Mono might just be the same signal output from both channels but no seperation? For example, If someone is talking on the right side of the screen the voice is still output at the same level from both channels. Get me?"

I dont understand....isn't ALL dialogue in a given movie scene originating from the CENTER channel? If someone is talking from the right side of the screen in a scene, isnt that voice usually COMING from the center channel BECAUSE it's dialogue, not score or effect? Or do I have this wrong---do voices come from left and right in soundtracks (well, off-screen voices do, but not on-screen action)? I thought everyone in an on-screen scene is heard through the center channel.

[joel2762]

Sorry for the confusion about the voice. I just mean that the same signal is played on the two channels. For example. In 5.1 Surround sound, There is a discrete channel for each speaker in the system. So Each of the 6 speakers gets it's own unique signal. Where in Mono 2.0 Both speakers get the exact same signal there is no surround mix or anything. Just pretend You have one speaker playing a mono source, and you hooked another up to that and placed them next to each other, with a few feet apart. This would be like a regular stereo setup, except both speakers are playing the same signal. No channel seperation. This is exactly what's happening on a Mono 2.0 DVD. Get it now? Sorry if it's confusing! Hope this helps!! I'll be happy to try again if you don't get it!
-Joel-

[John Beresford]

Sorry for the confusion about the voice. I just mean that the same signal is played on the two channels. For example. In 5.1 Surround sound, There is a discrete channel for each speaker in the system. So Each of the 6 speakers gets it's own unique signal. Where in Mono 2.0 Both speakers get the exact same signal there is no surround mix or anything. Just pretend You have one speaker playing a mono source, and you hooked another up to that and placed them next to each other, with a few feet apart. This would be like a regular stereo setup, except both speakers are playing the same signal. No channel seperation. This is exactly what's happening on a Mono 2.0 DVD. Get it now? Sorry if it's confusing! Hope this helps!! I'll be happy to try again if you don't get it!
-Joel-

So then why is the entire film played back through the center channel? And if this is 2.0, why cant the soundtrack decode in Pro Logic II; after all, it is 2.0, right? And in stereo, there shouldnt be channel separation, should there? Well, what I mean is, arent both speakers playing the same information, too? It's not as discrete as 5.1, is it?

[Woochifer]

No, the packaging is correct because they put the monophonic soundtrack onto the discrete L and R channels. It does not imply that it was mixed in stereo, it merely states the number of discrete tracks that got encoded into the DD soundtrack. An alternate approach would be to do a 1.0 soundtrack, and place that into the center channel. I believe that some soundtracks are done this way and labeled as such.

If everything plays through the center channel with a 2.0 mono soundtrack, then your system is playing it back exactly the way that it should. The way that the Pro Logic decoders work is that any kind of surround information that gets extracted relies on the channel separation you get with a stereo soundtrack. Same thing with the center channel, it gets extracted from the stereo signal -- sounds with no channel separation get played back through the center channel, other sounds get played through the left and right channels. If the signal is two monophonic channels, then you get no stereo separation and the decoder collapses the signal into the center channel.

P.S. This topic sounds very familiar and has been discussed many times before.

[John Beresford]

No, the packaging is correct because they put the monophonic soundtrack onto the discrete L and R channels. It does not imply that it was mixed in stereo, it merely states the number of discrete tracks that got encoded into the DD soundtrack. An alternate approach would be to do a 1.0 soundtrack, and place that into the center channel. I believe that some soundtracks are done this way and labeled as such.

If everything plays through the center channel with a 2.0 mono soundtrack, then your system is playing it back exactly the way that it should. The way that the Pro Logic decoders work is that any kind of surround information that gets extracted relies on the channel separation you get with a stereo soundtrack. Same thing with the center channel, it gets extracted from the stereo signal -- sounds with no channel separation get played back through the center channel, other sounds get played through the left and right channels. If the signal is two monophonic channels, then you get no stereo separation and the decoder collapses the signal into the center channel.

P.S. This topic sounds very familiar and has been discussed many times before.

Thank you, but I had no idea this was discussed before; forgive me and please accept my wholeheartedly emotionally tied apologies.

I just read on a DTS/Dolby Digital comparison site that 2.0 labeled mono soundtracks should play back through the two front left and right stereo speakers. So I still do not understand when you say "the system is playing it back exactly the way it should"...WHY label something as 2.0 then? Why give TWO monophonic channels when the end result is gonna be one channel mono anyway?

[joel2762]

Thank you, but I had no idea this was discussed before; forgive me and please accept my wholeheartedly emotionally tied apologies.

I just read on a DTS/Dolby Digital comparison site that 2.0 labeled mono soundtracks should play back through the two front left and right stereo speakers. So I still do not understand when you say "the system is playing it back exactly the way it should"...WHY label something as 2.0 then? Why give TWO monophonic channels when the end result is gonna be one channel mono anyway?

Labeling it 2.0 means that the same monophonic channel is playing from both of the front speakers.

[Quagmire]

John,

I understand your confussion on this matter. You would be scratching your head if you purchased an audio CD which was labelled "Mono Stereo" because these two terms mean opposite things. "DD 2.0" and "mono" seem to be opposites as well, but all that it really means is that the mono track has been recorded discretely on two channels. In theory, you could have a 5.1 mono soundtrack where each one of the channels carries the exact same information - but of course, there is no purpose in that.

If you had your DVD player connected to your receiver via the 6 channel discrete analog inputs, and you then selected that input, you would here the DD 2.0 mono tracks from your left and right front speakers instead of the center speaker. With the digital connection, your receiver is processing this two channel information using Pro Logic processing. Since the left and right tracks are identical, there is no difference betweeen them, the Pro Logic processor is sending all of that information to the center channel speaker. This is how recording engineers/mixers manipulate the signal to place dialog (and other sounds) in the center channel speaker for Pro Logic systems. Pro Logic processing extracts information which is the same in the left and right channels and sends it to the center channel speaker (L + R = C). The processing for the surround channel is just the opposite (L - R = Surrounds). Since there is no difference between the left and right channels of a DD 2.0 mono soundtrack, no information is sent to the surround speakers.

If you want to hear the DD 2.0 mono track from the left and right front speakers, you can change the audio output of your DVD player to "PCM" and set your receiver to stereo rather than Pro Logic. Hope this helps.

Q

[John Beresford]

John,

I understand your confussion on this matter. You would be scratching your head if you purchased an audio CD which was labelled "Mono Stereo" because these two terms mean opposite things. "DD 2.0" and "mono" seem to be opposites as well, but all that it really means is that the mono track has been recorded discretely on two channels. In theory, you could have a 5.1 mono soundtrack where each one of the channels carries the exact same information - but of course, there is no purpose in that.

If you had your DVD player connected to your receiver via the 6 channel discrete analog inputs, and you then selected that input, you would here the DD 2.0 mono tracks from your left and right front speakers instead of the center speaker. With the digital connection, your receiver is processing this two channel information using Pro Logic processing. Since the left and right tracks are identical, there is no difference betweeen them, the Pro Logic processor is sending all of that information to the center channel speaker. This is how recording engineers/mixers manipulate the signal to place dialog (and other sounds) in the center channel speaker for Pro Logic systems. Pro Logic processing extracts information which is the same in the left and right channels and sends it to the center channel speaker (L + R = C). The processing for the surround channel is just the opposite (L - R = Surrounds). Since there is no difference between the left and right channels of a DD 2.0 mono soundtrack, no information is sent to the surround speakers.

If you want to hear the DD 2.0 mono track from the left and right front speakers, you can change the audio output of your DVD player to "PCM" and set your receiver to stereo rather than Pro Logic. Hope this helps.

Q

Q,

I do understand to a point now, and I do understand what you are saying about the two channels being "identical" so therefore it is interpretted by the receiver as one and sends it to the center channel; to a point I understand this. Yet I still dont understand the packaging or marketing behind this---if there are two channels of audio available to begin with, why not offer the DVD in "Dolby Stereo Surround" rather than have two channels of identical audio collapse into a one channel mono experience?

And with regard to your last suggestion, it seems when playing mono soundtrack information, I CAN switch the receiver to STEREO mode without touching the DVD player's output; these mono DVDs will run in stereo mode but to me, they sound worse that way than coming from just the center channel for some reason.

[Quagmire]

John,

You said...

"Yet I still dont understand the packaging or marketing behind this---if there are two channels of audio available to begin with, why not offer the DVD in "Dolby Stereo Surround" rather than have two channels of identical audio collapse into a one channel mono experience?"

This is at the very heart of the issue... there AREN'T two channels of audio available to begin with. The original soundtrack IS a mono track. In order to change it, a remaster would have to be done. It would be great if they remastered all such tracks to at least a Dolby Stereo Surround format as you say, but in many cases they don't. The point is that they are not downgrading a stereo track to a mono track for the DVD release, they are mearly keeping the original mono track intact.

Q

[John Beresford]

John,

You said...

"Yet I still dont understand the packaging or marketing behind this---if there are two channels of audio available to begin with, why not offer the DVD in "Dolby Stereo Surround" rather than have two channels of identical audio collapse into a one channel mono experience?"

This is at the very heart of the issue... there AREN'T two channels of audio available to begin with. The original soundtrack IS a mono track. In order to change it, a remaster would have to be done. It would be great if they remastered all such tracks to at least a Dolby Stereo Surround format as you say, but in many cases they don't. The point is that they are not downgrading a stereo track to a mono track for the DVD release, they are mearly keeping the original mono track intact.

Q

Q:

So then WHY the "2.0" designation if the "original soundtrack IS a mono track" as you say....what am I not getting here? I understand there are no surround elements in the film to decode, hence why there is no "Stereo Surround Mix" or some such rhetoric to play back in PL II; but IF the film is genuine MONO, why does the packaging not say "1.0" as other mono films (like MGM's "Amityville Horror") in my collection do?

[Quagmire]

"but IF the film is genuine MONO, why does the packaging not say "1.0" as other mono films (like MGM's "Amityville Horror") in my collection do?"

Because they have placed the mono track on two discrete channels; in this case the front left and right channels. In the example you used, "Amityville Horror" they chose to place the mono track on only one channel, probably the center channel.

Think of it like this... in days of old, if you went to a movie which was presented with a mono soundtrack, that didn't mean that there was only one speaker in the auditorium. The soundtrack may have been produced through two or more speakers even though it was only a mono track. Even though the track was mono, it may have been more easily heard by the entire audience when reproduced on multiple speakers. The same rationale may have gone into the decision to place the mono track on the front two channels of the DVD rather than on just the center channel. Regardless of how many channels it is played on, the track remains mono: Like I said in an earlier post, in theory you could have a 5.1 mono soundtrack but I doubt anyone would feel that there was any logical reason to do so. At least with a 2.0 mono track, it can be heard properly by those who own only a two channel stereo system as opposed to a full surround sound system. There have been many such mono recordings over the years which were made for playback on two channel systems - the format didn't find its beginning with the advent of DVD or Dolby Digital.

Q