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John Beresford
11-19-2003, 10:01 AM
Why do DVD packages which claim the film is in "Dolby Digital 2.0 MONO" house a DVD which plays back the soundtrack, dialogue and everything from the center channel speaker only? Shouldnt the packaging then say "1.0 MONO"? Wouldn't 2.0 soundtracks be considered STEREO, and then converted into surround via Pro Logic II on a receiver?

I have a few DVDs which read "Dolby Digital 2.0 MONO" on them, yet only play from the center channel speaker. Other DVDs say "Dolby Digital 2.0 stereo surround" or some such rhetoric, and they decode in surround automatically through my receiver's Pro Logic II feature. I thought MONO meant one channel, hence 1.0?

kelsci
11-20-2003, 11:54 AM
John, your questions are good. A DPL receiver will play one or two track mono dvds over the center channel when that receiver is set in DPL mode. The receiver will do the same for a two track mono vhs hi-fi tape or laserdisc as well. I think that the DPL chip does this if it only senses one source of sound from two channels. If you wanted to hear the mono soundtrack over two speakers, then you would have to switch the receiver into stereo mode. When a soundtrack has bonifide stereo surround, the DPL chip begins to stear sounds to the other 5 speakers. I am not an expert but I think that those sounds have directional ques. In fact since I have done much experimenting with passive surround decoding, the passive decoder which has no chip essentially performs the same thing. I think the whole answer here is that in mono there is no sense of difference in sound between the two channels and in stereo surround there can be abundance of differenace between the sounds contained in the two channels. There are some active decoders that will take a mono track and synthesize it to give a surround effect. Sometimes this effect which is really a dsp is known as MONO MOVIE. I tried it on a Yamaha 2095 but did not care for it. I know that Lexicon had this feature but I never had the opportunity to hear a Lexicon unit in this mode. It is my understanding that Lexicon did this very well.

John Beresford
11-20-2003, 12:45 PM
John, your questions are good. A DPL receiver will play one or two track mono dvds over the center channel when that receiver is set in DPL mode. The receiver will do the same for a two track mono vhs hi-fi tape or laserdisc as well. I think that the DPL chip does this if it only senses one source of sound from two channels. If you wanted to hear the mono soundtrack over two speakers, then you would have to switch the receiver into stereo mode. When a soundtrack has bonifide stereo surround, the DPL chip begins to stear sounds to the other 5 speakers. I am not an expert but I think that those sounds have directional ques. In fact since I have done much experimenting with passive surround decoding, the passive decoder which has no chip essentially performs the same thing. I think the whole answer here is that in mono there is no sense of difference in sound between the two channels and in stereo surround there can be abundance of differenace between the sounds contained in the two channels. There are some active decoders that will take a mono track and synthesize it to give a surround effect. Sometimes this effect which is really a dsp is known as MONO MOVIE. I tried it on a Yamaha 2095 but did not care for it. I know that Lexicon had this feature but I never had the opportunity to hear a Lexicon unit in this mode. It is my understanding that Lexicon did this very well.

Hey Kel,

Thanks a million for responding....okay, first off so I dont get even more lost, what do you mean "only when it senses one source of sound from two channels"? How can something which has ONE source of sound--- a MONO channel---have TWO channels? And yes, that is true what you say about "forcing" the receiver into stereo if you wanna hear the mono soundtrack from two channels; that works---but sounds horrible. But I still dont get why the DVD packaging says 2.0 MONO---and yet it IS mono...shouldnt this read 1.0 mono? Where is the "2" coming from in mono speak?

With regard to what you are saying about bonafide stereo surround tracks and their decoding properly, yes, you are right----when a "Stereo Surround" VHS tape plays back through DPL II, there are directional surround effects that come through every now and then. BUT, what about DVDs that JUST READ 2.0 DOLBY STEREO? How do we know if these have surround bits encoded onto them? It says nothing of SURROUND---just DOLBY STEREO. My "Halloween II", "John Carpenter's Christine" and "Falling Down" DVDs are good examples of this....they ALL say "DOLBY DIGITAL 2.0 STEREO" or some such labeling on the back, but they ALL decode into surround through Pro Logic II on the receiver; like the receiver KNOWS there are surround bits on these stereo discs to be decoded....

kelsci
11-21-2003, 01:26 PM
John; On the FORCING THE RECEIVER INTO STEREO mode, I have never found any problems playing a mono soundtrack over the two stereo speakers regardless of whether the mono soundtrack was on two channels (DD 2.0, VHS Hi-Fi, Laserdiscs analogue or digital 2 channel mono sound). I have no explanation for you why you had poor sound response. I have also ran mono vcrs with a Y cord into the l/r audio analogue inputs of stereo receivers and amplifiers with favorable results as well.

Even though many electronic devices have two channels for recording, those two channels have the ability to hold two separate but equal mono channels, two stereo channels that may contain no ambience information for surround sound and two stereo channels that do have ambience information for surround sound.

If a mono DVD is labeled DD 2.0, this means that the mono track is on each one of the two DD tracks. If your receiver is set to Pro-Logic mode, the soundtrack will come out of the center channel. I believe the chip knows that the two tracks on the disc are perfectly in phase for center information only. There are DVDs out there that are recorded in D.D. 1.0 mono sound. The Pro-Logic chip will determine what direction it should be placed on the sound field which should be out of the center channel. What I could not tell you is if you switched that receiver into stereo mode, where would that sound come from? I do not have a mono version of a DVD to do a test of this nature.

In answer to the three movies you mention that were only listed as DOLBY STEREO, many movies were released stating at their end credits that they were recorded in DOLBY STEREO. The only way to tell whether there was in fact any sourround information on the movies was to either have a DPL active receiver or passive surround decoding circuit. Since you heard surround effects on DPL-2, I would say these films came with a surround track. Dolby's labeling of surround info on movies left one in the lurch since recorded in DOLBY STEREO featured no label indicating DOLBY SURROUND. I heard movies recorded in DOLBY STEREO that were practically monophonic in nature or featured stereo sound without any sound info for surround sound on the soundtrack. I have noticed over the years that on tv shows, DOLBY will state at the end credits DOLBY SURROUND, such as the SIMPSOMS or ENTERPRISE as an example. How really good the Dolby Surround is on these shows is another story.

John Beresford
11-21-2003, 01:42 PM
John; On the FORCING THE RECEIVER INTO STEREO mode, I have never found any problems playing a mono soundtrack over the two stereo speakers regardless of whether the mono soundtrack was on two channels (DD 2.0, VHS Hi-Fi, Laserdiscs analogue or digital 2 channel mono sound). I have no explanation for you why you had poor sound response. I have also ran mono vcrs with a Y cord into the l/r audio analogue inputs of stereo receivers and amplifiers with favorable results as well.

Even though many electronic devices have two channels for recording, those two channels have the ability to hold two separate but equal mono channels, two stereo channels that may contain no ambience information for surround sound and two stereo channels that do have ambience information for surround sound.

If a mono DVD is labeled DD 2.0, this means that the mono track is on each one of the two DD tracks. If your receiver is set to Pro-Logic mode, the soundtrack will come out of the center channel. I believe the chip knows that the two tracks on the disc are perfectly in phase for center information only. There are DVDs out there that are recorded in D.D. 1.0 mono sound. The Pro-Logic chip will determine what direction it should be placed on the sound field which should be out of the center channel. What I could not tell you is if you switched that receiver into stereo mode, where would that sound come from? I do not have a mono version of a DVD to do a test of this nature.

In answer to the three movies you mention that were only listed as DOLBY STEREO, many movies were released stating at their end credits that they were recorded in DOLBY STEREO. The only way to tell whether there was in fact any sourround information on the movies was to either have a DPL active receiver or passive surround decoding circuit. Since you heard surround effects on DPL-2, I would say these films came with a surround track. Dolby's labeling of surround info on movies left one in the lurch since recorded in DOLBY STEREO featured no label indicating DOLBY SURROUND. I heard movies recorded in DOLBY STEREO that were practically monophonic in nature or featured stereo sound without any sound info for surround sound on the soundtrack. I have noticed over the years that on tv shows, DOLBY will state at the end credits DOLBY SURROUND, such as the SIMPSOMS or ENTERPRISE as an example. How really good the Dolby Surround is on these shows is another story.

I still dont understand how a MONO DVD could have TWO TRACKS of information to be spit out of the center channel by the receiver; shouldnt TWO denote STEREO? Why label something MONO then? Doesnt MONO by itself refer to ONE source of sound, or ONE channel?

This is beginning to make me think maybe more of this has to do with car audio than meets the eye...like in my car system (and please tell me if I am way off track here or on track), I have two subwoofers which are being powered by ONE amplifier, and the amplifier is running in BRIDGED MONO mode for maximum power output to the two subs; running a car amp bridged means "combining" the two channels of a stereo amp to make one massively powerful channel, hence MONO. Is this what is SORT of going on with mono DVD soundtracks; like in other words, are two channels really being combined to make one center channel delivery? But why would a DVD studio manufacturer go through all that---why not release the film in 2.0 stereo? Why CALL something from the beginning "2.0 Dolby Digital" and then have it play back in mono?

John Beresford
11-21-2003, 01:45 PM
John; On the FORCING THE RECEIVER INTO STEREO mode, I have never found any problems playing a mono soundtrack over the two stereo speakers regardless of whether the mono soundtrack was on two channels (DD 2.0, VHS Hi-Fi, Laserdiscs analogue or digital 2 channel mono sound). I have no explanation for you why you had poor sound response. I have also ran mono vcrs with a Y cord into the l/r audio analogue inputs of stereo receivers and amplifiers with favorable results as well.

Even though many electronic devices have two channels for recording, those two channels have the ability to hold two separate but equal mono channels, two stereo channels that may contain no ambience information for surround sound and two stereo channels that do have ambience information for surround sound.

If a mono DVD is labeled DD 2.0, this means that the mono track is on each one of the two DD tracks. If your receiver is set to Pro-Logic mode, the soundtrack will come out of the center channel. I believe the chip knows that the two tracks on the disc are perfectly in phase for center information only. There are DVDs out there that are recorded in D.D. 1.0 mono sound. The Pro-Logic chip will determine what direction it should be placed on the sound field which should be out of the center channel. What I could not tell you is if you switched that receiver into stereo mode, where would that sound come from? I do not have a mono version of a DVD to do a test of this nature.

In answer to the three movies you mention that were only listed as DOLBY STEREO, many movies were released stating at their end credits that they were recorded in DOLBY STEREO. The only way to tell whether there was in fact any sourround information on the movies was to either have a DPL active receiver or passive surround decoding circuit. Since you heard surround effects on DPL-2, I would say these films came with a surround track. Dolby's labeling of surround info on movies left one in the lurch since recorded in DOLBY STEREO featured no label indicating DOLBY SURROUND. I heard movies recorded in DOLBY STEREO that were practically monophonic in nature or featured stereo sound without any sound info for surround sound on the soundtrack. I have noticed over the years that on tv shows, DOLBY will state at the end credits DOLBY SURROUND, such as the SIMPSOMS or ENTERPRISE as an example. How really good the Dolby Surround is on these shows is another story.

Kel,

Also, with regard to packaging, I have many VHS films that have the label "Hi-Fi Stereo" or "Dolby Surround" on them, which translates into the tape being read by the receiver in Pro Logic II with some ambient surround effects, which work pretty well for the most part. The "Star Trek" box set's movies in VHS Hi Fi Surround make good use of Pro Logic II.

But some 2-channel DVDs, as the ones I mentioned in my collection like "Halloween II" and "Christine" and "Falling Down" read "2.0 Dolby Digital" or "2.0 Surround" or some such rhetoric.

John Beresford
11-24-2003, 01:51 PM
Being that I cannot change a mono DVD into some kind of surround algorithm through Pro Logic II because of the DVD player's digital connection, I am thinking of something else....the other night a friend brought over a VHS copy of Martin Scorcese's "Mean Streets" and it was a HORRIBLE sounding tape; it was the ORIGINAL Warner Bros. store-bought tape, but although it said "Hi Fi" on the side of the box, the sound was crap...lots of static and a mono, disgustingly flat audio track. When popping it in the VCR and turning my receiver onto "Video 1" for the VCR connection, the tape automatically played back in Pro Logic II but only out of the center channel speaker....when I played around with the DSP modes on the receiver, I got the film to eventually come out of "TV Logic" mode, which added some dull surround effects; although very weak, TV Logic changed the mono sound into some kind of surround.

Would I be able to do the same with mono DVDs? I dont think so, because of the digital connection; I have a feeling that by trying different surround modes Im still gonna get that "NOT AVAILABLE WITH THIS SIGNAL..." message across my screen. Was I only able to do this with my VCR because its connections were analog RCAs?

kelsci
11-24-2003, 05:49 PM
John; you posted the MONO DVD question in another forum. Perhaps some of your answers will be found in that forum since I made a posting there. The TV LOGIC mode you describe may in fact be the expression equal to MONO MOVIE that I have used. It is possible that TV LOGIC may only work with analogue connections and not digital ones. If you have an unused input on the receiver, hook up a pair of audio output cable from the two channels of your DVD player to an unused analogue input on the Onkyo 600. Your manual may indicate which analogue inputs will work with TV LOGIC.

Now as to that amp in your car running the subwoofers, BRIDGING has been going on for many years in uptody,uptody home power amps and if I recall some quad int. amps of the 70s just to name a few. Accordingly, you had a few ways to use this power amp in your car so you bridged from stereo to mono to power the two subs. But lets suppose you did not bridge and each stereo amp was run seperately to each subwoofer. Sub output sound is mono, so you would have had to split one output feed into two output feeds from you car receiver's sub out( if that is what they have for a car like they have on your home theater receiver); one feed into the left amplifier input and the other feed into the right amp input. Would this give you better bass? That I cannot say. My home theater uses a separate stereo amp that is fed by a single audio output interconnect that has what is known as a Y connection. Note the letter Y has two splits at the top. One goes into the left input and the other to the right input of the power amp section of my stereo amp(a NAD 3240PE). The NAD cannot be bridged. I use two passive subs in two speaker cabinets with this amp.