DTS and Dolby Digital (1 Viewer)

[CalvinCarr]

The reciever is an old Sony 545. I don't have 5.1 outs on my current player as it is older with no progressive scan etc...I will be getting a Hi Def set later this year with a new DVD player that I want to support SACD DVDA. If I do I assune then it will have 5.1 analog outputs so my question would be if the reciver has a better bass management should I hook up both connections but use the 5.1 for SACD DVDA?

 

[ScottCHI]

yes. you must use both connections. sacd/dvd-a has to have the analog 5.1, unless you get equipment with one of several newfangled interlinks that are now available. dd/dts has to have a digital connection.

if you get a low-end player relative to your receiver, for example, you'd use the 5.1 analog outputs for sacd/dvd-a, but you'd probably want to pass your regular cds as digital (play them as dvds) to the receiver and let the receiver do the bass management and D/A conversion.

if you get a good player, you'll probably want to do all the bass management at the player, for sacd/dvd-a and regular cds, as well. then, you can pass the analog straight through the receiver, already bass-managed, in "pure" or "direct" mode even, if your receiver has this particular feature. otherwise, if you bass manage sacds/dvd-s, for example, at the receiver, then the player's D/A converters would do the first digital to analog conversion before passing the signal to the receiver, then this analog signal has to be converted back to digital by the receiver to be bass managed by the receiver, then back to analog by the receiver again before you hear it. too many conversions.

 

[CalvinCarr]

Thanks a ton.

 

[Roger Dressler]

Robert AG wrote:
>>Encoding the Dolby Digital master for theatrical release of the film is done on the mixing stage as one of the last steps in the mix. A person from Dolby comes to the mixing stage to operate the encoding equipment. And yes, you would be able to directly A/B compare the original uncompressed print master and the Dolby Digital master. The DTS master (again for theatrical release) is always done at another location and by other people.>The people who crete the sound effects, dialog and music have NOTHING to do with the Dolby Digital or DTS encoding for DVD.>BOTH Dolby Digital and DTS are significant degradations in sound quality from the original uncompressed sound elements heard on the mixing stage,

 

[Robert AG]

Feeling a bit testy there Roger? :frowning:

At any rate, as I am sure you know, the motion picture dubbing stage is an ideal venue to do a comparison between the uncompressed print master and Dolby Digital encoded copy of this source. It is the only place where you can hear the master played back on the speakers and electronics on which it was mixed. The comparison is in real time, instaneous, and with the picture running.

True, this doesn't tell the consumer much about how the DVD encoding will sound, BUT IT IS STILL A VALID AND VERY INFORMATIVE EXERCISE!!

But you know all that, I am sure.

 

[GregK]

I (think) the point Roger Dressler is trying to get across is the Dolby Digital and DTS home compression systems are both far superior to their theatrical counterparts. I don't even think a consumer Dolby Digital decoder could decode a theatrical Dolby Digital bitstream or vise versa. And the consumer DTS codec is completely different from it's theatrical version, with only thing in common being the DTS logo.

If theatrical DTS sounds better in a dubbing stage, that doesn't mean the average chain theater outlet will reveal these same differences. And again, it's VERY important to note that this certainly does not translate into how DD & DTS will compare once they are re-encoded by totally different codecs (the DD & DTS 'consumer' codecs) for DVD, HDTV, D-VHS DSS, etc....

I think it's safe to assume the original starter of this thread was inferring to quality differences between the consumer DD/DTS codecs, and not how the DD & DTS theatrical codecs compare.

 

[Roger Dressler]

Robert AG wrote:
>>the motion picture dubbing stage is an ideal venue to do a comparison between the uncompressed print master and Dolby Digital encoded copy of this source.>It is the only place where you can hear the master played back on the speakers and electronics on which it was mixed.

 

[Robert AG]

The whole argument about DD vs DTS is kind of like arguing about which of two extremely ugly women is "prettier". BOTH DTS and Dolby Digital stink as far as ultimate sound quality goes when either of them is compared to the original print master. EVEN IN THE HOME ENVIRONMENT!

>>>How so? I think it is meaningless to this discussion.

 

[Roger Dressler]

Robert AG wrote:
>>The whole argument about DD vs DTS is kind of like arguing about which of two extremely ugly women is "prettier". BOTH DTS and Dolby Digital stink as far as ultimate sound quality goes when either of them is compared to the original print master. EVEN IN THE HOME ENVIRONMENT!> >>>How so? I think it is meaningless to this discussion.

 

[Jack Briggs]

Posting at HTF requires respect for others, and when attempting to debate this topic (yet again), please do so from a position of some knowledge. Mr. Dressler here speaks with authority.

Otherwise, why can't we accept the fact that there are some DVD soundtracks which sound better than others whether they happen to be Dolby Digital or dts?

(I think this topic comes up more than any other. Please, in the future, run a search and contribute to one of the existing threads.)

 

[Robert AG]

>>>Mr. Dressler here speaks with authority.

 

[Dah-Dee]

[rant]I just don't see where RobertAG has said anything relevant to this particular thread, and I'm disappointed that he seems intent on insulting Mr. Dressler, who has been a valued contributor to HTF for quite some time. Anyone other than RobertAG feel something other than ridiculously lucky that Roger has taken an interest in discussions here and devotes his time to thoughtfully answer questions such as posed by the author of this thread? RobertAG's contemptuous statements about Mr. Dressler and his 'standing' at Dolby Laboratories speak volumes about who is truly speaking "with arrogance," seems to be "intimidated," and "is being rather immature." I'm really surprised that Mr. AG continued on the attack in such a blatant manner after Mr. Briggs gave a gentle warning in this regard. [/rant]

RobertAG, like Mr. Dressler (and others) said, seems like you are missing the point. Brad was comparing the *DVD-version* DD and DTS tracks to each other, while you are (apparently) comparing *theatrical-version* DD and DTS tracks to the theatrical master tracks you work with. Two completely different comparisons. If you'd like to compare DD to DTS, please feel free to do so -- relevant opinions of those "in the field" are always welcome by those of us who are not!

 

[Roger Dressler]

Robert AG wrote:

>>To answer his questions: I do hear direct A/B comparisons all the time in controlled circumstance. I work as a music scoring mixer in NYC.

 

[Robert AG]

The comparisons were and are done at my studio. They are comparisons of the original music masters as delivered to the dubbing stage, and the print masters from the dubbing stage to the DVD copy of the movies those masters have been mixed into. The original master elements are played back on the ProTools HD digital audio workstation I originally recorded and edited them on.

I think that comparison is about as valid as it gets, unless you care to nit pick about what interconnects or whatever I use.

What I find amusing is that I never singled out Dolby Digital as a significant degradation to sound quality - I said that BOTH Dolby Digital AND DTS significantly degraded sound quality, especially with music. Then suddenly I get attacked by Mr. Dressler - WHY?

 

[Lewis Besze]

Pitty, we might even took you seriously.....

 

[Marty Neudel]

As I read this thread, peeling off each layer of rancor, I am left with some core issues, including basic differences of what is claimed to be fact. In my experience (admittedly outside the realm of theoretical physics) facts are relatively unambiguous in nature. Most of us are unable to visit a sound stage any time we have the whim. So I am left wondering whose experiences do I accept as being valid; and who is showing off, like a noisy windbag, to the group.

One set of salient points remains clear. Roger Dressler, a well-known and highly respected professional in the field, is willing to put his reputation on the line; while Robert AG clings to the protective cover of anonymity.

Once again, I find Roger to be a creditable source of information.

Marty

 

[DanielKellmii]

I didn't mean to start any "arguments." How about we all play nice now? Hopefully, my next question won't start anything.

Yes, but are there any other ways possible to get the surround effects? For example, is there a way to get the sound of a plane flying overhead without using some sort of processing. Is it even possible to encode that much information on a film without any compression? I have noticed that music at the movies does have some degradation, but usually, it is very good.


As for keeping names private, I don't blame him. This forum is too close to his profession. Who knows, he might inadvertetly annoy some superior. In the past, I have posted to a forum that is diretly realated to my field, Aerospace, and my companies pinhead "expert" got offended that I didn't ask him first. He cc'ed my e-mail to others in he company complaining about making the company look bad by asking a question. Nothing really came of it except me getting very annoyed. Also, when signing in, it took me about 8 tries before I got something even close to my real name. I was just so happy that I have stuck with it.

 

[Robert AG]

Yes, do you people REALLY expect me or anybody else to reveal an actual name in a public forum? It is nonsense to demand that somebody publish their identity just "to taken seriously". I work freelance (as does just about everybody in my field) and do not represent a company as Mr. Dressler does. Who I am is irrevelant to the topic of this discussion, as is the names of any of the other posters.

I will however state my exact methodology for doing the comparisons I talked about so that at least you can see how I do it:

Since all sound elements are now simply computer audio files at 24 bit / 48kHz (or 47,952Hz in the case of a pull down), it is an easy matter to reproduce, store, archive and restore these files at any time for future use. This future use in my case is usually a "special edition DVD" in which scenes have been added and I need to edit the music stem to conform to the new edit.

I keep both the original music units (the as-delivered to the stage masters) and the music stem (the music element of the final 5.1 print master). Frequently, I also keep a copy of the final 5.1 print master which contains the entire sound mix.

The best material for comparison for my purposes is either the main title music or the end credit music. Both of these (especially the end credit music) are essentially unaltered in the mixdown process and are at full level with no added sound effects or dialog. All of these comparisons are regularly done in my studio.

To do the actual comparison, I:

1) Restore from backup both the original master units and the music stem.

2) Import them into a ProTools session and place them on two 5.1 tracks.

3) I can play the commercial DVD against these ProTools masters, but it is far easier and more accurate to record both the Dolby Digital and DTS tracks from the DVD into two more 5.1 ProTools tracks, aligning them in time precisely.

4) I then level match all of these elements to the original music master units. This is most easily done by inserting a polarity reversal plug-in into the element to be gain matched, and simply adjusting the volume (.1db increments in ProTools) for the best volume null. Another method is to temporarily reverse the polarity of the actual audio file. Both these methods also root out any inadvertent polarity reversals which might have taken place anywhere along the chain - these can then be corrected so all elements are in polarity.

5) The ProTools session then can be played, and any of the elements (master, stem, Dolby Digital DVD, DTS DVD) can be auditioned instaneously by using the solo buttons. Usually, I have my assistant do the switching so at least the comparison is single-blind. As I said earlier, I can simply play the DVD against the ProTools session "wild" to do the comparison, but the synchronization between the DVD and the master elements is not as tight.

The ability to do this is by no means out of the oridinary - anybody who works in film sound post production can do this same comparison very easily. The sound effects team would keep archives of the sound elements just as I keep archives of the music elements and in some cases the final print master.

I used the "visit a dubbing stage" example in my original post because this would be the one thing a consumer might be able to do if they happen to know someone who works on a dubbing stage. The Dolby Digital encoding done there for the theatrical realease, depspite what Mr. Dressler says, presents a very revealing comparison between unaltered sound elements and the Dolby Digital encoded one. Also, since representatives from Dolby are present during this process and supervise the quality of the encoding, I would think that the encoding would be performed very well unless Mr. Dressler knows something he isn't telling us about the quality of the work they do!

 

[Robert AG]

>>>Yes, but are there any other ways possible to get the surround effects? For example, is there a way to get the sound of a plane flying overhead without using some sort of processing. Is it even possible to encode that much information on a film without any compression? I have noticed that music at the movies does have some degradation, but usually, it is very good.

 

[Robert AG]

>>>So I am left wondering whose experiences do I accept as being valid; and who is showing off, like a noisy windbag, to the group.

One set of salient points remains clear. Roger Dressler, a well-known and highly respected professional in the field, is willing to put his reputation on the line; while Robert AG clings to the protective cover of anonymity.