Playing DTS 6.1 movies without a rear center speaker (1 Viewer)

[ChrisWiggles]

Good question, and something I didn't really address:

Yes, they are really the same thing. PLain DD/DTS 5.1 is the same thing pretty much. You can apply EX/ES processing to "regular" 5.1 soundtracks. Again keep in mind that "EX/ES matrix" tracks ARE 5.1.

However, the difference is that the soundtrack was not mixed and monitored expressely for EX/ES decoding, so the results, while they often should be quite good, may not always be good. For instance, you might have a hypothetical 5.1 disc with the two surrounds in mono. PLay that with Ex/ES, it will all be sent to the rear, and this certainly is an unwanted effect. So the only difference is that a disc that's labeled EX or ES *should* sound better with that processing applied, while a "regular" 5.1 mix *probably* will sound better, but you can't be sure.

It's very similar to a stereo track, versus a "pro-logic" track. Both are technically stereo, there is no inherent difference. However, the "pro-logic" track was mixed and monitored at the studio with pro-logic equipment, and designed to be played back with PL processing. The "regular" stereo mix was not, therefore your results with applying PL processing may be mixed on the regular stereo track.

The only technical difference on DVD besides the mixing methods, is that EX/ES titles can contain flags to trigger that processing automatically. Depending on your receiver/processor and options, you might have to enable EX/ES processing on regular 5.1 discs manually, while it picks up the flag and engages that processing automatically on EX/ES discs. Also, some discs are not properly flagged, or incorrectly labeled.

 

[Brad E]

Sorry about that, I should have worded that a little clearer.
My reciever does not have EX or ES. It does have DD/DTS 5.1.
My question is, if I hook up a rear channel, will I actually get any sound out of it using DD/DTS 5.1?

And if I do get sound, what then is the benefit in having reciever that actually has the EX/ES logo stamped on it?

Thanks,
Brad

 

[David Judah]

Well for one, your receiver won't have an output for the rear center. You could do a workaround EX/ES if you have an extra Pro-Logic receiver and run your rear preouts to that receiver which would prologic decode the matrixed rear channel, but results will vary depending on the phase relationship within the channels.

I tried it before I had a 6.1 receiver and while it was a novelty at first, it tended to collapse everything to the rear.

DJ

 

[ChrisWiggles]

What receiver are you talking about? I'm afraid I don't understand your question...If it can't do 6.1/7.1, then there's nothing you can hook up.

It may have an "unofficial" proprietary EX/ES processing, the marantz 5200 was an example i recall looking at. Does the same thing though, in this case you certainly good get 6th channel info, but it would not carry the logo. Certainly this capability would be listed in the specs, and there would be a corresponding output.

If not, then no you can't without more processing, which is what david suggests.

 

[Roger Dressler]

John wrote: >>Sort of have the effect of bringing the 2 rears back somewhat to mono, not that is what is happening, but that is the way it comes off to my ears in real world use of it.

The DD EX part is not near as bad as the DTS-ES part either on this for me. That is why I said go back to the DD 5.1 tracks.>I'm saying there should be no difference between the two. Nor would there be anyway.2 mixer. If that mixer has the same +/-45-deg phase shifts as the Dolby EX encoder, the added Cs component essentially reduces the effective phase shift to around 26 degrees, or about 52 degrees total across Ls/Rs. The signals are now more coherent than before. They can sound spatially different over two speakers, and a matrix decoder (like EX or ES matrix) will push them more towards the rear. If the mixing engineer tries to compensate to get the matrix decoded version to sound the same as the original EX version, then the discrete version will be negatively affected. There is no one mix via DTS ES discrete that delivers the identical performance as the original Dolby EX / DTS ES theatrical movie mix in both ES decoder cases at home. At best, one can match, but chances are that neither is identical. So, with 6.1 decoding (EX, ES matrix or discrete) you get three renditions. With 5.1 playback, you get two renditions. All may well be very similar, but not necessarily identical.

 

[Brad E]

Ok, I'm an idiot. My receiver is an H/K 7200 and I do see now that it is capable of EX processing.
Sorry about that, this is all fairly new to me but I am starting to see the light.
Thanks for the info and clearing this up.
Brad

 

[ChrisWiggles]

I think I follow your separate renditions, but to make sure: Taking aside DTS versus DD for a moment, which I assume to be the two different renditions you mention, the third would then be the ES discrete version, which would not sound the same as the original master unless you slightly affect the matrix version, in which case the matrix version wouldn't quite sound identical?

This phase shift limitation then must exist in at least one of either the matrix or discrete ES versions? But if I follow, unless the EX track is messed with as well in post-processing, it should remain the same as the original master, correct?

As always your input is great Roger, thanks!

 

[David Judah]

I assume the whole point in doing ES discrete is to minimize the deleterious effects of matrixing(making the signals more coherent, as you put it). If it did sound identical, what would be the point of having ES discrete in the first place?

DJ

 

[Roger Dressler]

Chris,

I am saying there are two versions audible with plain 5.1 playback: the matrix encoded soundtrack (EX or ES Matrix), and the discrete soundtrack (ES discrete).

If one plays these two kinds of sources using 6.1 systems, there are three possible renditions: using an EX decoder with the EX source; using an EX decoder with the ES discrete source; or using an ES Discrete decoder with the ES Discrete source.

There is no limitation caused by the phase shifters. The EX track is simply what is mixed on the dubbing stage for theatrical release.

David, yes, they sound different by design in 6.1 mode. I am simply illustrating that even in 5.1 playback, the EX and ES Discrete soundtracks may well sound different, as John S reported. His conclusion was being refuted as impossible, but I think I have shown it is not.

 

[David Judah]

Roger, in the example you gave above, wouldn't that only apply to a DTS ES matrix decoder?

If so, then going back to Kevin's original question, I still don't see why you wouldn't want to listen to the 6.1 track using a 5.1 decoder. If I'm understanding DTS's ES literature, there doesn't have to be the phase shift in the downmix like there is with both EX & ES matrix in the decoder.

Granted, you wouldn't have the "concrete" information that you would get if it was deriving a channel like the other two, but the Cs information is still there in the Ls/Rs, creating a phantom sixth channel upon decoding.

I don't see the downside. The fact that is not the same as the theatrical presentation is of little consequence in my mind. After all, DTS uses a completely different codec for Cinema & Home Theater, and even the Dolby tracks are sometimes repurposed for home viewing.

Is there something I am missing?

DJ

 

[Roger Dressler]

David,

>>Roger, in the example you gave above, wouldn't that only apply to a DTS ES matrix decoder?

 

[David Judah]

Thanks for your explanations, Roger--this isn't intuitive to most of us laymen(at least not to this one), but I am the curious sort.

I understand now there is the potential for them to not sound identical, but what I'm getting at is according to the DTS paper that Chris linked to, there is some Cs information in the Ls & Rs plus the extension data in a 6.1 ES discrete mix.

In 5.1 mode, the decoder ignores the extension bits and plays back the two surrounds as normal, but because of the extra Cs info. in those channels, according to DTS, a virtual rear center is created(I imagine it's similiar to what some 6.1 receivers do in a 5.1 configuration with their virtual 6.1 modes).

So going back to Kevin's original question, wouldn't it be better in most cases to still playback the 6.1 track in a 5.1 configuration to get some of that extra information(I'm sure it will be dependant on rear speaker placement)? Or as DTS puts it, "This creates a phantom center surround signal that is heard between the Ls and Rs speakers. Thus users with 5.1 decoders will hear all the Cs sound elements in the mix."

DJ

 

[Roger Dressler]

David wrote:

>>In 5.1 mode, the decoder ignores the extension bits and plays back the two surrounds as normal, but because of the extra Cs info. in those channels, according to DTS, a virtual rear center is created(I imagine it's similiar to what some 6.1 receivers do in a 5.1 configuration with their virtual 6.1 modes).

 

[David Judah]

I got it now. It's easy to miss some of the details when reading a press release or an article that gives a general overview of these technologies, so thanks again for taking the time to delve a little deeper.

This thread has been very informative to me and I'm sure to many others.

DJ