I was watching a movie the other night and having the option of 6.1 DTS ES Discrete I selected it as I tend to prefer DTS tracks to Dolby Digital. After a bit of listening though I noticed that it sounded a bit... flat. Specifically I wasn't noticing anything coming from the surrounds. When I went right over and checked directly I found that I was right, there wasn't any sound coming out of either the left or right surround. I checked with another disc with a 6.1 DTS ES Discrete soundtrack and had the same result.

Perhaps a bit of explanation of my setup is in order since it's a bit unusual for this day in age. Technically I have a quadraphonic system. Not for any particular reason mind you, I'm just a bit poor and after buying a new set of speakers had an old set lying around that could see a bit of use as as surrounds. There is not, however, any sub, center, or rear surrounds.

Checking the settings I found that since it's backwards compatible surround was restored when I switched the audio over to DTS, but dammit, it auto-detects as DTS ES Discrete and aside from losing a channel (or two) in the rear shouldn't it still work properly?

I found that sound was restored to surround on DTS ES when I switched the settings to state that I had rear surrounds thus causing me to believe that for some reason the reciever is choosing to cut out or downconvert to pure stereo mode when rear surrounds aren't specified.

Is this just some odd way of programming the receiver? Is there some sort of highly valid reason for this that I'm just not aware of?

I doubt there's anything wrong with your 1070, I'm sure it's just anomalies due to your setup. DTS-ES adds a sixth channel which is intended to enhance the surrounds, not take the place of them. If you're only utilizing four speakers in your system there's no reason to use ANY six or seven channel modes. Until you have a true 6 or 7 channel setup you should stick with stereo or 5 channel modes like DD, DTS, PLII, 5-stereo, etc. You should avoid using 6/7 channel modes like DD-EX, DTS-ES, PLIIx, or 7-stereo. If you play either DD-EX or DTS-ES movies and the 1070 auto-detects an EX/ES mode just switch it to regular DD or DTS and it should sound fine. You should also always have the processor set up to the actual number of speakers you're using, otherwise you won't get all of the sound from multichannel formats.

That doesn't sound like ES decoding problem but more of a speaker configuration issue. First, make sure that your surround speakers are connected to the SR and SL outputs, NOT the SBR and SBL outputs. Next, go into the Speaker Set-Up menu and make sure the Surr Back Size is set to NONE. Finally, don't forget to re-calibrate speaker levels.

Good Luck,
Sanjay

This is a semi-related question; I was under the impression that DPLIIx adds more improvements than just support for 7.1 channels, but someone mentions above that it shouldn't be used for a 5.1 system. Should I be using DPLII instead, or does it not really matter?

Yes, yes, I'm well aware that I'd be losing information by using ES rather than decoding it as standard DTS. The thing that makes this weird is that this is the only time I've had this sort of problem. The speakers are hooked up correctly (if not I would have noticed way back when I first calibrated them) and double checking with rear surrounds enabled test tones were only heard on the proper, wired speakers nothing was heard for the fake rear surrounds.

I don't think the 1070 is working incorrectly, but it's certainly odd: why is left and right surround information cut out from DTS-ES soundtracks when rear surrounds are not enabled? I would have assumed that either left and right surround information would be the same and I'd lose the rear channel information or the 1070 would detect that there was no rear channel and collapse the information into the surround channels much like it does with center channel information being collapsed to the front left and right speakers when no center is present.

AFAIK Outlaw has stated that DPLIIx auto-detects 5.1 vs. 7.1 and will matrix appropriately. Thus if you have a 7.1 system it will matrix for all 7, but if you only have a 5.1 it will only attempt to matrix for 5 speakers. This is the reason they chose it as the default processing format (my personal feelings on the issue are less complimentary as it was intended so that you're always getting sound out of all of your speakers, personally I feel that home theater is about accuracy, not gimmicking something out to more channels than it was intended for just so you can feel like you're getting your money's worth).

In short if you have a 5.1 system there is no real functional difference between using DPLII and DPLIIx. If you have a 7.1 system DPLII will only give you 5.1 channels while DPLIIx will give you 7.1

This information is stated in the "Note" box at the beginning of the "Surround Formats" section in the 1070 manual.