Quick question: I was bored last night so I popped in a LOTR DVD. Normally I put the disk in and let it go. I have a 7.1 speaker set up with the 990/770 combo using a Pioneer AVI59. I have both optical and analog connections(SACD use).

Anyways, I was playing around with the menu selections and decided to change the audio from Dolby-Digital 5.1 to DTS-EX 6.1. Now the 990 went into "Auto DTS-Ex" and I was able to get the SB speaker icon to light up when I set the DTS mode to "discreet". The problem is I had no audio whatsoever come out of the rear speakers. Yet if I set the audio to Dolby Digital + PLL Movie, there is sound.

Am I confused or missing something here??

I haven't watched the LOTR movies in a while, so I don't recall how much content is actually included in the rear surround channel of the DTS-ES track. If there isn't much there, you could get the results you are describing, whereas DD+PLIIx will steer some back there as long as the side surrounds are reasonably active.

When I put Blade II in DTS ES discrete, I can hear the rear surround. It could just be the mix of the movie your trying. My S&V test disc also plays the ES discrete and EX signal indicators thru the rear surrounds via the 990.

In LOTR, I figured at least some of the battle scenes (action, etc) would have some sound coming out the rears on DTS-EX. With DD, it was not an issue at all. I will try another movie tonight and see if occurs there as well.

As I recall, I never got much rear channel activity on these movies either. I attributed it to the DTS mix of these discs as I do get rear channel axtivity on other DTS ES tracks.
I know the DVD publishers often tout a special home theater mix, but my impression is that the sound tracks are still basically theatrical.