It sounds like it's downmixing the center info, but it's still a guess I guess?
I have 'Under Rug Swept' on CD... I played track 9 'You owe me nothing'... and her vocals are very dominant in the center (except during the chorus where she overlays here vocals left, right, and center).
I still have no expertise to decipher how much center track information is repeated in the FL/FR tracks on a DVD-A when using the 6-channel passthru, or how much might be the 950 downmixing?
Do you see what I mean? If all DVD-A’s REPEAT track inform across the 3 front’s channels of a 6-channel recording, you will not ever have the issue except to a minor degree. What you miss from disabling your center track is repeated in the L/R so you get the info anyway. IF that is HOW all DVD-A’s are recorded.

I do know now that our ears are on the same page. Absolutely, - after disconnecting center interconnect with 950 Center/large, Optical, DPLII-C. It was gutted! When I played Track 9, on the chorus or (refrain) portion of this song ONLY (when she’s repeated in the L/R’s ) it was passable only if I bumped the dB way up.
But never in the melody itself, especially as I am not familiar with the words to this track, it was practically indecipherable what words she was singing, - she was drowned in the background instrumentals badly.
Also (as you described) retreating so far in the distance as to appear as if she had gone far away over a hill away from the staging area.

There's a 2-chan. version on that DVD-A you have right? (I hope), you should be able to do this same trick and then we should have the same reference point.
Some DVD-A’s (not all) have you access a DVD menu to engage DTS or DD versions of the disc. On ‘Under Rug Swept’ there is no choice on the DVD menu; you just insert dic and play. It’s listed on the jewel as being capable of DD or (6 channel accesable by DVD-A capable player only).

How would you say that her vocals from that test compared to the test where you take the hi-res 5.1 DVD-A track and you set the center to NONE (on your DVD-A player, not the 950) and then unplug the center chan.? (testing this you should have the analog input on the 950).
No comparison, - If you were to hear (as you must have) what I heard on the DPL-II gutting test. I would advise no way without the center. On the 6-channel/analog/no-center test there was no degradation noted anything close to the extreme loss of information when performing the DPL-II/gutted center test. The differences with center enabled/disabled in the 6-channel/analog test paled in comparison. (Remember, - on the one disc I did have to cancel the center through the Outlaw to get rid of it) (I have a new 5th DVD-A I’ll check to see if I can disable center on this one sole through the Panny) There were differences as I detailed and only on certain tracks on the two classical discs would I rate the gain as more pleasing than playing with a center. The others were fairly even although I would have to optimize my speakers to run without the center. On the ‘Under Rug Swept’ disc, given the choice (after hearing both) of running my center or not, I did feel I lost a certain fullness without the center on line, but it was nothing compared to DPLII gutted.

"(My preference). I feel having a center available just broadens your options."
I’m really thinking of HT DVD-video’s on this I just can’t imagine running ‘The Matrix’ etc. without the full compliment, (however I’m never actually TRIED it, so I guess I should, - to really know what I’m talking about). Just referring to a general thought that you probably have a few selections that would always be optimal running with a center. (Not major, just some improvement) Vs the times (when you have choice) that the mains can spread the soundstage more favorably in the way you prefer.

If the player is downmixing the center info I just shouldn't need one.
And whether its downmixing or the recorded tracks (on a DVD-A) are duplicated across the fronts. I think you will enjoy it. On mine…the Panny 91/950/Beethovens, - it can be done.
The center image I have on CD's and DVD's is razor sharp and inherently level and tonally matched to my mains (since it IS my mains). I've honestly never heard a center chan. that made a better center image or could blend as well with mains (usually 'cuz of the center's typical horizontal array design).
I think I perceive the preference for not dealing with a center much better after purchasing the new Beethoven’s, (before I might not have understood). I really was not using my 2-channel bypass on the 950 before to any great degree. (Although part of my purchase decision centered on the fact this was a 950 feature). Now with the new speakers on line, - I am listening to 2-channel ALL THE TIME. Its incredibly nice.

What 'options' do you gain other than being able to change the center's level (which I'd want to keep set at the same level as my mains)?
True,….I do use this option when the recording itself needs it. But often am too lazy to bother and just ‘accept the source’ as it is fed. I feel having the center can help 'beef' up a poorly recorded disc.(illusionary).

I didn't know you had one when I made my comments, but I still stand behind 'em.
As you should……always.

At risk of you not helping me out w/ the phantom center thing anymore
You’ll have to forgive ME, I tweak ‘people’, but never out of ‘meanness’ (I’m not that sort). I do it because I’m feeling my oats, being inexcusably silly and playful. It never scared me to go toe to toe with a guy on an arguement face to face for the sheer and simple joy of interchange. (Nasty habit, picked up from spending far too many years when I could often be the sole female amongst some pilots, ex-military types, and skydiving characters, they were ALWAYS messing with each other, and I learned to ‘join’ in, partly in self-preservation).