Thanks for giving those a listen. I find many of your observations very similar to mine. I'll add my comments/opinions below:
Yeah, that was a bit of an exaggeration, but there's no doubt it pulls it forward and elevates it in a way DSU and Auro do not.
This track demonstrates how inconsistent Neural:X can be--with the metronome it puts strong direct sound in the surrounds/heights as it does with some music--sounding similar to "all channel stereo." With other music (like this track) it does not, and some sort of garbled, distorted noise ends up there. A bit like a box of chocolates.
This song contains little ambience, so on this one (and much music like it) with Auro at the default settings, you can barely tell it's doing anything--pretty much sounds just like Stereo but with a tiny bit more "depth." I find when I crank up the strength of Auro on music like this it can do more harm than good. With little actual ambience to extract you're only increasing the volume of the generated room reflections, trying to make the music something that it's not. The only time I crank up the strength and feel it sounds appropriate/natural is music that contains a lot of ambience--something recorded in a concert hall, church, etc. With that, you still have the Auro generated sounds, but they're mixed with much louder actual ambience from the recording so it sounds more as the music was intended.
I think that cranking up the strength level may also be why you notice such a volume/bass increase. You're increasing the rolled off/generated sounds well beyond what the music will support. You may also have your sub quite a bit hotter than I run mine also.
Yup.
For stuff like this DSU does do a very good job. It can give really clean extraction for surround effects, Neural:X sometimes. Lots of Pink Floyd tracks like this as well. When music is actually intended to come from behind you I'd say DSU does it the most cleanly. This stuff is mixed like you'd mix a movie back in the 2-channel pro-logic extraction days and that's a case where I'd say DSU is the best. There's not that much of it though, no live recording will end up this way unless there are actually singers/instruments behind you.
That's the downside of the clean extraction that DSU does. It's clean, but sometimes not appropriate. Lots of music is recorded such that it will have a really wide soundstage--extending beyond the width of your speakers--but the stage is still in front of you. DSU will see that material and delete it from the front speakers and place it in the surrounds. This is why you sometimes get voices/instruments beside/behind you that shouldn't be there. It's taking the wide soundstage and wrapping it around you. Some may like that, some may not, but it's certainly not natural.
Auro also puts that stuff in the surrounds, but it leaves it in the L&R channels as well so the wide front soundstage is enhanced but not altered to a circle around you.
This can be illustrated with this track:
The "Offstage Left" and "Offstage Right" sounds are phase manipulated to make it sound as if they're coming from farther to the left and right than your speakers are placed. DSU cleanly extracts those sounds and places it beside/behind you. It sounds good and clean, but they're no longer located "Offstage L&R." If it's an old 2 channel movie and that's supposed to be action happening to your left or right, that's great. But if it's a recording of a band, the instruments on the outside edges of the band are supposed to sound like they're on the outside edges of the band, not beside/behind me in my opinion.
I really notice this on orchestral/concert hall type recordings. The sound coming from the surrounds are the enveloping ambient room reflections with Auro very close to what actually comes out of those speakers with the native immersive track. DSU and Neural:X play a lot more direct sounds from them, making it sound as if instruments are all around the room.
