For regular music CD's, I have been comparing DTS NEO:6-M to PLII-M to straight stereo in order to decide on a surround mode that sounds most like stereo, but adds a good and realistic ambiance. Initially I found DTS NEO:6-M to sound more like stereo than PLII-M. So I stuck with it. This was when I had my mains crossed over at 80 Hz. Then I crossed my mains over at 60 Hz and then finally, at 40 Hz. I decided to test the three modes all over again, and this time, I found I liked them all better, but especially, regular stereo, and PLII-M. In fact, I liked PLII-M better than NEO:6-M.

I understood that if you turn on just the surround channels and turn off the mains and the center, that DPL-IIM won't frequency shift the music to sound like something else, whereas DTS NEO:6-M does. However they do it, both PLII-M and NEO:6-M sound pretty darn good to me.

Since I set up my system with the mains crossed over at 40 Hz, a couple of other casual listeners I've had over, have also liked PLII-M better than either NEO:6-M or straight stereo. But then I invited over a friend who is a professional in the music industry who uses his ears for his living and whose ears I trust more than mine, to my surprise (!) he preferred straight stereo. DTS NEO:6-M came in second and PLII-M came in third. He said he could hear where PLII-M was cutting out the full frequency range. PLII-M sounded less full to him than straight stereo. It's part of how Dolby Pro-Logic II works, he says.

Dolby PLII is very very good, much better than Dolby Pro Logic and to people like me, it sounds fabulous. But some people who listen to music professionally, apparently can tell what is being psycho-accoustically eliminated by Dolby (even though I could not), and for people who can tell these things, straight stereo sounds better.

The other advice I got from this person in the music industry, was to always play symphonies very loud, as loud as they sound in a concert hall. Now, I realize it's not always possible or practical to do that, but he says that's the best way to hear (as close as possible) what a symphony is supposed to sound like, at home.

Now in straight stereo, when it's played loud, there is plenty of ambiance in my listening room, so maybe in a loud room, there's less reason to add ambiance via PLII and NEO-6.

I'm still experimenting, but those are my thoughts, as of now!