This is with same source, same song, no matter what I am playing.
Switching between PLIIzHeight and DSX height movie mode, the DSX puts out much more bass through my front speakers, but when going to PLIIZHeight, there is much less and a thinner sound. You notice this mostly in the kick drum range.
It's very odd.
Both with Audyssey EQ engaged and dynamic volume off.
I also notice the same effect now that I think of it with the DTS6 mode, but that's also using DSX height.
I was listening to a song and switching between sound modes, and it was a moderate change in bass.
Now, when I go into the Audio quick menu on my AVR I can control the bass, treble, subwoofer, etc., In DSX adjusting the bass setting there will turn the bass down noticeably however doing the same thing in PLIIzH will show little change of bass output.
I should also mention that DSX mode has a very similar bass output compared to stereo mode, but the PLIIz is much thinner sounding than stereo.
It honestly sounds like to me, that PLIIz is passing ALL bass information to my subwoofer, but DSX mode is following a different crossover/bass redirection setting.
If your AVR has all 3 of these modes, could you try playing a 2.1 song over hdmi, then cycle between stereo, PLIIzHeight and DSX Height mode, and tell me if the bass output seems higher from the front speakers while in DSX mode compared to PLIIZHeight, then try turning off your subwoofer and doing it again.