Hi
@sfogg - Any further experience with QLI that you can share?
Sure, some of this I have written elsewhere.
On two channel music sources I am finding that I prefer the 'alternative process' mode. It is a little bit less aggressive on what it moves to the surrounds. It also uses the stage height channels more which changes the impression of the front soundstage. It seems to give more depth to the front stage. The sound/feel of the acoustic space of the music varies quite a bit between recordings which makes sense since it is really just pulling all of that out of the source. Vocals gain more depth and just sound that little bit more like they would live.
On some things it is just spooky how well it handles music and moving panned effects around all the channels. Very natural and fluid moving between all the surrounds and heights.
For example Ray Lynch "The Oh of Pleasure" is pretty amazing in QLI-32. The music starts of relatively narrow up front and as it is building the soundstage starts to widen. Then it begins to expand outward into the room and ebbs and flows back and forth using all the surrounds/heights while still feeling very very open as the extra channels are obviously not correlated between them.
I have also been noticing that there is just more detail to sounds in QLI vs stereo. I think this is due to the way the processing works and making everything stems. As it is redistributing sounds elsewhere I think it is changing how those things might have masked the original a bit. Essentially simplifying the sounds at different locations which is making it sound more detailed. It is that or the reflections/reverbs for a sound being moved and reproduced in a more correct location is adding definition to the original sound. It has been pretty obvious on any sort of resonant sound.
The 5.1 and 7.1 modes work quite a bit differently than the 2 channel mode on the QLI-32. I had read somewhere Harman demoed QLI processing using The Matrix.
Watching the I know Kung Fu scene or the lobby scene and the difference between bypass and QLI processing is dramatic.
In bypass the music in both those scenes is in L/R channels and not the center. On the MC-12 5.1 Logic 7 would steer anything common in L/R into the center as well as pull out additional surround info for the L/R channels to put into side and rears. Sort of like running 2 channel L7 on the L/R (or a 5.1 channel mix) and adding the additional outputs in with the original 5.1 signal.
QLI takes this much further. In 'Normal' mode It moves almost all of the music out of L/R and puts it into the stage height LCR channels and leaves all the sound effects in L/C/R. It is pretty incredible at how seamlessly and naturally it does this. I was unsure how hard the QLI-32 would push the screen height channels and I am very glad I went the with larger speakers for them. It also does all sort of much subtler things like using the heights for the background chimes.
No matter what I watch I have been very impressed with how QLI handles 5.1 or 7.1 movie sources. It expands the sound over the rest of the surround/height channels very well and moves effects into the height that very much make sense.
For multi-channel music sources it is a bit more of a mixed bag. When the QLI-32 is set for 5.1 or 7.1 input you pretty much have to use the alternative mode for MC music otherwise it tends to push a bunch of the music into the stage height channels instead of the LCR. The 5.1/7.1 alternative mode is more aggressive in how it positions audio than the 2 channel version. You can feed it a 2 channel source and switch between 2 or 5.1/7.1 input and hear the difference. It tends to try to widen the soundstage more in the 5.1 and 7.1 modes and move more into the surrounds and sometimes it does more than I would like.
Going from Bypass to QLI Alternative on multichannel music is more dramatic than using 5.1 Logic 7 on multichannel music and a bit more hit or miss.
With QLI processing some MC music really opens up beautifully with the extra surround channels. It just makes it sound more open and spacious and the acoustic space is more obvious.
With other surround music the QLI processing has very different results though. For example, on Baba O'Riley (Apple Music MC mix) at the start the organ is being moved all over the place in the ATMOS mix. With QLI running on top of that the organ becomes something of an echoey reverberant mess. What I think is happening is the organ is moving all over and in the mix it isn't dry, it has reverb in it. QLI is decomposing the organ and separating the reverb from the direct. So when the organ is up front it has the reverb in the rear, when the organ is in the rear the reverb is up front and same sort of things when to the sides. Basically, the organ moving all over and the reverb sort of mirroring that too. Because it is jumping around so much the reverb and the organ are all just sort of blending together into an echoey mush.
I've played other songs that have things jumping around like this without the same thing happening. In those cases I think the sound jumping around is drier without the reverb component so the QLI isn't pulling out reverb and moving it around too. so the same issue doesn't have the same thing pop up.
For other music sometimes the more aggressive remapping nature of the 5.1/7.1 modes moves too much of the soundstage into the surrounds.
Realistically, I am finding the same thing with MC music sources that I found last time I compared them against the stereo music with Logic 7 procesing. I tend to prefer the 2 channel mix with surround processing vs the MC mix. The MC mixes don't always have the same sense of space and openness. Not sure if that is due to the smaller number of surround channels or if the material in the surrounds is more correlated. When QLI works well on MC mixes it quite dramatically changes that impression but for some MC mixes it can turn into a mess as outlined above. When I ran 5.1 L7 on MC music I didn't run into those same issues as it would move anything from the surrounds into the fronts.
Based on some of the original presentations of QLI it sounds like all of this can be tuned in the 'aesthetic engine' portion of Quantum Logic Surround processing. The Lexicon QLI-32 doesn't have any sort of interface to allow this though. Or at least it doesn't have one that a mere mortal (me) has access to. I'm sure one of the original programmers could tweak settings around this by either hidden web interface pages or by logging right into the box and messing with some of the config files that it mentions in the system logs.
So, essentially… 2 channel 'alternative mode' is awesome with 2 channel music. The normal 5.1/7.1 modes are awesome with movies. With MC music the 5.1/7.1 'alternative mode' is more hit or miss depending upon how the MC music was mixed.
I have been enjoying the QLI-32 a great deal.
Very much a shame Harman didn't do more with this processing and getting it into other products while also giving more controls over the aesthetic engine.
But that's just me.
