What are some limitations besides sweat equity required to get it dialed in? I'd love to give it a try someday, but time is so limited...
Yeah, I cannot quite count the number of times that I felt overwhelmed dealing with the whole manual setup approach -- not so much today, though, due to experience gained. If starting from scratch, frankly, I think most people are far better off with an AVR.
If you really want to find out yourself and confirm what the downmixing/upmixing processing does, measurement testing with various test signals need to be performed. I've only ever done simple acoustic sweeps myself, but there's already enough information in there to figure out the main stuff the algorithm does.
To be succinct, overall, JRSS behaves much like Dolby Pro-logic IIx.
From a pure stereo source, L+R is summed and sent to the center channel at a lower level. The surrounds, however, receive signals from both left and right channels -- but one of them is inverted which effectively cancels out much of the centrally panned/equally left-right mixed sounds e.g. voices and bass beats. The main surrounds or side surrounds are delayed by 20ms, while the rear surrounds are delayed by 30ms. Both surround pairs do not output exactly the same identical summed signals, but sound rather different from each other. Also, notably, far more attenuation is applied to the (earlier arriving) side surrounds than to the (later arriving) rear surrounds -- with the latter providing more of the perceived "envelopment" effect than the former.
I've not determined how JRSS deals with logic steering, but it should be doing a little something on that front given how it was mentioned that it works similarly to Neural X, too. But that assumption could be wrong, I just haven't done any testing on it.
Because we know that three additional groups of speaker(s) are merely inserted/added to the mix, the easiest way to play around with manipulating the overall stereo image focus and envelopment is to vary these parameters, as explained earlier.
Below, I've now included the
center channel as an additional "adjustable" checkbox:
Larger attenuation values should be a lot more audible to make things easier for the person "dialing in" what sounds best to him/her with the specific type of material played.
Personally, I like to reduce either just the center channel; or center, side, and rear surrounds altogether with certain track/albums. For example: "Bubbles" by Yosi Horikawa is a recording that seems to employ a lot of artificially engineered phase manipulation to successfully simulate the movement of many sound objects from only left and right stereo channels. The JRSS upmixer negatively causes unwanted "busy-ness"/confusion in the original soundstage and imaging -- so
very quickly entering the keyboard combo Control+D (brings up 'DSP studio' window), a little scrolling down the PEQ section menu, and enabling the three volume reduction settings in the posted display already instantly improves the sound.
Does it sound better than the original stereo mix, though? Ah, actually, yes... I do think it's an improvement given the dryness of the acoustics in my room. In your own room, you may want more or less volume adjustments - you might possibly even prefer to mute the surrounds altogether and only attenuate the center mix.
That's not too difficult, is it?
Then again, it's not the same as Auro, Atmos, and DSU etc.!
Nah... As I've mentioned before, less options sometimes can be a boon amidst the many trivial day-to-day audiophile problems we encounter.