Skimmed the article... eh, I don't really think that theoretically deep about it. So I'll leave that to others.
All I can say is that I use
both -- summed and mono.
The ff. is just an overview sample of how I went about with my
manual bass managed EQ corrections in one of my setups.
Presuming one is already done with the level & distance setting, crossover settings, as well as aligning speakers and sub, one may find oneself with the ff. summed L+R response measured at the MLP:
Since there is only one sub in this bass managed configuration, we can apply EQ to that driver first:
output stage or after crossovers are applied (PEQ set 2 -- similar to miniDSP, JRiver can arrange and group one's set of correction filters in a certain order)
Placement and room acoustics situation between the left and
rear right speakers
(rears too) is not 100% symmetrical so I EQ each
separately (ideal) in the bass area (as well as measure in SUM afterwards -- one may need to make EQ adjustments in sum or using shared PEQs):
(input stage or before crossovers are applied)
High above the transition zone, we can apply shared EQ correction for both.
Same is true for the rear channels in this 4.1 mch setup:
(input stage or before crossovers)
Single point measurements for each speaker are done as well as summed (L+R and fronts+rears) sweeps... but summing is much easier to do if you use the moving microphone method (MMM).
The LSR 305s (rears) HF response is already pretty flat on- and off-axis so there's not much to correct. The Sceptre S8 (coaxial main fronts), while having good beamwidth and directivity control isn't as straightforwardly "flat" or smooth and so requires a bit more care to EQ all the way up there.
Several measurements were necessary, both nearfield, at the main listening position, and everywhere in between! LOL I have more than one seating position (and I like to move around),
so adjustments have to made along the way even if one can easily get a perfectly flat response right at the MLP.
With bass frequencies, I use Var smoothing. However, I prefer to use psychoacoustic smoothing above 1kHz first, then maybe 1/24 etc. only afterwards or at later stages.
Then I verify that my EQ adjustments are "relatively good" in as many ways as possible...
I recently re-did my EQ in that quite precarious, "
speaker dominated" region... so might as well post some of the results from my adjustments here.
Very near-field (30cm) from speaker horn-throat log sweep; and separate MMM RTA+peak measurements (about half a meter away)
Correction works
equally well for
both left & right speakers
MMM right in front of MLP at 1.5m distance (straight on-axis)
At actual MLP 2m distance which is 15 degrees off-axis (exaggerated toe-in is applied)
Purple and blue are corrected responses
How does my EQ affect the
off-axis response well beyond 15 degrees?
Looks like an improvement.
My vertical measurements below may not be so accurate, and I was getting tired so I stopped at 15 degrees...
We also see improvements here, too.
And finally, for the
big picture (or summed response at
all seating areas):
In this particular exercise, the sub channel was relatively easy to EQ as a single unit. BUT, the bass area around the transition zone was a little more difficult to balance across all couch seating areas and across all speakers -- hell, I don't always like to sit at the exact center sweet spot. The mids around the transition area, on the other hand, I decided best not to touch.
Lastly, even though I used a lot of PEQ bands (10) in the upper frequencies on my S8 main monitors, I 'corrected' or 'improved' just enough, and
listened to esp. female spoken word audio tracks and music vocals to verify that the improvements were real as heard and not just imagined visually -- among a bunch of other test tracks. Having presets to quickly cycle between EQ settings while in the middle of playing test tracks helps tremendously here. I also deliberately tried to limit my use of high Q or narrow bandwidth filters. BTW, I didn't exactly apply every correction filter generated by REW -- manual adjustments and averaging were done and I didn't try to force-fit the FR to a given target specifically.
Above is an overlay of the 'averaged' Harman Target made by
@thewas_ . It doesn't really fit precisely even with psychoacoustic smoothing in place, and that's totally fine! Ideally, one should not EQ by sight alone. One should also listen and make EQ adjustments by ear. In this setup, smooth and clear mids were my main priority as I do not use a center channel -- and this setup is primarily for movie watching. And while I can live with a little less upper bass, I felt that I needed more boost in the infrasonic region for those blockbuster movies and epic soundtracks, so I will be keeping it right there...
P.S. BTW, for my desk setup, my EQ settings are linked to as one i.e. it's all in mono. Measurements achieved there are way flatter and more symmetrical so it's perfectly okay.