The fourth Aperture II arrived on Thursday afternoon, and I've spent portions of the last couple of days listening with it mounted on the bedroom's rear wall as shown here:
The new Aperture replaced a 2'x4' diffusor/absorber at that location. Listening tests conducted both before and after the arrival and installation of the first three Apertures concluded that acoustic treatment of the center of the rear wall rendered the sonic presentation a tad more cohesive, more defined, "airier", and more dimensional than with that location untreated. And the "treated" configuration was in place when I posted my assessment of the impact of the Apertures installed at the center of the front wall and the first-reflection points.
So the question posed by the new Aperture boiled down to this: Would it make an appreciable difference in what I experience when listening to a given recording, especially when set against the quantum leap in perceived performance the installation of the first three Apertures had already achieved?
The short answer: It's not a quantum leap, but it strikes me as way ahead of whatever's in second place. Using the same program material listened to in evaluating the three-Aperture setup ("Modern Masters I", "Prince Igor", et. al.), I noticed--immediately, and without any tilt-or-stretch coaxing of my ears--an infusion of more palpable space into my listening room. Bass is even tauter and growlier, voice and instrument are even more finely delineated 3-D, and the "they're in the room" illusion at least a touch more spookily tactile than the gobsmacking illusion created by the three-Aperture configuration augmented by the previous (and twice the size) diffusor/absorber that occupied rear-wall center. At the same time, and as before, adding the rear-wall Aperture does not spray artficial gloss onto produced-as-flat-perspective recordings.
Happiness is...
Thanks,
Ivan, for making it possible.