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AVAA C214 Redux

Reviewer: Srajan Ebaen
Financial interests: click here
Main system: Sources: Retina 5K 27" iMac (i5, 256GB SSD, 40GB RAM, Sonoma 14), 4TB external SSD with Thunderbolt 3, Audirvana Studio, Qobuz Sublime, Singxer SU-6 USB bridge, LHY Audio SW-8 & SW-6 switch, Laiv Audio Harmony and Sonnet Pasithea; Active filter: Lifesaver Audio Gradient Box 2; Power amplifiers: Kinki Studio EX-B7 monos & Gold Note monoa on subwoofer; Headamp: Kinki Studio THR-1; Phones: HifiMan Susvara, Meze 109 Pro; Loudspeakers: Qualio IQ [on loan] Cables: Kinki Studio Earth, Furutech; Power delivery: Vibex Granada/Alhambra on all source components, Vibex One 11R on amps, Furutech DPS-4.1 between wall and conditioners; Equipment rack: Artesanía Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc amp stands; Sundry accessories: Acoustic System resonators, LessLoss Firewall for loudspeakers, Furutech NCF Signal Boosters; Room: 6 x 8m with open door behind listening seat; Room treatment: 2 x PSI Audio AVAA C214 active bass traps
2nd system: Source: FiiO R7 into Soundaware D300Ref SD transport to Cen.Grand DSDAC 1.0 Deluxe; Preamp/filter: Lifesaver Audio Gradient Box 2; Amplifier: Kinki Studio EX-M7; Headamp: Cen.Grand Silver Fox Loudspeakers: MonAcoustic SuperMon Mini + Dynaudio S18 sub; Power delivery: Furutech GTO 2D NCF, Akiko Audio Corelli; Equipment rack: Hifistay Mythology Transform X-Frame [on extended loan]; Sundry accessories: Audioquest Fog Lifters; Furutech NFC Clear Lines; Room: ~3.5 x 8m
Desktop system: Source: HP Z230 work station Win10/64; USB bridge: Singxer SU-2; DAC: iFi Pro iDSD Signature; Head/speaker amp: Enleum AMP-23R; Speakers: Acelec Model One
Headphones: Final D-8000 & Sonorous X, Audeze LCD-XC, Raal-Requisite SR1a on Schiit Jotunheim R
Upstairs headfi system: FiiO R7; Headphones: Meze 109 Pro, Fiio FT3

2-channel video system: Source: Oppo BDP-105; All-in-One: Gold Note IS-1000 Deluxe; Loudspeakers: Zu Soul VI; Subwoofer: Zu Submission; Power delivery: Furutech eTP-8, Room: ~6x4m

Review component retail: €3'000/ea.

A level playing field. For reviews involving loudspeakers so practically all reviews other than headfi, our room becomes the issue. If we shun classic passive treatments for all the obvious reasons—we live where we work so can't have our digs look like a recording studio; we rent and move regularly to say no to customized absorptive installs—we have other options. We could apply room-correction DSP to linearize the frequency response but with just two speakers, still leave time-domain ringing from reflected omni bass and room modes unattended. We could exploit 'super dipole' aka cardioid so directional bass to reduce reflections with an asymmetrical dispersion pattern. We could combine that with an active electronic xover to roll out our main speakers above our two primary room modes. As a renter, a cardioid subwoofer and bass-filtered mains have been my solution for this main room. It works spectacularly well with one obvious proviso. To get visiting loaner speakers to perform equally well, I must likewise knee-cap them at 100Hz/4th-order to avoid typical omni bass from riding my 35/70Hz modes. Makers of full-range speakers of course could take justifiable offense at having them reviewed that way. After all, it's like sending out a 4×4 Jeep for review and only having it tested on inner-city tarmac when that vehicle's entire raison d'être are its off-road chops.

Appreciating the dilemma, I've had my eyes on an alternate solution that wouldn't involve rerouting low-frequency traffic to my Ripol sub. I wanted to be able to evaluate speakers as their makers intend we use them: unfiltered so full range. My recent review of the AVAA C214 active bass traps from Swiss pro-audio brand PSI Audio finally chanced upon my perfect alternate solution. Whilst its recommended so best placement in the front corners doesn't eliminate bass sidewall reflections like dipole/cardioid bass systems will, it more thoroughly eliminates pressure build-up in the front corners to undermine longitudinal and oblique standing waves. Comparing my solution to the visitors, the upshot was parity. For the first time I could hear my Qualio IQ speakers unfiltered without involving the room across its resonant bandwidth. For ultimate playback I now use the cardioid sub and active bass traps whilst slightly goosing the low-pass output of my active analog crossover to compensate Eva's loudness subtractions. But for all future speaker reviews, it'll be just the compact black Swiss traps. Their 15-160Hz absorptive bandwidth addresses the main room-mode issues and related time smear. It's why I added the above pair of AVAA C214 to my hardware inventory. It aces the job without DSP or unsightly by necessity voluminous passive absorbers. Other than my usual restrictions on size and weight, I can now accept bigger speakers for review and test them without causing room-induced bass problems. Those I find very difficult to 'tune out' despite not blaming the speakers but my space.

That playing field has just levelled. And, this pair of active bass traps will easily travel to our next residence and there work exactly the same. I can easily move them upstairs too for speaker reviews which take place there. Yousa!