About a year and a half ago I moved to a new, downsized home that had a listening space whose acoustic characteristics I did not fully understand. The room is a second storey space and is roughly rectangular, with enclosed walls on one end and at the other end, balcony walls opening on to the vaulted ceiling of a living room (or lounge) space below. My thinking had been that the rectangular shape of the room would make for good hi-fi sound, with the loudspeakers placed at the enclosed-wall end of the room and facing toward the semi-open-wall end of the room. I reasoned that there wouldn’t be (and probably couldn’t be) reflection problems from back walls that weren’t there, and that sound waves passing over the rear balcony would bounce off the angled vaulted ceiling and be directed downward to be absorbed or diffused in the lounge space below. That was my operating theory, but to my chagrin, the actual acoustics of the room proved much different than expected.
While the room was blessedly free of unwanted bass resonances or obvious low-frequency standing wave problems, it exhibited midrange and upper midrange anomalies that were—how shall I put this? —challenging, to say the least. Specifically, the room seemed to have an issue with characteristic midrange and upper midrange brightness, plus the problem of tending to smear or obscure imaging and spatial cues in the music. In particular, imaging was not as precise and sound stages were not as fully formed as I felt they should have been (especially with loudspeakers whose performance I had observed in the past in different listening spaces). In short, it was as if my room was “singing along with the loudspeakers” in a discordant and acoustically unhelpful way—obviously not a good state of affairs.
Looking for solutions, I tried experiments with absorptive panels and with combination absorption/diffusion panels that I had on hand, but with only moderate success. The absorbers and so-call ‘diff-sorbers’ were beneficial, but only to a limited degree; they were acoustic bandages where a deeper and more profound kind of solution was needed. It was then that an old audio friend, Wendell Diller, head of Sales and Marketing for the loudspeaker manufacturer Magnepan, offered an observation that proved prophetic. “You know, Chris,” said Wendell, “my experience has been that in rooms where absorbers or ‘diff-sorbers’ aren’t getting the job done, there can be real benefits to using true, purpose-built diffusors. What’s nice is that most high-end audio systems seem almost infinitely tolerant of diffusors, so diffusors are an ideal, do-no-harm solution.”
It was at that moment that I recalled an encounter I had had with another old audio friend: John Bevier, National Sales Manager for the North American high-end and pro audio distribution company, Audio Plus Services. At a trade show John had demonstrated for me a then-new set of Focal Sopra-series stand-mount monitors, but what caught my eyes and ears were the distinctive diffusor panels John had placed within the room to tune up the otherwise ‘spotty’ acoustics of the hotel/demonstration room. Since the Focals were sounding better than they had any right to in an hotel space, I asked John about the diffusors, which he explained were Multifuser DC2 panels made by the Portuguese company Vicoustic (whose products are distributed in North America by Audio Plus Services).
“Listen to this,” John said as he removed the DC2 panels from the room. Immediately, the sound exhibited much more midrange and upper midrange ‘hash’, while losing imaging specificity and soundstage width and depth. “Now listen to what happens when I put the panels back,” John said with something akin to a magician’s flourish. As the panels went back in place, the sound transformed. The ‘hash’ went away, the imaging became sharply focused (almost the sonic equivalent of an auto-focus camera optimising focus for a photographic image), and sound stages became spacious once again.
Recalling that demonstration, and heeding both Wendell Diller and John Bevier’s advice, I approached Audio Plus Services about trying a set of Vicoustic Multifuser DC2 panels in my listening room. But what exactly are the Multifuser DC2 panels like? Let me provide a brief thumbnail sketch.
The Multifuser DC2 panels each measure 570 ×570 ×177mm (that is, 23.6 ×23.6 ×5.5 inches) and are made of EPS (expanded polystyrene). The panels are offered in three colours—white, grey, and black—but can also be painted to match room décor using water-based paints. The panels ship in boxes of six. Readers seeking a more upscale (albeit more expensive) and aesthetically more in line with domestic decor, solid wood solution might want to check out Vicoustic’s similar Multifuser Wood 64 diffusors.