Room Treatment Reviews

My initial complement of Curve System models comprised two Medium Absorbers ($299.99 each) placed at the first-reflection points of my sidewalls, two Medium Diffusors ($349.95) at the second-reflection points, a Corner Trap ($574.90) at each end of the front wall, two Small Diffusors ($274.95) on the sidewalls even with my listening seat, a Medium Absorber hung on my front wall in front of my glass patio door, and a Large Diffusor ($399.95) hung behind my listening position—all in all, $3699.52 worth of Curve System. I listened with this configuration for a few weeks, to let my ears grow accustomed to it. With any new addition to my system, I find it best to set it up and live with it for a while before getting too judgmental.

That first configuration certainly improved my room's sound. I heard a little less bass overhang, and felt I could hear more of each recording's own sonic signature and less of my room's—each recording sounded a bit more distinct from every other recording. Thankfully, the Curve System in no way made my room sound lifeless or dead. It still sounded like my room, just better. At this point I took some measurements using John Atkinson's calibrated Mighty Mike II and Holm Acoustics' Holm Impulse program. JA will report in a future issue what the measurements reveal.

Curve Ball
After I'd lived with the Curve System for about a month, John Calder called, wanting to give my treated room a listen. I invited him over one afternoon and we listened to some tunes. At one point, I got the hankering to play for him one of the choral CDs I'd produced for Cantus and that JA had engineered. I left the music playing as I searched for the right disc, my back to the listening area. All of a sudden, I was aware that the sound of my system had drastically changed.

"What did you do? This sounds way better!"

"I switched the Absorbers' and the Diffusors' positions," he said.

Indeed, now the Diffusors were diffusing the first sidewall reflections and the Absorbers were absorbing the second reflections. I found the difference astounding. The tonal balance was completely unaffected by the flip-flop of the panels, but the soundstage was much more clearly defined, with greater separation of instruments yet with a more cohesive spread from left to right. Soundstage depth was also noticeably better, with great front-to-back layering of sounds. Most important, I felt I had to concentrate less to follow the music and let my stereo fool me into believing a live event was occurring. It was one of the more shocking moments of my audiophile life.

I had initially positioned the Curve panels according to conventional wisdom, to absorb the first reflections. But clearly, in my room, diffusing the first reflections gave me a far more rewarding sound. Calder himself believes in diffusing the first reflections, diffusing the walls and ceiling at the 90¯ points, straight across from my ears, and then absorbing subsequent reflections. Removing the Diffusors from the first-reflection points, or replacing them with Absorbers (either the Curve Absorbers or my own Echo Busters) diminished the realism of the stereo image in a major way. I never would have thought diffusing the first reflections would be so important, but in my room the results were clear, predictable, and, dare I say it, magical.

In the weeks after Calder's adjustments of the panels, I really began to get a handle on how to dial in the Curve System to my room. Ultimately, I found that the Large Diffusor really didn't work there—I preferred the sound of my system without it. I liked the area behind my listening position to sound more live than dead, the live sound immersing me more deeply in the music. I also discovered that the precise placement of the Diffusors made a difference in my system's soundstaging. Using a full-length mirror, I dialed the Diffusors into place so that the first reflections hit each Diffusor's curve just past the apogee of the arc, closer to my listening seat. These proved to be the optimal positions, giving me the widest soundstage and greatest overall clarity.

Later in my time with the Curve System, I had Calder swap out two Medium Absorbers for two more Medium Diffusors. I then stacked the Diffusors two high at the first-reflection point, which gave me even better soundstaging. Around this time I also borrowed, from an audio buddy of mine, a few absorbing panels made of fiberglass by Ready Acoustics. I set two of these up at the second-reflection points and two more in front of the Curve Corner Traps, with the Small Diffusors flanking my listening chair. This configuration produced the best sound I've had in my room. The added absorption from the Ready Acoustics panels tightened up the bass without overdamping the room, while the Curves were still able to work their magic in clarity and soundstaging. I was able to have my sweet corn and eat it, too.

Diffusion
Summer has gone, the sweet-corn stands have been packed up for the winter, and I've moved from my home in Minnesota to Portland, Oregon, to conduct some fabulous choirs and continue my graduate education as a choral conductor. I have to admit that, right now, my life as an audiophile feels a bit diffuse. I miss my old listening room, especially how it sounded with the Acoustic Geometry Curve System completely dialed in. Not only have I had to say goodbye to my home and listening room, but, more important, to all of my friends and family. My wife and I are having a great time in Portland, but we miss the people we love in the Midwest. As I write this review, I especially miss my audio buddies, who would come over, drink beer, geek out over tubes and cables, and sing "Islands in the Stream" and "Mr. Roboto" with me until 2am. They made this hobby fun for me, and I hope I made it fun for them. Thanks, Chris, Kurt, and Chris. My new listening room in Portland is a dedicated studio space that should sound great, but I wonder if it will ever feel as sweet as my old room in Minnesota. I've come to the conclusion that listening rooms sound only as good as the memories created in them.

The Acoustic Geometry Curve System is a relatively novel and inexpensive approach to room treatment. The attractive shapes of the various models, and the flexibility of fabric choices, should make for a nice visual addition to any listening room. The absorptive qualities of their cotton and vinyl will damp and tame some unwanted liveliness, and their method of diffusion deserves to be heard. I was most impressed with the Curve System's ability to treat my room without robbing the music's life.

I have one caveat: If your room requires more absorption than mine did, especially in the bass, you may need to augment the Curve System with some more traditional, fiberglass-based absorbers. If, like most audiophiles, you have money and/or space enough for only two panels of acoustic treatment, I highly recommend you try diffusing your first reflections with the Curve Diffusors—their effects in my system became addictive, and added to my enjoyment of listening in ways I could not have predicted.