Recommended Components

Acoustic Geometry Small Curve: $399.99 ★
Medium Curve: $449.99 ★
Deluxe Curve, Walnut Frame: $549.99 ★
Deluxe Curve, Red Oak, Stained Black Frame: $549.99 ★
Acoustic Geometry's Curve System comprises Diffusors, Absorbers, and Corner Traps, each 42" high and available in a number of fabric choices. Each model is built on a wooden frame with a wedge-shaped cleat for hanging the product from a matching piece attached to the wall. Diffusors include a Mass-Loaded-Vinyl (MLV) membrane and are intended to control low- and midbass frequencies; Absorbers are essentially the same design as the Diffusors, but have an acoustically transparent front and don't include the MLV membrane; Corner Traps are triangular wooden frames filled with recycled cotton. In EL's listening room, the Curve System created a wider soundstage and greater clarity. Diffusors: $339.98$639.98, depending on width. Absorbers: $320.98$395.98, depending on width. Corner Traps: $697.98. Prices based on Guilford fr701, Anchorage and Acoustic Suede. All other sizes and fabric options quoted on individual basis. (Vol.35 No.2 WWW)

ASC StudioTrap: $589 ★
Adjustable tripod-mounted room-tuning device that represents the "latest in TrapThink from ASC," according to J-10, who uses an array of StudioTraps to great effect in his Manhattan loft. The front half is treble-reflective for a brighter sound, while the back side is treble-absorptive for a drier acoustic. He highly recommended the Traps for "anyone whose family will allow them to populate the listening room with gobos." (Gobos are "sound-absorbing panels used to surround performers in recording studios.") Stereophile's "Accessory of 1999." (Vol.21 No.12 WWW)

ASC SubTrap: $659-$839 ★
This "big, chunky black box" sits under a subwoofer to attack acoustic problems caused by the interactions of a subwoofer's output and the room's modes. Improvements in room acoustics were immediate, thought KR, even with the subwoofer disconnected: "There was less apparent energy from clapping, loud conversation, or just stomping around." With the system turned on, there was "less apparent bass energy from all wide range signals." With a Paradigm Servo-15 sub sitting atop a SubTrap, bass was deeper and more detailed: "Ah, yes—glorious bass without the boom!" Available in three sizes: 15", 18", and the 22" square model reviewed. (Vol.27 No.9 WWW)

ASC TowerTrap: $411-$1096 ★
Originally called the Cube Tower, the TowerTrap is a "smaller, more cosmetically acceptable, more affordable version of the classic TubeTrap," writes BJR. "Very effective at taming mid- and upper-bass room anomalies. Looks like an attractive Vandersteen speaker sitting there in the corner." (NR)

ASC TubeTraps: $459-$1046 ★
Relatively inexpensive but remarkably effective room-acoustics treatment. TubeTraps soak up low-to-high bass standing-wave resonances like sponges. WP agrees, using Traps to optimize the acoustics of his room for MartinLogan SL3 electrostatics, while BD used them to optimize his room while auditioning the Thiel CS7.2s. Using the Music Articulation Test Tone (MATT) from Stereophile's Test CD 2 (STPH004-2), he first positioned them for smoothest overall response and articulation, then "dialed-in depth, dimensionality, and ambience." A chart recorder graphically showed the changes. In the end, "The sound was fantastic," quoth BD, who recommends them unconditionally. (Vol.9 No.3, Vol.15 No.2, Vol.16 No.12, Vol.19 No.1, Vol.20 No.5, Vol.23 No.2 WWW)

Auralex SubDude II: $70.99 ★
An MDF platform 23" long × 15" wide, covered with a carpet of thick felt and supported by two risers of high-density isolation pad, the SubDude has a rated load capacity of 300lb. KR found that the SubDude significantly isolated his Paradigm Servo-15 subwoofer from the live wooden floor and made the sound "tighter and fuller, but, conversely, less obtrusive." When used under full-range speakers, the SubDudes offered similar bass results while affecting high-frequency performance. Current SubDude II has a lower profile than the original sample reviewed. (Vol.27 No.12 WWW)

Bag End E-Trap: $1760 ★
Uses active electronics to control an acoustic device that acts directly on room acoustics rather than imposing anything on the electronic signal path. With its 10" driver, controls, and power amplifier in a box measuring 18" H × 13" W × 9.5" D, the E-Trap looks like a small subwoofer without input terminals. "While the appearance of the E-Trap is generally not noted, its effect on room acoustics is substantial," praised KR. It canceled out the superimposition of room modes, providing tight, clean bass while reducing the effects of ambient noise. (Vol.31 No.7 WWW)

DHDI ZR Micro Twin Mk3: $888 ★
ZR Sample Rate 8 Bit Mk3: $387 ★
Delta H Design, Inc., or DHDI, is an acoustics and architecture firm in Los Angeles County that manufactures room-treatment products for the professional and domestic markets. Two of the latter are from DHDI's Zero Reflection line: the ZR Micro Micro Twin, which measures 24" × 48" x 1.25" and is covered with fabric, is intended for placement directly behind one's speakers, while the curiously and clunkily named ZR Sample Rate 8 Bit ($383) is a 20" × 40" × 0.75" sheet of MDF into which has been CNC-carved an intricate pattern of ridges. After treating his room with two ZR Micros and three ZR Sample Rate 8 Bits, JM noted an appreciable improvement in sound: "I loved it. Indeed, I was taken aback at how much of an improvement I heard." (Vol.38 No.4 WWW)

PSI AVAA C20 electronic bass trap: $2769 each ★
In a field dominated by DSP products, the AVAA C20 stands out: this response-correction device uses pure analog technology. Inside the AVAA C20—its name stands for Active Velocity Acoustic Absorber—is a microphone, a perforated membrane, a velocity transducer, and an amplifier with feedforward and feedback. In principle, the C20 converts incoming pressure waves into velocity waves, thus absorbing them. It is said to work on pressure waves between 15 and 150Hz without affecting other frequencies—and more than one C20 can be used in a given room. In a guest review for Stereophile, acclaimed mastering engineer Bob Katz described the AVAA effect as more of polishing than "fixing" per se and praised the active C20 for working well in tandem with his more traditional (and sizable) passive trapping products. (Vol.39 No.6 WWW)

Ready Acoustics Chameleon Super Sub Bass Traps: $309.99 ★
The Chameleon Super Sub Bass Trap measures 48" high × 24" wide × 6" thick, and is available in eight fabric covers and four frame colors, allowing it to be employed without dominating the view. Assembly and installation were simple. The Chameleons were "audibly and measurably more effective" than KR's Echo Busters corner traps, and produced "undeniable" improvements in the midbass and bass. (Vol.32 No.9 WWW)

RealTraps MondoTraps: $330 ★
Corner MondoTraps: $370 ★
The MondoTrap is a large (57" H × 24" W × 4.25" D) acoustic absorber built from "double-density" rigid fiberglass and covered in a sound-transparent fabric. In addition to imparting to bass instruments a "fuller, clearer, more palpable" sound, the MondoTraps seemed to reduce a "glaze," allowing Jim Austin to hear deeper into the music. "Far from deadening the room," he said, "the MondoTraps made the music more involving." "I really liked what the Mondo Traps did in my room," adds KR, "although I have to agree with Jim (and my wife) that their appearance better suits a studio or dedicated audio room than a regular person's lifestyle." Adding four MondoTraps to WP's small listening room resulted in punchier, more coherent bass. Corner MondoTrap, designed to fit unobtrusively into a corner of a room, costs $350. (Vol.30 No.8, Vol.33 No.2 WWW)

RealTraps: $150-$600, depending on size and type ★
With these fiberglass panels set up across the junction of room boundaries and in corners, KR heard major improvements in imaging, detail, and soundstage width: "Every sound in the room, real or reproduced, is more defined in character and location." While KR was greatly satisfied with the results, he admitted that the panels were visually imposing: "The stand-mounted HF MiniTraps are in the way all the time." MiniTrap, $200; HF MiniTrap, $200; MondoTraps, $300; stands, $80. (Vol.28 No.1, Vol.29 No.11, Vol.33 No.2 WWW)

Stillpoints Aperture II acoustic panel: $800 (any color)
A refinement of the original Stillpoints Aperture—a 22" square wall-mounted room-treatment panel said to act as a diffuser, an absorber, and a resonator—the Aperture II is lighter in weight and easier to mount. According to MF, it's also better looking—and even more effective: "The illusion of my room's sidewall boundaries disappearing became even more convincing." (Vol.42 No.6 WWW)

Totem Acoustic Tuning Pods: $130/pair ★
The Beak is a precision-machined, bullet-shaped device, about 2" high × 1.5" in diameter, that's intended to be placed atop a speaker to control parasitic resonances. When the Beaks were used with the GoldenEar Triton Two loudspeakers, highs gained clarity and extension, percussion instruments had greater presence, and voices became more tightly focused, said RD. "The improvement wrought by the Beaks was such that I wouldn't want to be without them," he said. See also EL's Totem Forest review in Vol.33 No.1. (Vol.35 No.2 WWW)