Any combination of a THX amplifier and THX loudspeaker will have about the same sensitivity as any other such combination. The reason each channel of a THX-certified amplifier is required to have an output…
search
KEF's Home THX speaker system is somewhat unusual in that it includes an active subwoofer. (While most Home Theater subs are powered types; it's just that few THX models are.) Although powered speakers have never enjoyed much popularity with American audiophiles, they can yield better results than the mix'n'match approach because each amplifier/driver combination can be optimized.
Devout subjectivists may scoff at the idea of setting subwoofer level by measurement, but the results I've gotten by metering it have been consistently spot-on, as long as the spl meter is placed at head height in the main listening seat. With that setting, program material has varied from somewhat lean to slightly bass-heavy, almost exactly according to expectation. Old LPs sound fat because of their LP equalization (which required low-end boost that flattened out at 100 rather than 50Hz), early stereo LPs are usually a bit lean, and recent audiophile recordings (Dorians, Telarcs,…
Sidebar 1: System
Front-end equipment used in this review included a Lexicon CP-3 Plus surround processor, EAD DSP-7000 D/A processor, Sony CDP-X779ES CD player, Sony DTC-2000ES DAT recorder, SOTA Cosmos turntable with vacuum hold-down, The Well Tempered Arm, and the Ortofon MC-3000 cartridge and its mating step-up transformer. Video equipment consisted of a Pioneer CLD-97 laserdisc player, Ampro 2000 video projector with the Dwin LD-2 line doubler, and a Stewart 6'-diagonal projection screen. Audio interconnects were Monster M-1000s, and the front loudspeaker cables were AudioQuest…
Sidebar 2: Measurements
I only measured the AV3 Left, Right, and Center loudspeaker, as there are no agreed-upon standards for surround-speaker performance. The AV3's impedance magnitude and electrical phase angle (fig.1) were measured with an industry-standard Audio Precision System One. As usual with a THX design intended to be used with a separate subwoofer, the sealed box is tuned to a highish frequency, this revealed by the magnitude peak at 93Hz. Overall, the AV3 appears to be quite a demanding 4 ohm load. Its sensitivity was lower than specification at a calculated 86dB/2.83V/1m (…
Sidebar 3: Specifications
AV3 LCR loudspeaker: Two-way sealed box system with two 61/2" cone woofers and three 1" soft-dome tweeters in vertical mirror-image configuration. Frequency response: 80Hz–20kHz, ±3dB. Crossover frequency: 3kHz. Nominal impedance: 4 ohms. Sensitivity: 90dB/W/m. Maximum output: 112dB. Amplifier requirements: 10–150W.
Dimensions: 23.6" H by 9.4" W by 7.1" D. Weight: 28 lbs.
Serial numbers of samples reviewed: 1618, 1645, 1652.
Price: $800 each, 1996; no longer available (2012).
AV2 surround loudspeaker: Three-way, reflex-loaded dipole with two…
Manufacturer's Comment
Editor: Thank you very much for the kind comments you made in your review of the KEF Home THX system. Words like "these are great Home Theater speakers..." are welcome indeed. Though you didn't find our Home THX system to be as good at music as, say, the ATC monitors or the Dunlavy SC-VIs, I find your comments about what the KEF THX system was primarily intended to do quite fair. So after saying my thanks, as it were, I would like to comment on a few things.
First, I'm sorry we confused you with the markings of the "Blend" control on the AV1 subwoofer…
Coincident Speaker Technology was known until recently as Concentric Speaker Technology. Under that name they marketed a line of cylindrical speakers covered in leather. All of their previous offerings have been discontinued along with their former name; the Troubador ($1495/pair), a handsome two-way housed in an asymmetrical cabinet, is the first of their new line of speakers. A bass module/speaker support à la the Wilson Puppy is also offered. Coincident's speakers are designed by Israel Blume and are direct-marketed in the US. There's a 30-day money-back guarantee and a five-year warranty…
Sidebar 1: Review context
The speakers were reviewed in my relatively small living room: 17" by 10" by 8" high in the primary dimensions, although it's part of an "open plan" living room/dining room/kitchen layout. I placed them along the long wall, which means I listened more or less near-field. Both pairs benefited greatly from rigid, nonresonant stands—I used a pair of Cliff Stone's 24" Foundation stands, which are filled with aggregate and were spiked through the carpet to the concrete subfloor. Although the Coincident loudspeakers are quite efficient and can be driven by modestly…
Sidebar 2: Measurements
With a calculated sensitivity of 91dB/W/m, the Troubador will play loud with only a few amplifier watts. Its impedance (fig.1) is also relatively benign. Fig.9 reveals the port tuning to lie at 55Hz, quite low for the enclosure size. Note the wrinkle in the impedance magnitude trace at 350Hz, a sign of some kind of cabinet resonance. And indeed, the cabinet vibrated strongly at that frequency. As the designer points out, the higher in frequency you can push a cabinet resonance, the smaller the effect it will have on music. And WP didn't remark on any midrange…
Manufacturer's Comment
Editor: It is with more than a little embarrassment that I must advise you that you were sent a pair of Troubadors that were not intended for the North American market but were specifically manufactured for a customer in Europe. This version of the Troubador uses a second-order crossover with the tweeter being phase-inverted. The regular version that is sold in North America and the Far East utilizes a first-order slope with both drivers connected in-phase. This crossover not only eliminates the low-treble suckout, but time-aligns the drivers as well.
The…