KEF Home THX Loudspeaker System Page 2
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, References) are as fat-sounding as one would expect from the use of wide-range omnidirectional mikes for their main pickups. Movie soundtracks followed the same pattern: Early stereo LDs are more or less bass-shy, and later ones increasingly have thunderous bass, often far beyond the point of wretched excess. (Give the public what it wants: bass, bass, and more bass!)
Shortly before KEF was to ship their THX system to me, a devastating review of it appeared in Home Theater Technology magazine. The reviewer, Stereophile expatriate Corey Greenberg, described the system as being in-your-face aggressive and excessively bright. The bullet-to-the-head was a succinct three words: "We hated it." Barely a day after I read that, I got a call from KEF informing me that delivery of my review system would be "slightly delayed." Seems it had gone back to the drawing board for a few last-minute modifications.
Suddenly, I felt a great unease. I've seen (or rather, heard) what usually happens when a manufacturer reworks a product in response to a bad review. What usually happens is that the "correction" overshoots the mark, resulting in a sound that's flawed in the opposite direction. So I asked KEF if I could also borrow a set of the speakers that got panned, for comparison with the new, ostensibly improved ones. I was told they didn't have any of them left. Not a single one. Nada. And this was before the new ones were even in production!
I had a vivid mental picture of men in white coats taking sledgehammers to KEF's inventory of the tainted speakers, like a farmer culling plague-infected chickens. (More likely they were stripping the old crossover networks out of them in preparation for the new ones.) So, while I wasn't exactly expecting this system to sound mediocreafter all, KEF has a long track record for making very respectable speakersI must admit that I approached these speakers with some misgivings.
First off, these speakers proved to be very easy to listen to, which would imply that they are very different from the ones reviewed in HTT. They sounded silky-smooth, relatively free from colorations, impressively authoritative, and they imaged like gangbusters! Center bunching from mono sources was very tight, even with the center channel turned off, and specificity from stereo sources was outstandingly good. Between-the-speaker images were stable and unambiguously placed.
These are great Home Theater speakers, with a low end that never once complained, no matter how much cinematic violence I threw at them. Bass was very deep, solid, and well-behaved, but only moderately well-defined. The lower midrange seemed a little elevated, producing a vaguely chesty quality that was consistent from recording to recording, and there was a slight "aw" coloration.
Highs were sweet to the point of dullness, despite a slight complementary accent from the two sets of power amps I tried. Detail was okay but nothing to celebrate, while the midrange was more laid-back than that of any THX system I've heard, which is (in my book) not a strong endorsement. With the speakers driven by the Boulder amplifiers, the system sounded a little less laid-back, but not by much of a margin.
With neither the Boulder amplifier nor the Parasound, did the KEFs have the immediacy necessary to elicit startle responses. This didn't seem as much related to frequency response as to speed; they lacked what I call "snap" and Martin Colloms calls "pace." It sounded as though the speakers hesitated very briefly before reproducing a sharp attack. They also seemed to darken timbres, as though the instruments making the sounds were larger than life. The effect was similar to playing an LP at reduced platter speed, except that there was no accompanying pitch change. These qualities were far less noticeable when viewing films than when listening to music, because the picture occupies much of the listener's attention, but they were quite noticeable when that distraction was removed.
Dynamic range was good, with less spurious compression than average, but more than I've heard from some speakers. (Notable for their lack of compression were a pair of powered monitors from an English firm called ATC, the original Fosgate Home THX speakers, and the massive Dunlavy SC-VIs, footnote 1). But while the KEFs were nonetheless quite capable of producing prodigious volume levels (THX calls for a max headroom of up to 105dB), they showed some evidence of stressa slight coarsening of texturesat levels above about 95dB.
To say that the KEFs sounded less like any Home THX speakers I've ever heard is not to say they were better music reproducers than the others. They were just quite different. All the others had several things in common: They reproduced the core of the soundthe musical and extra-musical midrangewith a high degree of accuracy and realism, they could play at very high levels without strain, and their low end was astonishingly good. But all have lacked the suavity, delicacy, refinement, and resolution of the legendary high-end speakers. Maybe there are some THX systems out there that have it all, but I haven't heard one.
But I don't believe this is a result of constraints imposed by the THX requirements. They are, after all, only minimum performance requirements, which define a level of acceptability below which a product cannot receive THX certification. There's nothing in the THX specs that says a speaker can't exceed those minima.
I think, rather, that the reason for THX speaker shortcomings is that some high-end manufacturers who sign on to the program do so more for its promotional value than out of a conviction that the THX specs have any relevance for music reproduction. For example,even though KEF signed up for the THX program, some statements in their instruction manuals suggest they haven't really signed on to it. For example, instead of recommending THX-certified amplifiers for driving their THX AV2s and '3s, they provide helpful suggestions for choosing appropriate amplifiers. They don't even acknowledge that THX amplifiers exist! The clincher, though, was their suggestion that their THX system should "supplement" one's music system rather than replace it.
So, did I "hate 'em?" Nope, I just didn't like 'em very much. As impressive as the KEF THX speakers were with noisy movie soundtracks, I found them to be unexciting music reproducers. They never gave me goosebumps, they never made me sit up and take notice, they never drew me irresistibly into the music, and they never inspired an orgy of revisiting all my favorite recordings. The best I can say for them is thatlike a bland personalitythey never irritated or offended me.
Sorry, KEF, but I think you overdid the course correction. I know you can do better with these, even within the "constraints" imposed by THX, because I've heard KEF speakers that were better. But until that happens, I can't recommend this system for music listening.
Footnote 1: The Fosgates were also designed by John Dunlavy.