KEF KHT6000 ACE 5.1-Channel Speaker System

KEF's ACE technology bends the laws of physics.

In The Perfect Vision issue 57, KEF's flagship KHT9000 ACE 5.1-channel speaker received a "Golden Eye" award as one of best sounding systems of its kind. That system was technically advanced and chock full of engineering innovations, and it combined sleek styling with uncompromised sound quality (a claim few "lifestyle" systems can make honestly). The only catch: at a price of $7400, the KHT9000 system exceeded many enthusiasts' budgets, and I found myself wishing KEF would offer its impressive ACE technology in a less expensive package. With the introduction of its new KHT6000 ACE system, which starts at around $3700, KEF has done exactly that.

The KHT6000 system consists of four HTS6001 L/R/surround speakers, a horizontal-mount HTC6001 centerchannel speaker, and a PSW3500 powered subwoofer. The surrounds are essentially identical 3-way, 6-driver speakers housed in slender, roughly 23"-long enclosures with elliptical cross sections. Both feature KEF's proprietary ACE technology (see sidebar, below), which gives small speakers essentially the same driver-loading characteristics as much larger ones; in practice, this means KEF's compact L/R/C/surround speakers play louder and with much lower distortion than you might think possible. Pushing the envelope further, KEF offers ingenious "bass extender" floor stands that position the HTS6001s at ear level, but also act as bass-reflex cabinets that push bass response down to 75Hz (I wish KEF had positioned speaker binding posts on the tops—not the undersides—of these stands). Another ingenious touch is KEF's HTS wallmount system (included), where wallmounts serve not only as support brackets but as plug-in wiring connectors that automatically select the wallposition EQ curves built into the HTS6001s' crossovers networks. Completing the picture is KEF's remote-control-equipped, 300W PSW3500 subwoofer, whose elliptical shape mirrors that of the HTS/HTC modules on a giant scale. The key question, of course, is whether this new system offers the same delightfully natural sound that was the hallmark of the KHT9000 design. The answer? An unqualified "Yes!"

KEF has a reputation for building speakers that deliver natural sound with low coloration and effortless, unforced clarity; the KHT6000 system upholds this tradition. In truth, I imagine some listeners might find the KHT6000 s y s t e m ' s n a t u r a l sound too s e l f - effacing or subd u e d ; at first, t h e s y s - t e m can seem less exciting or "spectacular" than competitors designed to create dramatic, colorful, vivid first impressions. Over time, though, the KHT6000 system grows on listeners specifically because it doesn't impose a sound of its own; it is a true sonic chameleon whose rich palette of tone colors, timbres, and textures shifts to answer the demands of the music and film soundtracks you play. In short, you come to trust and then savor this system for its ability to tell you honestly how your material really sounds. TPV Editor Jonathan Valin calls this quality "transparency to the source," and I think it is one of the KHT6000 system's greatest strengths. The only downside is that the KEFs will also reveal any shortcomings your associated system components have, so choose wisely.

The KHT6000 system needs considerable break-in—40 hours or more—before it sounds its best. Initially, my review samples were bright, edgy, and dynamically compressed, but they loosened up beautifully over time, gradually becoming smoother, more focused, and more dynamically alive. So don't be discouraged if your KHT6000s take a while to smooth out; the easygoing clarity you'll enjoy later is well worth the wait.

Post break-in, the tonal balance of the KHT6000 system is quite neutral, with just the lightest touch of inviting warmth. Relative to the KHT9000 system, the KHT6000 system sounds actually a little cooler, just slightly more forward in the upper midrange, and a touch clearer and more analytical— though by no means sterile. In fact, the KHT6000 system may be more accurate than the KHT9000, though the larger system offers a pleasingly fullbodied sound that can help offset the occasional "iciness" of certain digital music recordings and film soundtracks. The KHT6000 and 9000 system subwoofers are cut from similar sonic cloth, offering a pleasing blend of low-frequency warmth, clarity, and extension. But where the KHT9000 sub is a big bass-reflex unit, KHT6000's is a smaller, infinite-baffle design that deliberately sacrifices a few Hertz of low-frequency extension for more defined and tightly focused overall bass. This is a wise tradeoff; it makes the woofer much less fussy about room placement. One practical suggestion: For best sub-to-satellite integration, try using an 80Hz crossover frequency (slightly higher crossover frequencies might make sense on paper, but in practice they often make the system's mid-bass sound too thick).