KEF Celebrates 50th Anniversary with Blade
Big, clear sound is result of Uni-Q driver improvements and bonded bass drivers.
September 14, 2011 by Steven Castle

They’re much more impressive in person, by looks and sound.

KEF’s 62-inch-tall Blade speakers were built to celebrate the company’s 50th anniversary—and they are a delight, delivering super-clear and tight sound, even on the show floor of a noisy CEDIA Expo.

But … um … er … they’ll cost you a cool $30,000.  And despite the cost of admission, KEF reports already having sold 14 pair.

Lots to talk about here, but let’s start with the high-lacquered look of the sculptured glass-reinforced composite cabinets. You’ve got to wonder what these would look like in your best room.

Housed within each cabinet are four side-mounted 9-inch woofers, two pair back to back, and fronting the stage is what KEF calls a radically improved mid/high Uni-Q point-source driver.

KEF says the drivers are mounted symmetrically equidistant so their acoustic centers occupy exactly the same point in space and form a perfect point source. The clarity and imaging of the sound is excellent.

The Uni-Q drivers in front have large voice coils and flat surrounds to optimize dispersion. In addition, a tube behind the magnet prevents pressure buildup behind the tweeter dome, resulting in less distrotion. The Uni-Q driver array is fully decoupled from the cabinet to prevent any cabinet vibrations from muddying the sound.

The woofers are where it gets interesting. Four custom 9-inch drivers in each cabinet are mounted in two back-to-back pairs, each pair bonded in a force-canceling configuration that prevents the kinetic forces of the woofers from resonating within the cabinet.

The twinned pairs of bass drivers are mounted in discrete chambers separated by an internal partition. One cannot feel so much as a twitch on the cabinet.

Great care was taken with crossover components that were individually wired by hand for both reliability and sound quality by assuring the cleanest possible signal transmission, according to the company.

The 90-db (sensitivity) speakers can handle 50 to 400 watts of amplification at a nominal impedance of 4 Ohms. Frequency response is 40Hz to 35kHz +/- 3dB and
28Hz to 45kHZ +/- 6dB.

Standard finish options are pure gloss white or pure gloss black. For those with more exuberant tastes, 12 high-gloss custom lacquer finishes are available to special order.

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Steven Castle - Contributing Writer
Steven Castle is Electronic House's managing editor. he has been writing about consumer electronics, homes and energy efficiency topics for two decades. He is also the co-founder of GreenTech Advocates.

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