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KEF R400B Subwoofer


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Shape Square
Warranty length 1 Year
Brand KEF Speakers

Tech Specs

- Design: Powered Subwoofer (Sealed)
- Bass units: 2 x 225mm (9")
- Frequency range (-6dB): 26Hz - 140Hz
- Maximum output: 111dB
- Amplifier: 2 x 250W built-in Class-D
- Low pass filter: 40 - 140Hz, 4th-order
- Low level inputs: RCA phono sockets
- Internal volume: 22 litres
- Power required: 100V-120V - 50/60Hz
- Power consumption: 600VA
- Dimensions (HWD): 365 x 330 x 351mm
- Weight: 21.5kg (47.4lbs.) 

Product Description

KEF R400b subwoofer may be compact, at just 14" square but it packs an incredible punch. With a reinforced and braced sealed cabinet, IT houses twin 9" LF drivers powered by twin 250W class-D amplifiers.

The back-to-back mounted drivers create ‘force cancelling’ so opposing reactive forces are nullified preventing cabinet agitation and giving a clean, fast, powerful bass performance – perfect for any serious home theatre system. Match with the KEF R series for a perfect home cinema experience.

KEF R Series

The brand-new R Series brings more affordability than ever to authentic audiophile levels of entertainment. Impressively fluent new Uni-Q driver arrays mix with strong new bass drivers and many inventive refinements to produce a rich, spacious sound image of such precision that it verges on the benchmark grade of KEF’s legendary Reference Series.

Uni-Q Drivers

The new Uni-Q MF/HF driver array is a masterpiece. Midrange response is amazingly fast and clean, thanks to a braced magnesium/aluminium alloy cone, with KEF’s Z-flex surround smoothing the transition to the front panel and a sturdy die-cast aluminium chassis that prevents resonance being transferred to the cabinet.

At the acoustic centre of the midrange cone is the sophisticated vented tweeter that endows KEF Blade with such startlingly pure HF response. With a large neodymium magnet and a computer-optimised dome structure so stiff that it operates pistonically over its entire working range, the upper registers are articulated with flawless precision – and to capitalise on Uni-Q’s point source characteristics.

The new bass driver is equally impressive. The combination of a massive vented magnet assembly and a large, lightweight aluminium voice coil driving a light, stiff and strong hybrid cone assures clean, deep and uncompressed bass output with superb dynamics and power handling.

Leading Technology

Inside the structure, every solo component endorses KEF’s technology management. Computer-designed crossovers enable the level of each driver to be refined for a slicker, flatter response. The R Series embodies a pivotal step forward in the gratification of music or film. By incorporating the high-end technologies of previous KEF masterpieces in a classically elegant format.

This gives serious audiophiles phenomenally accurate reproduction that neither adds to nor subtracts from the original recording: refined, spacious and exquisitely detailed. For those whose appreciation of true audio excellence outstrips their bank balance, look no further than new R series!

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