At just 14 inches square, the KEF R400b may be compact, yet it packs an incredible punch. With a reinforced and braced sealed cabinet, the R400b houses twin 9-inch LF drivers powered by twin 250W class-D amplifiers. The drivers are mounted back-to-back, to create ‘force cancelling’. This means the opposing reactive forces are nullified, resulting in no cabinet agitation and a clean, fast, powerful bass performance – perfect for any serious home theatre system.

Model R400b
Design Powered Subwoofer (Sealed)
Drive Units Bass units:
LF: 2 x 225mm (9in.)
Frequency range (-6dB) 26Hz - 140Hz
Maximum output 111dB
Amplifier 2 x 250W (500W)
built-in Class-D
Low pass filter Variable 40Hz - 140Hz, 4th-order
Low level signal inputs RCA phono sockets
Speaker level inputs
Internal volume 22 litres
Power requirements 100V - 120V / 220V - 240V ~ 50 / 60Hz
Power consumption 600VA
Weight 21.5kg (47.4lbs.)
Dimension (H x W x D)
(with terminal & plinth) 365 x 330 x 351 mm (14.4 x 13 x 13.8 in.)