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.