KEF Q400b Subwoofer


The final ingredient of your new Q system is of course the seductive Q400b subwoofer. A closed box design housing a 250mm (10in.) woofer driven by a 200W on-board Class-D amplifier, this discreet cube creates spectacular bass imagery - eloquent, musical and addictively physical. Anchoring the whole sound performance in an all-embracing sensation of immediacy, it completes the acoustic picture.


  • Deeper, tighter and more accurate bass.

    Featuring rigid new aluminium cone technology just like the Uni-Q array, the Q Series advanced bass driver is a tour de force in its own right. A die-cast aluminium chassis rigidly locates the high efficiency vented magnet assembly to prevent unwanted resonance, and the large (50mm) voice coil ensures impressive power handling. Its musicality is impeccable: seductively tuneful and well controlled, and on the floorstanding models, complemented by dedicated front-firing auxiliary bass radiators (ABRs).

    • Design: Closed-box subwoofer
    • Drive Units: 1 x 250mm (10in.)
    • Frequency Response: 28Hz - 140Hz (±3dB)
    • Crossover Frequencies: Cross Over Frequencies
    • Maximum Output: 110dB (SPL)
    • Amplifier Class: 200W built-in Class-D
    • Low Pass Filter Available: 40Hz - 140Hz, 4th-order
    • Low Level Signal Input:
      • RCA phono sockets
      • Speaker level inputs
    • Power Requirements: 100 - 240V ac ~ 50/60Hz
    • Power Consumption: 200VA
    • Dimensions: 335 x 330 x 330 mm (13.2 x 13.0 x 13.0 in.)
    • Weight: 13.6kg (29.9lbs)