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KEF KUBE 12B - 12" 300W Compact Active Subwoofer

by KEF
£695.00 (inc. VAT)

The KEF KUBE Series of Subwoofers are a stylish and high-quality home subwoofer option, perfect for enhancing music and media playback.


The KEF KUBE Subwoofers are a great addition to any home cinema system or home sound system. They are stylish and well built, and will look the part in any room.

The KUBE12 is the largest of the three models and delivers an Earth-shaking bass response worthy of a home cinema setup or home sound system. This is perfect for those looking for the loudest and deepest sounding high-quality subwoofer.


The compact design also ensures that it will never take up too much space or be obtrusive in the area it is situated in.

The 300W Class-D amplifier will ensure a long lifespan, offering superb energy efficiency and reducing the overall weight of the sub.

KEF designs, engineers and assembles the driver, cabinet and circuitry in-house for the KUBE Subs, and also features bespoke iBX technology. All of this combined means the bass is crystal clear with no distortion or unwanted qualities, offering the best listening experience.



The KEF KUBE Subwoofers provide multiple connections and controls ensuring compatibility with any audio system. There is a standard RCA input, plus a phoenix terminal input for hard-wired speakers.

There is a master volume, as well as a frequency cutoff which will allow to you dial in just the right amount of bass to suit the system.


Positioning Presets

What really sets the KEF KUBE apart from the competition are the positioning presets.

There is a switch to toggle between, Wall/Cabinet, Corner or In-room, which can be selected based on where the KEF KUBE is physically located within the room. For example, if the sub is located next to the TV backed against a wall, then the 'Wall' option should be selected.

The sub will then tonally adjust itself to give the best possible sound from that location.


KEF KUBE 12B Key Features

  • 56bit 50 MIPS DSP preamplifier
  • iBX Intelligent Bass Extension: The DSP analyses your input signal and applies KEF’s iBX, allowing the subwoofer to play louder and remain dynamic at any listening level
  • Sophisticated proprietary DSP programming developed by KEF’s UK engineering team
  • KEF smartConnect intelligent inputs automatically detect mono or stereo and adjust the subwoofer volume level accordingly
  • Sealed for greater accuracy and delicate musical detail while allowing the KUBE subwoofers to be installed in a cabinet
  • Placement tuning presets for: Free standing, Wall/in-cabinet and Corner meaning the Kube sounds perfect wherever it’s installed
  • 300Watt Class D amplifier with DSP preamplifier/EQ

See SPECIFICATION tab for technical specs


    KEF KUBE 12B

    Design: Powered Subwoofer (Sealed)

    Drive Units: 1x 300mm (12")

    Frequency Response: 22Hz - 140Hz (-6dB)

    Maximum Output: 114dB

    Amplifier: Built-in Class-D, 300W RMS

    Variable Low Pass Filter: 40Hz - 140Hz & LFE

    Inputs: RCA Phono Sockets / Speaker Level Phoenix Terminal

    Power Requirements: 100V - 120V / 220V - 240V ~ 50 / 60Hz

    Dimensions: 410 x 393 x 410 mm / 16.1 x 15.5 x 16.1 in

    Weight: 20.6kg

    KEF KUBE 12B Subwoofer Manual

    KEF KUBE 12B Subwoofer Data Sheet