KEF 12 Inch 300W RMS Active Subwoofer - KUBE12b


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The Kube 12b is engineered to deliver the deepest bass for music and movies, if you want to feel the earth move look no further. Perfect for creating a deep and clean rumble in large rooms. The Kube 12b has a 300 Watts Class D amplifier and a large 12 inch driver as well as iBX technology to dynamically extend bass depth.


Hear new dimensions in sound with Kube subwoofers

The Kube 12b effortlessly unleashes explosive power. iBX technology dynamically extends bass depth and KEF’s unique ability to design, build and integrate the driver in-house takes optimisation to a whole new level. Delivering immersive music and home theatre sound that takes you to the heart of the performance.



Go deep or go home. KEF’s design and engineering team worked in chorus to develop iBX. This Intelligent Bass Extension algorithm creates an extended depth that unlocks the full potential of the custom driver. Giving you unparalleled precision and ultimate synchronicity between amplifier, driver and sealed cabinet.

Easy configuration

Kube subwoofers offer unmatched set up flexibility. A range of LFE, line and speaker-level inputs, phase selection and DSP controlled EQ settings help you get the best from a Kube. Put it in a convenient position, match it to any main speaker or type of music system, and start exploring new depths in the sound.



KEF is quite possibly the only high-end manufacturer that designs, engineers and assembles the driver, cabinet and circuitry in-house. This level of integration means we are commited to pure sound and the Kube stays true to that ideal. The result is a driver and amplifier that are perfectly in tune.

Analogue InputRCA phono sockets Speaker level inputs
InputsRCA phono sockets Speaker level inputs
Drive Units1 x 300mm (12in.)
Amplifier TypeBuilt-in Class-D
Recommended Amplifier Power300W RMS
Maximum Output114dB
Frequency Response22Hz - 140Hz (±3dB)
Variable Low Pass Filter40Hz - 140Hz & LFE
Unit MeasurementPiece
Power Requirements100V - 120V / 220V - 240V ~ 50 / 60Hz
DesignPowered Subwoofer (sealed)
Dimensions (with Rear panel and feet / H x W x D)410 x 393 x 410mm (16.1 x 15.5 x 16.1in.)

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