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KEF’s First Architectural Speaker with MAT™ 

Featuring innovative technologies including 12th Generation Uni-Q® driver array with Metamaterial Absorption Technology (MAT), patent-pending Cavity Radiation Control and Low Diffraction LF Aperture, Ci250RRM-THX is a truly revolutionary coaxial three-way architectural speaker that delivers immersive, high-fidelity soundstage with unmatched sonic excellence for large home theatres and living rooms.


Pushing technological boundaries

KEF always pushes the technological boundaries in its mission to create the best possible sound; Ci250RRM-THX is the physical manifestation of that drive.


Ci250RRM-THX delivers ultra-high performance with true theatre sound quality for large theatres and living rooms and it is certified to THX® Ultra. A deep understanding of the filmmaking process and surround sound is at the very heart of every THX® certified speaker system. Engineered with design characteristics of professional studio speakers, THX® recreates the tonal balance of the filmmaker's final mix in your home theatre or living room. The results? Action sequences are impactful, and dialogue-driven moments are natural and engaging.


Excluding Sales Tax
  • Nominal Impedance

    8 Ohms

    Sensitivity (2.83V/1m)


    Frequency Response (±6dB) Open-backed

    28Hz - 20kHz

    Frequency Range (-10dB)

    20Hz - 45kHz

    Nominal Coverage (Degrees)


    Max SPL


    Crossover Frequencies

    540Hz, 2.6kHz

    Drive Units

    LF: 250mm (10in.)
    MF: 100mm (4in.) Uni-Q
    HF: 19mm (0.75in.) vented aluminium dome with Metamaterial Absorption Technology1

    Recommended Amplifier Power

    50 - 250W

    Recommended High-pass Filter (Hz)

    30 - 60Hz

    Product External Dimension

    Diameter Ø: 346mm (13.62in.)
    Depth: 175mm (6.89in.)

    Cut-out Dimensions

    Diameter Ø: 300mm (11.81in.)

    Net Weight

    6kg (13.2lbs)

    Mounting Depth from Surface

    168mm (6.62in.)

    Optional Rough In Frame


    Ideal Rear Volume


    Minimum Rear Volume



    THX® Certified Ultra

    Safety and Regulatory Compliance


    Ceiling thickness (Maximum)

    30mm (1.18in.)

    Ceiling thickness (Minimum)

    6mm  (0.24in.)


    ManualIndividual Information Spec. SheetArchitectural Speakers BrochureCi Series Spec. SheetCi Series Minimum Cabinet Volume ChartCutout TemplateEASE GLL DATAProduct DrawingCi Series PamphletCi Accessory GuideWhite paper


    KEF reserves the right, in line with continuing research and development, to amend or change specifications. E&OE. THX, the THX logo, and Ultra are trademarks of THX Ltd. THX and the THX logo are registered in the U.S. and other jurisdictions. All rights reserved.

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