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Architectural Speakers


Frequently bought together


      The Extreme Architectural Subwoofer

      Engineered to deliver incredibly accurate and powerful bass, Ci250RRb-THX is the perfect addition to any music or home theatre system and an excellent partner to other KEF loudspeakers. Featuring an extra-long-throw 250mm (10 in.) bass driver with a massive 150oz magnet, Ci250RRb-THX delivers exceptional depth with the accuracy needed for an epic music, movie or gaming experience.

      Feel the detail in the deep

      In order to create the most immersive experience for music and movies, tremendous power is tempered with fine detailing. The extra-long-throw 250mm (10 in.) bass driver of Ci250RRb-THX, when driven by the KEF’s DSP-equipped KASA500 amplifier, delivers both in spades.

      As part of the Extreme Home Theatre line-up within KEF Architectural Speakers, Ci250RRb-THX is engineered to deliver high-fidelity sound experience for the most discerning music and movie lovers. Featuring a massive 150oz magnet in the motor system, Ci250RRb-THX delivers thunderous, low-distortion bass down to 20Hz with a maximum SPL of 109dB.  

      THX certified logo.png

      Ci250RRb-THX delivers ultra-high performance with true theatre sound quality for large theatres and living rooms and it is certified to THX® Ultra with the configuration of four Ci250RRb-THX powered by one KEF KASA500 amplifier. When the KEF KASA500 amplifier powers two Ci250RRb-THX, the performance meets the THX® Select standard.

      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 living room. The results? Action sequences are impactful, and dialogue-driven moments are natural and engaging.

      THX® certified subwoofers deliver the appropriate frequency response and high output and imaging quality of a traditional box speaker. This provides the best of both worlds - THX®surround sound performance from components that blend harmoniously with any interior.

      Designed to perform

      Engineered to be structurally robust with a premium aesthetic, the bespoke Ultra-Thin Bezel (UTB) offers the slimmest visible rim around the speaker while casting virtually no shadow. The paintable UTB and magnetic grille ensures the speaker seamlessly blends into the environment.

      Ci250RRb-THX is splash water and dust proof with IP64 certification. With a well-considered mechanical design, Ci250RRb-THX ensures ease of installation with the minimum of fuss.
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      The Details


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      Frequency Response (±6dB) Open-backed
      20Hz - KASA setting
      Frequency Range (-10dB)
      16Hz - KASA setting
      Max SPL
      Drive Units
      LF: 250mm (10in.)
      MF: -
      HF: -
      Required Amplifier
      KEF KASA500
      Recommended Low-pass Filter (Hz)
      50Hz - 120Hz
      Product External Dimension
      Diameter Ø: 346mm (13.62in.)
      Depth: 153mm (6in.)
      Cut-Out Dimensions
      Diameter Ø: 300mm (11.81in.)
      Net Weight
      5.6kg (12.3lbs)
      Mounting Depth from Surface
      147mm (5.8in.)
      Optional Rough In Frame
      Ideal Rear Volume
      Minimum Rear Volume
      THX Certification
      THX® Certified Ultra
      Safety and Regulatory Compliance
      Ceiling Thickness (Maximum)
      30mm (1.18in.)
      Ceiling Thickness (Minimum)
      6mm  (0.24in.)
      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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      In-ceiling installation 

      KEF reserves the right, in line with continuing research and development, to amend or change specifications. E&OE.
      Please visit our Ci Software Download page for more details.

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