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.
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.
Frequency Response (±6dB) Open-backed
20Hz - KASA setting
Frequency Range (-10dB)
16Hz - KASA setting
LF: 250mm (10in.)
Recommended Low-pass Filter (Hz)
50Hz - 120Hz
Product External Dimension
Diameter Ø: 346mm (13.62in.)
Depth: 153mm (6in.)
Diameter Ø: 300mm (11.81in.)
Mounting Depth from Surface
Optional Rough In Frame
Ideal Rear Volume
Minimum Rear Volume
THX® Certified Ultra
Safety and Regulatory Compliance
Ceiling Thickness (Maximum)
Ceiling Thickness (Minimum)
ManualIndividual Information Spec. SheetArchitectural Speakers BrochureCi Series Spec. SheetCi Series Minimum Cabinet Volume ChartCutout TemplateProduct DrawingCi Series PamphletCi Accessory Guide
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.