Product details

DESCRIPTION

THX® Certified Ultra. Extreme Architectural Bass. Built for Cinematic Impact.

The KEF Ci250RRb‑THX is a powerhouse architectural subwoofer engineered for Extreme Home Theatre installations where uncompromising bass performance is essential. As a THX® Certified Ultra model, it delivers the deep, accurate, high‑output low‑frequency performance required for large home theatres and premium living spaces — all while maintaining the clean, discreet aesthetics of an in‑ceiling design.

At its core is an extra‑long‑throw 250 mm (10 in.) bass driver driven by a massive 150 oz magnet, allowing the Ci250RRb‑THX to produce thunderous, low‑distortion bass down to 20 Hz. When paired with KEF’s DSP‑equipped KASA500 amplifier, the Ci250RRb‑THX delivers exceptional depth, precision, and dynamic impact — perfect for music, movies, and gaming.

Designed for flexibility, the Ci250RRb‑THX achieves THX® Ultra certification when four units are powered by a single KASA500 amplifier. When two units are powered by one KASA500, the system meets THX® Select performance standards. This scalability makes it ideal for both dedicated cinemas and high‑performance media rooms.

Engineered with the design characteristics of professional studio monitors, the Ci250RRb‑THX recreates the tonal balance and low‑frequency accuracy intended by filmmakers. Explosions hit harder, musical bass lines gain weight and texture, and low‑frequency effects become more immersive  all without compromising architectural elegance.

With its Ultra‑Thin Bezel (UTB), paintable magnetic grille, and IP64 dust and splash resistance, the Ci250RRb‑THX blends seamlessly into any environment while delivering reference‑grade bass performance.

A perfect choice for large theatres, luxury living rooms, and high‑end residential installations

SPECIFICATION

Acoustic Performance

  • Frequency Response (±6dB) – Open‑backed — 20Hz (KASA setting)
  • Frequency Range (‑10dB) — 16Hz (KASA setting)
  • Maximum SPL — 109dB

Drive Units

  • LF — 250mm (10in.)
  • MF — –
  • HF — –

Amplification

  • Required Amplifier — KEF KASA500
  • Recommended Low‑pass Filter — 50Hz – 120Hz

Dimensions

  • External Diameter — Ø 346mm (13.62in.)
  • Depth — 153mm (6in.)
  • Cut‑out Diameter — Ø 300mm (11.81in.)
  • Mounting Depth from Surface — 147mm (5.8in.)

Weight

  • Net Weight — 5.6kg (12.3lbs)

Installation

  • Ceiling Thickness (Max) — 30mm (1.18in.)
  • Ceiling Thickness (Min) — 6mm (0.24in.)
  • Optional Rough‑in Frame — –

Rear Volume Requirements

  • Ideal Rear Volume — 140L
  • Minimum Rear Volume — 70L

Certifications & Compliance

  • THX Certification — THX® Certified Ultra
  • Safety Rating — IP64

Remarks

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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