Description
KEF Reference 8b Subwoofer
Power with Accuracy, Handcrafted in the United Kingdom
The KEF Reference 8b is a twin-driver force-cancelling subwoofer of exceptional engineering depth, handcrafted at KEF’s home in Maidstone, Kent, to the same exacting standards as every loudspeaker in The Reference Series. Built for power with accuracy, the Reference 8b houses two 500-watt Class D amplifiers, each independently driving a 225mm long-throw, ultra-low distortion driver arranged back-to-back in a heavily braced, acoustically inert cabinet. This force-cancelling configuration eliminates the cabinet vibration that plagues conventional single-driver subwoofers, delivering low-distortion bass of effortless body, weight, and remarkable precision that is a worthy partner for any Reference Series loudspeaker system.
Force-Cancelling Twin-Driver Architecture
The Reference 8b’s twin 225mm long-throw drivers are mounted back-to-back within the cabinet, their opposing motions cancelling out the reactive forces that would otherwise cause the cabinet to vibrate and introduce coloration into the bass output. Combined with a heavily braced, acoustically inert cabinet construction, this force-cancelling arrangement achieves a level of low-frequency clarity, speed, and precision that single-driver subwoofer designs simply cannot match. Each driver is independently powered by its own 500-watt Class D amplifier with a switched-mode power supply and DSP-based control section, providing a total amplifier power of 1,000 watts and ensuring that both drivers operate with complete control and independence at all output levels.
Deep Extension and Controlled Output
The Reference 8b extends to 18Hz at minus 6dB in free-field conditions, with a frequency response of 24Hz at 90dB output in free-space mode within plus or minus 3dB, delivering the full depth and physical impact of the lowest recorded frequencies with remarkable composure. Maximum output reaches 110dB at 50Hz at 1m, while the variable low-pass filter provides frequency adjustment from 40Hz to 160Hz with selectable slopes of 12, 18, and 24dB per octave, alongside a dedicated LFE mode at 350Hz with an 18dB per octave slope. This flexibility ensures the Reference 8b integrates seamlessly with any main loudspeaker system, from the Reference 3 Meta to the Reference 5 Meta, in both music and home theatre configurations.
Comprehensive Connectivity and Reference-Grade Construction
The Reference 8b provides RCA phono and balanced XLR analogue inputs, speaker-level inputs for systems without dedicated subwoofer outputs, and an RCA link output for daisy-chaining multiple units. Available exclusively in Deep Piano Black, the Reference 8b measures 398 x 365 x 429mm and weighs 34kg, reflecting the quality of cabinet construction and amplifier engineering within. The 23-litre net internal volume has been optimised specifically for the Reference 8b’s twin-driver, force-cancelling configuration, ensuring the driver system operates within a precisely tuned acoustic environment at all times.
KEY FEATURES:
- Twin 225mm (9-inch) long-throw, ultra-low distortion force-cancelling driver configuration, handcrafted in Maidstone, Kent, United Kingdom
- Two independent 500-watt Class D amplifiers with switched-mode power supply and DSP-based control, totalling 1,000 watts
- Force-cancelling back-to-back driver arrangement in a heavily braced, acoustically inert cabinet
- Frequency range: 18Hz (minus 6dB, free field)
- Frequency response: 24Hz at 90dB output in free-space mode (plus or minus 3dB)
- Maximum output: 110dB (peak SPL at 1m, 50Hz)
- Variable low-pass filter: 40Hz to 160Hz with selectable slopes of 12, 18, and 24dB per octave
- LFE mode: 350Hz at 18dB per octave
- Inputs: RCA phono, balanced XLR analogue, and speaker-level inputs
- RCA phono link output for multi-subwoofer configurations
- Net internal volume: 23 litres
- Available in Deep Piano Black
- Dimensions: H 398 x W 365 x D 429mm, weight: 34kg
