KEF R11 - Flagship Three-way Floorstanding Speakers
R11 is the largest model in the R Series and it combines four bass drivers and the latest generation Uni-Q for a powerful and refined sound. With hybrid aluminium bass drivers and a 12th generation Uni-Q for mid and treble the mighty KEF R11 is extremely capable. Using technology from KEF Reference it delivers clarity, finesse and serious bass.
Decades of experience and KEFs unbridled passion for music come together in the R Series. Combining innovations from the Reference Series with bespoke technologies the new R Series delivers more detail, deeper insight and greater excitement.
KEF’s quest for music perfection demands constant innovation. This is as true now as it was when KEF was founded in 1961. KEF's portfolio of acoustic design patents and innovations is unequalled. It leads the way in the use of sophisticated computer modelling techniques, such as finite element analysis and computational fluid dynamics. This drive for perfection is the reason the new KEF R Series features five major technological advances, many of which are derived from and inspired by the class-leading Reference Series. Innovations cover the whole audio spectrum and the entire loudspeaker, with developments ranging from a new version of the legendary Uni-Q driver to improved cabinet construction and refinements to other acoustically vital elements.
Derived directly from the Reference Series, the Shadow Flare is an innovative method of reducing harmful cabinet diffraction and one that allows the wonderful Uni-Q to work at its highest level. Shadow Flare is more than just a trim ring. It is a precision designed surface that extends the waveguide effect of Uni-Q. The tweeter no longer has line of sight of the cabinet edges, creating a ‘shadow region’ at the points where the potential for diffraction is highest, minimising the acoustic impact to negligible levels. The result is improved clarity, particularly when it comes to the subtle nuances of plucked strings and other percussive sounds
Advanced Bass drivers
To maximise bass performance in the new R Series, the dedicated low-frequency drivers are built using a two-part structure, where a shallow concave aluminium skin sits atop a paper cone. This stiffness combined with the cone’s unique geometry reduces additional resonances and delivers the pistonic movement that makes these drivers time so well. The new drivers also benefit from a completely redesigned magnet system that creates a more even magnetic field, and a design of suspension that reduces harmonic distortion for a cleaner, more precise sound. The result is tight, agile bass that digs out all the soul and punch available in the low end
Unique Cabinet bracing
All the cabinets in the new R Series benefit from Constrained Layer Damping bracing. Originally developed for the multiple award-winning LS50, this system utilises internal braces joined to the panels by a lossy interface rather than being adhered to it rigidly. This approach is highly effective at dissipating unwanted vibrations. A new internal bracing layout works alongside Constrained Layer Damping to create an incredibly inert platform from which the drive units can work their magic, enabling the R Series to deliver music as it is supposed to sound, without any unwanted extras.
Flexible port technology
When it comes to generating deep, articulate bass, port design is a vital element. The ports in the R Series are precisely positioned and feature innovative flexible walls. Using computational fluid dynamics, the flare and profile of each port is calculated to delay the onset of turbulence, while the flexible port walls prevent longitudinal resonances from colouring the midrange. The result is not only better bass, but cleaner sound further up the frequency range in the vital lower midrange area
Beautiful by design
Great design is timeless. KEF’s designers seek to create deceptively simple, elegant loudspeakers. While the drive unit arrangement is rightfully driven by acoustic, rather than aesthetic considerations, each loudspeaker is visually appealing without resorting to brash styling.
Understated design is complemented by carefully selected finishes. Conceived to be at home in either traditional or modern interiors, the R Series comes in a choice of two exceptionally sleek gloss finishes or a classic wood veneer. These finishes go deeper than just a base colour. Each speaker benefits from KEF’s tone-on-tone approach to design where the tweeter dome, driver cones, feet, spikes and KEF logo are tone matched to the finish.
The R Series was created to sound its best with or without grilles. The microfibre grille design is a first for KEF and not only looks beautiful but has a negligible effect on performance. They continue the tone-on-tone approach to match the various cabinet finishes and the edges are burnished for a suede-like effect.
KEF R11 Overview
Uni-Q driver array
1" vented aluminium dome tweeter
1 x 5" aluminium midrange driver
4 x 6.5" hybrid aluminum woofer
Bass-reflex cabinet with Constrained Layer Damping to reduce resonance
Rear-firing port with flexible port technology for clear, articulate
Choice of walnut, black gloss and white gloss finish
KEF R11 Specifications
Three-way bass reflex
- Uni-Q Driver Array
- HF: 25 mm (1 in.) vented aluminium dome tweeter
- MF: 125 mm (5 in.) aluminium cone
- LF: 4 x 165 mm (6.5in.) hybrid aluminium
400Hz, 2.9 kHz
Frequency Range (-6db)
Frequency Response (±3db)
46 Hz - 28 kHz
Amplifier Power (Recommended)
8 Ω (min. 3.2 Ω)
317.7 kg (each)
Dimension (H X W X D) With Plinth
1249.5 x 310.6 x 383.5 mm
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