The largest model in the R Series 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 R11is extremely capable. Using technology from KEF Reference it delivers clarity, finesse and serious bass.

Uni-Q
The evolution of KEF’s Uni-Q driver reaches its 12th generation in the R Series. Using simulation and analysis tools KEF’s engineers have been able to dramatically reduce colouration by cutting resonance in the tiny gaps between Uni-Q’s elements. The result is purer and more precise sound with stronger imaging.

SHADOW FLARE
Derived directly from the Reference Series, the Shadow Flare is an innovative method of reducing harmful cabinet diffraction for delicate high-frequencies. Shadow Flare is a carefully profiled transition surface which 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. The result is vastly improved fine detail, particularly when it comes to the subtle nuances of plucked strings and other percussive sounds.

LOW FREQUENCY DRIVERS
Bass is the very foundation of music; everything is built upon it and maximising bass performance is a vital building block towards pristine sound. R Series bass drivers are built using a two-part structure, where a shallow concave aluminium skin sits atop a paper cone. This great stiffness, combined with the cone’s unique geometry, delivers pure piston like movement to deliver punch and speed. To accurately control this mighty driver, KEF has also completely redesigned its magnet system to create a more even magnetic field. The overall result is more impressive and impactful.
CABINET BRACING
A solid platform is imperative for great sound. The new R Series benefits from Constrained layer damping. This system utilises internal braces joined by a ‘lossy’ interface and is highly effective at dissipating unwanted vibrations that would otherwise artificially change the sound and music.

FLEXIBLE PORT TECHNOLOGY
When it comes to generating deep, articulate bass, port design is crucial. The ports in R Series 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.