R11 is the flagship of the new R Series range. Boasting four 165mm (6.5 in.) hybrid aluminium bass drivers, R11 digs deep and retrieves an exceptionally clean and musical low-end performance. Nestled in the centre of these lies the new 12th generation Uni-Q driver array. The 125mm (5 in.) midrange driver and 25mm (1 in.) aluminium dome tweeter combine to deliver an even more natural midrange and treble than believed possible at this price point. The result is a speaker that can pick out the softest details with grace and refinement, as well as deliver raw power and strength.

Uni-Q

Placing the tweeter in the acoustic centre of the midrange cone brings the acoustic ideal of a single point source closer to realisation. The new R Series benefits from a new 12th generation of the legendary Uni-Q which has been extensively designed using KEF’s in-house simulation and analysis tools. KEF’s engineers have been able to dramatically reduce colouration through reducing resonance in the minute gaps between Uni-Q’s separate elements. The resulting sound is purer, more precise and makes stereo imaging far more believable.

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.