KEF R11 Floorstanding Speakers - White (Non Meta)

KEF R11 Floorstanding Speakers - White (Non Meta)

** LAST PAIR **

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 R11 is extremely capable. Using technology from KEF Reference it delivers clarity, finesse and serious bass.

Uni-Q
KEF developed the very first Uni-Q driver in 1988 and has been progressively and relentlessly refined ever since. However, the reason why this signature innovation out-performs other approaches remains constant: 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 Uni-Q array found on the R Series represents a leap forward in sound
quality, hailing a new, 12th generation of this already iconic design. For starters, Uni-Q’s midrange motor system has been completely redesigned using KEF’s in-house simulation and analysis tools as well as decades of experience. The motor is responsible for converting the audio signal from an electrical voltage to a mechanical force. Ideally it does
this without any loss and without introducing any distortion. For a midrange driver, significant distortion can be generated due to modulation of the voice coil inductance. The motor in the new R Series has a shaped and undercut pole, and symmetrical aluminium demodulation rings, which combine to significantly reduce the inductance in the lower midrange so there is less variation as the voice coil moves. Another of the challenges faced when constructing a combination driver array like Uni-Q, is managing the minute gaps that separate the constituent parts. There is a narrow channel between the moving midrange voice coil and the static start of the tweeter waveguide. As air passes over this it creates resonances like blowing over the top of a bottle. Obviously, this gap is necessary to allow the midrange cone and voice coil to move, so KEF has improved the performance by opening up a cavity behind the drive units and then introducing damping material into the space created. This absorbs resonances and helps deliver more precise, purer treble performance thanks to reduced colouration.

Shadow Flare
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.

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.

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.

Specification