R SERIES

Exhilaration redefined
There’s nothing to match the thrill of hearing great music for the firsttime; that feeling of excitement when every note, phrase and chord
change is revealed in all its glory. The new KEF R Series has been
completely reengineered from the ground up to deliver a sound so pure,so revealing, that every listen is as exhilarating as that first one.
Decades of experience and our unbridled passion for music cometogether in the new R Series. It combines innovations drawn from theReference Series with new bespoke technologies to ensure the newR Series delivers more detail, deeper insight and greater excitement.
Every element of the new KEF R Series has been precisely engineered torecreate the exhilaration of hearing music for the first time. Because webelieve you want to experience that thrill again and again, just as much as
we do.

R starts with Reference
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 portfolioof acoustic design patents and innovations is unequalled. It leads theway in the use of sophisticated computer modelling techniques, suchas finite element analysis and computational fluid dynamics. This drivefor 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 otheracoustically vital elements. (An R Series white paper explains the myriad
technical advances in greater detail.)
As colouration is removed, clarity improved, and accuracy delivered atnew, higher levels, the performance of the R Series is raised to previously
unheard levels and your passion for recorded music is re-born.

Uni-Q

Shadow flareUni-Q
KEF developed the very first Uni-Q driver in 1988 and has been progressively and relentlessly refined ever since. However, the reason why thissignature 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 soundquality, 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 modulationof 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 theconstituent parts. There is a narrow channel between the moving midrange voice coil and the static start of the tweeter waveguide. As airpasses 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 acavity 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 thatallows 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 theacoustic 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 uniquegeometry reduces additional resonances and delivers the pistonic movement thatmakes these drivers time so well.
The new drivers also benefit from a completely redesigned magnet system thatcreates 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. Originallydeveloped 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 musicas 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 themidrange.
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.

Finishes
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.

Grilles
The R Series has been created to sound at its best without grilles. However, optional dedicated microfibre grilles are available for the R Series.
Each grille is crafted from 13 layers of material and has a wonderful suede-like feel, and thanks to 1801 precision-cut holes for each driver theperformance with the grilles in situ offers a considerable improvement on standard MDF acoustic cloth grilles, therefore minimises the traditional
compromise between great sound and driver protection. The magnetic fixings provide a secure, precise fit, in keeping with the clean styling of
the R Series.

Surround soundThe new R Series is your ticket for getting the best out of movies, delivering the natural, consistent sound essential for a phenomenal surroundsound experience.
The same sized Uni-Q array is shared by the R2c centre channel, the R3 stand mount and all three floorstanding models. Creating a consistentsound character, this ensures that focus is entirely on the film and not the equipment around the room.
Plus, the R Series includes the R8a, a closed box speaker designed to be either wall mounted for surround applications or used as a speakeron-top Dolby Atmos module. And with the addition of any of KEF’s class-leading subwoofers, the whole cinematic experience is felt, from thedeepest impact to the softest whisper.

Black Gloss

White Gloss

WalnutSpecifications

Model

R11

R7Design

Three-way bass reflex

Three-way bass reflex

R5
Three-way bass reflex

Drive units

Uni-Q Driver Array:
HF: 25mm (1in.) vented aluminium dome
MF: 125mm (5in.) aluminium cone
Bass Driver:LF: 4 x 165mm (6.5in.) hybrid aluminium

Uni-Q Driver Array:
HF: 25mm (1in.) vented aluminium dome
MF: 125mm (5in.) aluminium cone
Bass Driver:LF: 2 x 165mm (6.5in.) hybrid aluminium

Uni-Q Driver Array:
HF: 25mm (1in.) vented aluminium dome
MF: 125mm (5in.) aluminium cone
Bass Driver:LF: 2 x 130mm (5.25in.) hybrid aluminium

Crossover frequency

400Hz, 2.9kHz

400Hz, 2.9kHz

400Hz, 2.9kHz

Frequency range (-6dB)
Typical in-room bass response (-6dB)

30Hz - 50kHz
26Hz

33Hz - 50kHz
27Hz

38Hz - 50kHz
29Hz

Frequency response (±3dB)

46Hz - 28kHz

48Hz - 28kHz

52Hz - 28kHz

Harmonic distortion (90dB, 1m)<0.3% 120Hz - 20kHz<0.3% 120Hz - 20kHz<0.3% 120Hz - 20kHz

Maximum output

113dB

111dB

110dB

Amplifier power (recommended)

15 - 300W

15 - 250W

15 - 200W

Nominal impedance8Ω (min.3.2Ω)8Ω (min.3.2Ω)8Ω (min.3.2Ω)Sensitivity (2.83V/1m)

90dB

88dB

87dB

Weight *37.7 kg (83.1 lbs.)

31.4 kg (69.2 lbs.)

27.3 kg (60.2 lbs.)

Dimension (H x W x D)
with terminal *1249 x 200 x 383.5 mm(49.2 x 7.9 x 15.1 in.)1062 x 200 x 383.5 mm(41.8 x 7.9 x 15.1 in.)1025 x 175 x 343.5 mm(40.4 x 6.9 x 13.5 in.)Dimension (H x W x D)
with terminal with Plinth *1295.5 x 310.6 x 383.5 mm(51 x 12.2 x 15.1 in.)

1108.9 x 310.6 x 383.5 mm(43.7 x 12.2 x 15.1 in.)1071.4 x 271.6 x 343.5 mm(42.2 x 10.7 x 13.5 in.)Finishes

Black Gloss / White Gloss / WalnutBlack Gloss / White Gloss / WalnutBlack Gloss / White Gloss / Walnut

ModelR3R2cR8a

DesignThree-way bass reflex

Three-way closed box

Two-way closed box

Drive units

Uni-Q Driver Array:
HF: 25mm (1in.) vented aluminium dome
MF: 125mm (5in.) aluminium cone
Bass Driver:LF: 165mm (6.5in.) hybrid aluminium

Uni-Q Driver Array:
HF: 25mm (1in.) vented aluminium dome
MF: 125mm (5in.) aluminium cone
Bass Driver:LF: 2 x 130mm (5.25in.) hybrid aluminium

Uni-Q Driver Array:
HF: 25mm (1in.) vented aluminium dome
MF/ LF: 130mm (5.25in.) aluminium cone

Crossover frequency

400Hz, 2.9kHz

400Hz, 2.9kHz

2kHz

Frequency range (-6dB)
Typical in-room bass response (-6dB)

38Hz - 50kHz
30Hz

64Hz - 50kHz
49Hz

96Hz - 19.5kHz-Frequency response (±3dB)

58Hz - 28kHz

74Hz - 28kHz

105Hz - 18.5kHz

Harmonic distorition (90dB, 1m)<0.3% 130Hz - 20kHz<0.3% 120Hz - 20 kHz<0.3% 200Hz - 20kHz

Maximum output

110dB

110dB

106dB

Amplifier power (recommended)

15 - 180W

15 - 200W

25 - 150W

Nominal impedance8Ω (min.3.2Ω)8Ω (min 3.2Ω)8Ω (min.4.2Ω)Sensitivity (2.83V/1m)

87dB

87dB

86dB

Weight *13.5 kg (29.8 lbs.)

16.9 kg (37.3 lbs.)

4.45 kg (9.8 lbs.)

Dimension (H x W x D)
with terminal *422.2 x 199.6 x 335.5 mm(16.6 x 7.9 x 13.2 in.)175 x 550 x 308.5 mm(6.9 x 21.7 x 12.1 in.)173.8 x 174.6 x 259 mm(6.8 x 6.9 x 10.2 in.)Finishes

Black Gloss / White Gloss / WalnutBlack Gloss / White Gloss / WalnutBlack Gloss / White Gloss* Measurement per unit

* Measurement per unit

Visit: KEF.com for more about KEF and its products.
KEF reserves the right, in line with continuing research and development, to amend or change specifications. E&OE.

03.2021 | R Series