KEF REFERENCE 201/2 Service manual

VISIONARY
Quality. Honesty. Innovation.
These qualities are why KEF commands such
respect among audiophiles. Ever since the
pioneering acoustics engineer Raymond Cooke
founded the company in 1961, KEF innovation
has helped to shape the evolution of modern
audio technologies.
His vision holds true today, in a brand driven by
original thinking and engineering integrity rather
than passing fads. No other manufacturer
can claim such a distinguished design pedigree,
from revolutionary driver concepts and the use of
radically new materials to a host of patented
refinements that transform the listening experience.
But making great loudspeakers is an art as much as
a science, and these innovations are all designed to
enrich that emotional experience by achieving the
clearest, purest sound.
Welcome to the world of KEF Reference Series.
Photograph : Martyn Goddard. Courtesy Sunday Telegraph Colour Supplement.

HERITAGE
In a world where everything is relative,
KEF Reference Series has always stood for
absolute standards.
The design approach has always been consistent:
to give some of the world’s most gifted acoustics
engineers the freedom to set a new performance
yardstick. After years of research and painstaking
development, the resulting conceptual
breakthroughs are built into prototypes that are as
close to perfect as possible.
After exhaustive measurements and listening tests
using different media under anechoic conditions and
in real rooms, each prototype is fine-tuned to
become ‘the reference’ to which every production
version must conform. Each speaker is then
hand-assembled by a skilled craftsman who matches
the performance of each driver to within 0.5dB.
It’s a process that takes time, skill and patience – but
it creates a range of loudspeakers that continue to
redefine the boundaries of sonic performance.
Meet the new benchmark.

PRECISION
As KEF’s signature technology, the Uni-Q concept is
renowned for its uncannily natural sound and stable
imaging. In the Uni-Q configuration the tweeter is
mounted at the centre of the midrange cone so that
their acoustic centres are at the same point in space.
The outputs from the two units are thereby time
aligned and will sum perfectly for all listening
positions. The profile of the midrange cone controls
the directivity of both drive units so it acts not only
as a superior midrange radiator but also as the
optimum waveguide for the upper registers.
Now, after nearly two decades of continuous
development and a host of new patented
refinements, every component of this uniquely
advanced driver array has been redesigned to
achieve a quantum leap in performance.
The tweeter now has a vented motor system with
three rare earth magnets, and a unique braced dome.
The midrange unit has a low profile surround that
eliminates edge diffraction effects.These innovations
take Uni-Q performance to a new level.
Dispersion is wider still. Power response is even
more uniform.Tonal balance is more realistic across
both direct and reverberant fields. Multi-channel
imagery is clearer and more accurate than ever.
UNI-Q®

AUSTIN
Interesting things can happen when you push
beyond normal limits.
Senior Acoustics Engineer, Dr.Andrew Watson and
the Reference Series design team set out to build
the most natural sounding loudspeakers possible,
irrespective of cost or practical constraints.
The ‘Austin’ concept was the result – a technological
tour de force standing two metres high and weighing
more than 120 kilos apiece. Awesome is the only
word to describe how they sound.
The project became the technology testbed for the
new Reference Series. The two-piece compound
titanium tweeter dome whose pistonic motion
reproduces higher frequencies with such effortless
clarity; the new shallower midrange cone that
disperses the soundfield so broadly; the elegant
fourth-order crossovers, computer-optimised for
superior driver integration.
Big ideas. Big sound. Big benefits.
GROUNDBREAKING

CROSSOVER
The new Reference Series responds even more
musically than its acclaimed predecessors by combining
design innovation with an exceptionally rigorous
approach to the specification of each component.
The crossovers, for example, are computer-modelled
to optimise amplitude and phase behaviour for the
smoothest possible integration. Not only are
the crossover boards decoupled to isolate them
from cabinet wall vibration and to stabilise them
against the high acoustic pressures inside, but the
multi-board construction also eliminates crosstalk
between the different sections.
High saturation iron powder core inductors are
selected for bass sections, where large inductance
values and low resistance are required; air cored
inductors are used elsewhere for their superior
linearity. Similarly, there are high quality bipolar
capacitors for low frequencies, and very low loss
polypropylene capacitors for the upper ranges.
High power rated wire-wound resistors are
specified throughout to assure minimal
compression and maximum linearity.
Hidden away as they are, as much care has gone
into the design of these aspects as those that are
visible. And the difference is plain to hear.
INNOVATION

DEDICATED LOWER MIDRANGE
KEF’s high-end Uni-Q loudspeakers have had the
benefit of a dedicated lower midrange driver since
1989. By allowing each section of the frequency
range to be optimised for its specific role,
this configuration creates much smoother
transitions between the Uni-Q array and the bass
drivers. The integration is so precise that it’s
virtually impossible to hear that the sound is being
generated by a four-way configuration.
The resulting acoustic performance is markedly
superior, with the delicacy and precise imaging of
KEF Uni-Q perfectly complemented by the scale
and impact of a truly assertive bass section.
The 250mm (10in.) lower midrange driver of the
Model 207/2 has a distinctive chrome ‘phase plug’
at its centre to optimise its acoustic response.
A lightweight neodymium magnet assembly allows
the unit to be mechanically decoupled from the
cabinet to minimise the transmission of vibration
and to ensure that its sonic purity matches that of
the bass and Uni-Q sections.
SOUND THINKING
KEF Reference Series cabinets are works of art in
themselves, quite apart from all the high-end
technology they enclose.
It’s not just the sumptuous choice of finishes
(although the silky pale Satin Sycamore and the
sheer depth of the High Gloss Cherry, American
Walnut and Piano Black finishes do admittedly hint
at the uncompromised build quality).
What’s so special about these curved section
cabinets is how they perform – and why.
Precision engineered from beech ply, they’re
designed to eliminate every unwanted vibration
that would otherwise muddy the sound.
Massive internal bracing tailors the volume of each
enclosure to the exact parameters of its drive
unit, and mechanical and acoustic damping ensures
an inert structure that never colours the
inherently natural sound.
With independent driver loading and KEF’s proven
decoupling techniques, these are cabinets that do
nothing to mask the performance of the
components inside.
No panel resonance. No standing waves.
No stray reflections. No box colorations.
Just pure, sweet sound.

ATTENTION TO DETAIL PRIDE
For all the technological innovation inside the new
Reference Series, the personal commitment to
build quality remains true to the uncompromised
standards originally set by Raymond Cooke.
The exceptional finish speaks for itself, but the same
obsessive attention to detail applies to the parts you
never see. KEF’s own graded OFC (Oxygen Free
Copper) cable is soldered by hand and the drivers
are magnetically shielded to prevent interference
with your TV. Signal transmission is optimised on
all models by having three pairs of fully shrouded
gold plated WBT®terminals to allow tri-wiring
or tri-amplification.
Naturally, performance can be fine-tuned for
your room acoustics. The KEF Uni Balance
feature allows you to adjust bass output to
compensate for the proximity of the
loudspeakers to the walls. At the high frequency
end, a four-position adjustment gives ample
‘brightness’ control to compensate for the
room’s sound absorption characteristics.
The Reference concept is all about pleasure
that lasts. So when you open the polished
wooden case that comes with your loudspeakers,
you’ll find a certificate of authenticity signed by the
craftsman who made them, along with your
Reference Series manual and all the accessories
you’re ever likely to need .

MODEL 207/2
In a word, bliss. As KEF’s flagship loudspeaker,
every inch of Model 207/2 is designed to make
what you hear sound totally real.
This is where all the latest KEF technology
breakthroughs find their finest expression; sound
quality, bandwidth and dynamics are second to
none. Bass extension is phenomenal, thanks to a
pair of 250mm (10in.) ultra-low distortion drivers
independently housed in 70-litre reflex enclosures.
A dedicated lower midrange driver of the same
size adds the control and finesse required in this
crucial register while assuring perfect integration
between the bass drivers and the stunning new
Uni-Q array. And with its unrivalled linearity, the
Uni-Q has exceptionally wide dispersion and
unerringly precise reproduction across both
midrange and high frequencies. By faithfully
tracking every last subtlety of the recording, it
generates a soundfield of startling realism.
This technological sophistication produces
loudspeakers that seem to disappear: all you
experience is the sensation of actually being close
to the original source of the sound.
ICONIC

TRUTONE
Mastering is the critical final step in the production
of CD, DVD or vinyl releases, and Trutone
Mastering Labs is one of the world’s most
respected exponents.
With state of the art studios on the Manhattan
site of the former Record Plant used by Lennon,
Springsteen and The Who, the company has a
distinguished history of high-end mastering and
production. Trutone’s artists read like a roll call of
greats, from James Brown and Whitney Houston
to Steven Sondheim, Cyndi Lauper and The Killers.
As well as being fully equipped to enhance and
refine recorded sound,Trutone’s highly creative
mastering pros, Carl Rowatti and Joe Lambert,
have a genius for making a good master sound
great. When it comes to music, no one listens
more discriminatingly.
In any acoustically correct listening environment,
audio monitor fidelity is paramount. And after
auditioning major high-end brands,Trutone found
that KEF Reference Model 207 consistently
reproduced the most faithful sound.
According to chief mastering engineer Carl Rowatti,
“Sound quality is our business, so our audio
systems have to perform equally well across every
type of music from hip hop to classical.
Only Reference sounded really great with every
genre. They’re incredibly accurate, and there’s
nothing they can’t handle.”
IN THE MIX

MODEL 205/2
A giant among full bandwidth floorstanders.
Whether you prefer Stradivarius or Stratocaster,
Model 205/2 is a sublimely musical performer
when it comes to conveying the nuances of
recorded sound.
The new Uni-Q array is so perfectly attuned to
reproducing the human voice that vocals acquire
previously unheard-of definition. The improved
balance between direct sound, early room
reflections and the reverberant field delivers an
extraordinarily realistic performance without
losing any of the Uni-Q benefits of precise imaging,
spaciousness and unconstrained vertical response.
Paired ultra-low distortion long-throw 200mm
(8in.) LF drivers deliver hefty bass extension with
virtually no distortion over a commanding sound
stage, and response is deliciously smooth right
across the frequency range .
DEFINITIVE

VALUED
The Reference Series story is ultimately about
people more than technology – the engineers and
designers who create it, the highly skilled
craftsmen who build it, and most important of all,
the people who enjoy the end product.
The point is, everyone in the Reference Series
team is driven by a genuine passion for delivering
a better customer experience by making
outstanding loudspeakers. Naturally, they embrace
the most advanced technologies and materials
as tools in this pursuit. Of course they’re
continually seeking efficiency gains to control cost
without compromising quality. But above all,
it’s their talent that sets KEF apart – that,
and taking the trouble to find out exactly what
our customers want.
Senior Acoustics Engineer, Dr.Andrew Watson
sums up the difference perfectly,“Our philosophy
is not Uni-Q, ACE or any of the other
technologies we’ve pioneered over the years.
What KEF stands for is the pursuit of natural
sound reproduction through intelligent
engineering.”
And the result is sound that makes your hair stand
on end.
SYNERGY

MODEL 203/2
The three-way bass reflex Model 203/2 shares
the technical virtuosity that makes the larger
floorstanders great, but in a more compact
package – the same new generation KEF
technologies, the same carefully chosen high
quality components and the same unrivalled
build quality.
Computer optimised audiophile grade crossovers
ensure that transitions are imperceptible between
the radical new Uni-Q array and the two 165mm
(6.5in.) LF drivers. And with the latest ‘overhung’
long coil/short gap motor systems and
lightweight reinforced diaphragms, bass response
is unusually open, with negligible distortion,
even when played loud. Stereo imaging is
immaculate, wherever you sit.
Whether for music, home theatre or gaming,
it’s the perfect compromise between size
and performance.
LUCID

MODEL 201/2
Like the movement of a precision chronometer,
Model 201/2 proves that engineering excellence
has nothing to do with size.
A three-way bass reflex design, Model 201/2
packs all the benefits of the latest Reference Series
technology into an elegantly compact cabinet.
The same sensational new Uni-Q array,
with its lightweight neodymium magnet
assembly, braced compound tweeter dome and
computer-optimised waveguide. The same
ultra-low distortion LF drive unit for solid bass
extension with uncompromised clarity. The same
decoupled crossover boards with meticulously
specified inductors, capacitors and resistors.
And with magnetic shielding and Uni-Q’s
inherently wide dispersion characteristics, the
freedom of positioning is second to none –
there’s even a rubber mat in case you prefer
horizontal mounting for nearfield monitor use in
recording studios.
As a result, Model 201/2 delivers a fluent,
full-bodied and intensely musical sound quality
that is out of all proportion to its modest
dimensions. For many, it’s the ultimate full range
bookshelf loudspeaker .
SATISFYING

EXTON STUDIOS
To showcase the extraordinary acoustic
capabilities of the new Reference Series,
KEF turned to Octavia Records, the multiple
award-winning classical music label. With a list of
credits extending from Art Garfunkel to
Ashkenazy, the Tokyo-based studio is an
acknowledged centre of excellence for high-end
audio recordings.
The company’s Exton division is headed by
Tomoyoshi Ezaki, an engineer/producer known
throughout the industry for the obsessive
attention to detail with which he pursues his
quest to reproduce original sound as perfectly
as possible.
Ezaki and his team duly set about remastering for
KEF a 2001 performance of the Bach Toccata and
Fugue in D minor by the celebrated Czech
organist Ales Bárta. The result is a five-channel
SACD (Super Audio Compact Disc) direct stream
digital recording of breathtaking clarity and finesse.
“It’s a recording that tests the dynamics of the
new Reference Series as well as their intense
musicality,” commented Mr Ezaki, “it illustrates
how incredibly revealing these loudspeakers
are – not only can you hear the tiniest detail,
however minute, the lack of distortion is
phenomenal. Even to a sound professional,
the illusion of presence is uncanny.”
RECORDING EXCELLENCE

MODEL 204/2c
Movie stars don’t come more charismatic than
this; expansive, engrossing and disarmingly natural.
Together with breathtaking sonic accuracy and
spatial precision, these are the qualities a great
centre channel loudspeaker aspires to – and the
pleasingly slim Model 204/2c has them all.
No wonder. With a quartet of ultra-low distortion
165mm (6.5in.) bass drivers flanking a new
generation Uni-Q array, it combines real muscle
with the sensitivity to articulate all the subtleties
in the soundtrack. Transitions are seamless,
thanks partly to the bass array being progressively
filtered so that the two outer woofers roll off
before the inner pair.
It transforms passive viewing into total involvement.
Dialogue and vocals acquire spine-tingling immediacy,
whether whispered or yelled; on screen action
becomes startlingly real. Tosca or Tarantino, it’s an
addictive experience.
CENTRE STAGE

MODEL 202/2c
The same enhanced point source effect.
The same broad, even dispersion characteristics.
The same essential truthfulness.
The three-way bass reflex Model 202/2c has all the
acoustic virtuosity of the 204/2c, but with a single
165mm (6.5in.) bass driver on each side of the
mechanically decoupled Uni-Q array. And as with
the rest of the range, the HF magnet assembly is
vented to reduce acoustic pressure behind the
braced compound dome. The result is smooth,
dynamic response that faithfully follows every
nuance of the recorded signal.
For the listener, it adds up to a genuinely uplifting
listening and viewing experience. Superbly detailed.
Honest. And deeply satisfying.
UNDERSTUDY