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Thank you for purchasing KEF Reference Series loudspeakers. These have been designed to faithfully reproduce high quality sound over many
years of use and should provide realistic reproduction of music and speech. Please take a little time to read these instructions prior to use.
Important Safety Notice
Your KEF Reference Loudspeakers are tall, slim and extremely heavy. Installed correctly on a smooth, level surface, your speakers should be
entirely safe to listen to and to live with. However, if you have small children, large pets, the infirm, uneven flooring or unusually thick
carpeting in your home, then correct adjustment of the foot assemblies is imperative, if safe, stable, operation is to be achieved.
Warning: Do not touch the metal tweeter dome at the centre of the Uni-Q
®
driver array;
denting the dome will seriously impair performance.
1.0 INTRODUCTION
Since its formation in 1961, KEF has pioneered many innovations in loudspeaker technology and design. Your new Reference Series
loudspeakers contain one of the latest of these advances - the KEF Uni-Q driver array.
In this innovative KEF design, not only are the mid and high-frequency drivers on the same axis (co-axial), but their acoustic centres are also
on the same plane (co-planar). The profile of the mid-frequency driver’s cone modifies the directivity factor (or ‘Q’) of the high frequency
unit such that both drive units have the same directivity in the critical crossover region, where both drive units are operating at similar
frequencies. This unification of the ‘Q’ of the drive units lies behind the name “Uni-Q”.
Now incorporated in many KEF loudspeakers, the Uni-Q driver array yields immediate and readily audible sonic benefits. With no sharp
discontinuity in ‘Q’ at the crossover frequency, correct tonal balance is not confined to a single ‘sweet spot’ in the listening room and is
extended to cover a far broader area. With sound arriving in phase, the sound source is brought into the sharpest possible focus. With
properly recorded material and as part of a good quality system, well set-up, loudspeakers with KEF Uni-Q can reveal the location of each
musical voice in the stereo image with pin-point accuracy and with a much smoother response being maintained off-axis - where most people
listen - than before.
The ‘Next Generation’ Uni-Q array developed for this range is a sophisticated device whereby the midrange and high frequency drivers have
been symbiotically designed to take us one step closer to the ideal of a controlled directivity point source acoustic radiating system. The
165mm midrange section has a ‘Uni-Form’ cone profile which not only gives excellent midrange performance but also provides the optimum
waveguide for the coincidentally mounted tweeter. The new 25mm elliptical profile titanium dome tweeter has been developed using Finite
Element Analysis techniques to produce superior mechanical and acoustical behaviour. This is illustrated by the very high dome breakup
frequency of 34kHz - well above the frequency at which it crosses over to the new KEF Hypertweeter
TM
.
1.1 Overview of Common Features
The KEF Reference Series products covered by this manual are loudspeakers designed primarily to operate away from room boundaries (free
space), where the renowned stereo imaging of the Uni-Q driver array is at its best. However, a three position bass level adjustment feature
(Boundary Compensation Device) is included on models 201, 203, 205 and 207, which corrects the response to allow for placement close
to the front wall. All models use Reference matched drive units and crossovers that have been manufactured to laboratory-standards and
rigorously tested at every stage of production. The driver complement of each system reflects the increasing performance capabilities of each
model, particularly its ability to reproduce wider bandwidth at higher output levels.
In response to recent developments in ultra high frequency bandwidth source material all models include a new Hypertweeter as standard
to deliver flat response to 55kHz and useable energy to 80kHz. This unit is a development of the new 25mm elliptical profile titanium dome
and has its first break up mode above 40kHz. This mode is ‘notched out’ in the crossover network to keep the frequency response as smooth
as possible to the eventual high frequency roll off at around 60kHz.
Independent Driver Loading (IDL) is utilised for the bass sections of this new Reference Range. Using two identical bass units rather than a
single larger one has the advantage of maintaining a slim profile for the cabinet and subsequently wide and even sound dispersion. Internally,
however, a tall slim enclosure suffers from strong top-to-bottom acoustic standing waves which are very difficult to control. IDL divides the
enclosure into two half-height enclosures, one for each bass driver, with much improved internal acoustics. Because this configuration
increases the separation between the bass drivers the lower one is rolled-off before the top one to ensure smooth integration with the
Uni-Q array.
GB
English Instructions
