The company was founded in 1961 by Raymond Cooke OBE near Maidstone in Kent. Cooke, an ex-BBC Electrical Engineer, was keen to experiment with new materials and technologies in order to create products with superior acoustic quality that could reproduce recordings as natural as the original performance. From the very beginning, the pioneering inventiveness of KEF loudspeakers was undeniable and now for several decades, audiophiles around the world have revered KEF for its innovative, high-performance loudspeakers.
The cutting edge of loudspeaker design
When we gave our engineers free rein to create a fitting showcase for our technology leadership, they developed a revolutionary prototype that looked and performed like no other: Concept Blade, the world's first single apparent source loudspeaker.
Its phenomenal sonic capabilities met with such praise that we decided to produce an edition that serious audiophiles could actually own. After two years of painstaking refinement - and in time to mark 50 years of KEF innovation - Blade is the result.
Conceived from the outset to extend the boundaries of high end audio, it’s a unique synthesis of innovative engineering and groundbreaking design based on a new architecture that achieves the ideal point source to which all speakers aspire. This is because the four sophisticated new bass drivers are configured so that their combined acoustic centre occupies exactly the same point in space as that of the Uni-Q HF/MF array, so the sound appears to emanate from a single, flawlessly coherent source.
single apparent source Uni-Q bass design & designers
Sculptural and acoustically inert, the slender parabolic enclosures are engineered never to interfere with the purity of the output. The advanced new hybrid cones are so light and rigid that their natural break-up point is never reached within the required frequency range. Inside, you find ingenious new venting, bracing and wave management technologies. Meticulously specified, super-premium components - every one operating so comfortably within its performance envelope that you experience noticeably more precise imaging than is possible with conventional speakers. What you hear sounds as if it’s live - emotionally engaging, richly musical and effortlessly natural. A revelation, pure and simple.
Single apparent source
Like listening to one voice rather than many, sound from a single source is inherently clearer. Not only are the acoustic centres of the HF and MF drivers in the Blade’s Uni-Q array coincident, but the four LF drivers are mounted symmetrically equidistant from it so that their acoustic centres occupy exactly the same point in space.
This single apparent source configuration is what makes the Blade so gratifyingly coherent across the frequency range, with noticeably more precise imaging than is possible from any conventional speaker.
What you hear sounds as if it’s being performed live right in front of you.
Advanced acoustic technologies
Uni-Q driver array
MF hybrid cone
So light and rigid that it never reaches its natural break-up point, the Blade’s hybrid MF cone has an outer skin of lithium/ magnesium/ aluminium alloy braced at the back by a precision-engineered skeleton of liquid crystal polymer, which not only aids stiffness but also vents the confined space between the cone and voice coil. By optimising sensitivity and transient response, this unique combination reproduces upper midrange frequencies with an accuracy that allows you to enjoy the full subtlety of emotionally nuanced performances, especially with vocals and keyboards.
After two years of intensive development, the four powerful new 9” (225mm) LF drivers of the Blade are perfectly integrated with the Uni-Q and generate an even deeper, cleaner and more authoritative bass than the larger units in the original concept.
By maximising extension in line with output, this formidable array is capable of delivering seismic punch when required while also retaining the delicacy and musicality you would experience if you were in the room with the original artists.
Conventional speaker generating cabinet resonance With Blade, the forces cancel each other out to minimise resonance
To avoid dissipating the energy of such potent bass drivers in exciting the cabinet (and thereby generating resonance, especially at high volume), the large kinetic forces involved are cancelled out by mounting the LF drivers rigidly together, back-to-back.
By minimising cabinet colouration, this highly effective configuration partly accounts for the Blade’s natural-sounding and engagingly musical performance.
Discrete bass chambers
The twinned pairs of bass drivers are mounted in discrete chambers separated by an internal partition. By increasing the frequency of any internal standing waves to way beyond the crossover point, this reduces the need for damping material (which can otherwise impair bass quality). Nothing has been overlooked in the quest for the ultimate clarity, right across the frequency range.
Attention to detail
With a speaker as ambitious as the Blade, short cuts are out of the question. Everything has to be as right as it can possibly be.
Terminals & terminal links
Two pairs of the finest audiophile quality WBT connectors allow bi-wiring or bi-amping to optimise the retrieval of low level detail in the music.
Low order crossovers
The simple low order crossovers specified for the Blade employ the best components available, carefully selected by a rigorous auditioning process so that every part of the signal path is fine-tuned for maximum clarity.
The patented screw-in linking plugs are to full audiophile specification (as well as simplifying set-up by eliminating fiddly wiring links). All the crossover components are individually wired by hand rather than mounted on a conventional printed circuit board. As well as being more environment-friendly, this optimises both reliability and sound quality by assuring the cleanest possible signal transmission.
The challenge was to design an acoustically efficient enclosure for a sizeable speaker whose driver configuration demanded large capacity at the upper portion, without looking at all bulky.
Initially, our team worked alongside Eric Chan of New York-based ECCO Design to create a distinctive visual identity for a speaker of such towering performance capabilities. As functional as they are beautiful, the resulting cabinets are like works of art in their own right - indeed, their form was inspired by Brancusi’s seminal Modernist masterpiece ‘Bird in Space’.
Tapering gracefully from top to bottom and from front to rear, the slim proportions made possible by the orientation of the bass drivers give the Blade a sculptural presence in its own right, with a single continuous keyline describing a taut, seamless curve along the back edge and over the top.
This award-winning form was dictated by acoustic considerations rather than mere styling: the gentle radius of the front face presents the sound with no discontinuity to mar its clarity. The cabinets are constructed from a glass-reinforced composite, an inert and exceptionally rigid material that lends itself to forming the complex parabolic curves that help to eliminate any internal standing waves that might otherwise blur the output.
Design Three-way bass reflex, Single Apparent Source driver configuration
Drive units Uni-Q driver array:MF: 125mm (5in.) Li-Mg-Al /LCP hybrid coneHF: 25mm (1in.) Al domeBass units:LF: 4 x 225mm (9in.) with force cancelling
Frequency response 40Hz - 35kHz +/- 3dB28Hz - 45kHZ +/- 6dB
Harmonic distortion 2nd and 3rd harmonics (90dB/1m):<0.5% 40Hz - 100kHz<0.2% 200Hz - 10kHz
Crossover frequencies 350Hz, 3kHz
Amplifier requirements 50-400W
Sensitivity (2.83V/1m) 90dB
Maximum output (SPL) 117dB
Nominal impedance 4 Ohms (3.2 Ohms min.)
Weight 57.2 kg (126 lbs)
Dimensions(H x W x D) 1590 x 363 x 540 mm62.5 x 14.3 x 21.2 in.
Standard finishes Gloss black or gloss white
Custom colours Garnet, Sapphire, Grigio, Racing red, Racing blue,Pale gold, Orange sorbet, Graphite, Stardust,Lemon sorbet, Lime sorbet or Snow white
* KEF reserves the right, in line with continuing research and development, to amend or change specifications. E&OE.
Gloss white Gloss black
Garnet Sapphire Grigio
Racing red Racing blue Pale gold
Orange sorbet Graphite Stardust
Lemon sorbet Lime sorbet Snow white