British loudspeaker manufacturer KEF was founded in 1961 by electrical engineer Raymond Cooke in a Nissen hut on the premises of a metal working operation called Kent Engineering & Foundry (hence KEF), on the banks of the River Medway, near Maidstone in Kent. Specialising in creating High-end audio, KEF is known for its innovative engineering, design and use of materials.
In its first year, KEF was planning loudspeakers of a three-way design with bass and midrange units using foil-stiffened, vacuum-formed, expanded polystyrene diaphragms with a PET film tweeter. This idea was manifested in the K1, an immediate success, followed by the bookshelf model, Celeste, a loudspeaker with an even more significant commercial success and one that helped secure the early financial stability of the new company. Re-establishing a previous relationship with the BBC in 1966, Cooke was interested in adopting another material, Neoprene (an artificial rubber) to help maintain sound quality in the mid-band by using it as the surround to the loudspeaker diaphragm, while using new materials for the diaphragm itself. Cooke was always looking for new materials at this time and, in fact, settled on Bextrene as a solution, as its lightweight plastic sheet-like properties were flexible enough for shaping and the material remained stable under varying temperature and moisture conditions and was smooth and consistent over a wide bandwidth.
As a result, in 1967, two new drive units, the 5" B110 and 8" B200 appeared which, with their many applications, found use in some 3 million units from KEF and many other loudspeaker brands throughout the world. A new, smaller tweeter also arrived, the T27,of which some 2 million units were sold world-wide. Selected combinations of the B110 and T27 were used in the most famous BBC design, the LS3/5a Monitor Loudspeaker, which was sold worldwide primarily under the 'Rogers' brand name, but has also been manufactured under the 'Chartwell, 'Audiomaster', 'Harbeth' and 'Spendor' brands . Some pundits still consider the LS3/5a' with its KEF Drive units, to be a reference in small loudspeakers.
During the 1960s KEF flourished. Loudspeakers such as the Concord, Concerto and Cresta and then, in 1969, the Chorale began to shape the company's growing reputation as loudspeaker engineers.
By 1973 the company was evolving the concept of computer-assisted "total system design", at a time when the world's very first 4-bit microprocessor was still in its infancy. KEF engineers, using a given set of parameters, could for the first time actually "see" what the response characteristics of a loudspeaker system would be. KEF was the first loudspeaker company in the world to take the new technology available seriously in order to achieve this. Now it was the use of computers and digital test methods which provided the KEF engineers with the relevant crossover and drive unit data, thus improving KEF's ability to produce accurate loudspeakers. Amongst other benefits, KEF loudspeakers could now be computer matched as an almost identical pair - to within one-half of a dB.
1973 then saw the introduction of the first KEF Reference Series Model, the 104. The 'domestic monitor' 104 provided the standards of a broadcast monitor loudspeaker in a domestic package, probably for the first time.
With the installation of a Hewlett Packard computer at the Maidstone Head Office in 1975, the Corelli, Calinda, and Cantata were all designed under the total system concept.
But 1977 saw the most radical KEF design yet in the Model 105 which apart from setting new standards for flat frequency response introduced a design by which the mid and treble were split from the bass box and placed within a contoured moulded enclosure above the bass enclosure. The added ability to angle the separate head unit provided the opportunity for the user to tailor the 105 to his or her own environment.
Ten years of growth world-wide followed, peaking with an entry into the lucrative US market in 1985 with the setting up of KEF Electronics of America. 1986 saw more activity amongst the KEF Reference Series; the 104/2, launched in 1984, spawned the 107, in reality an evolution of the 105/2 but with KEF's coupled-cavity bass loading, a system which positions the drivers internal to the enclosure, each separately loaded and firing into a third common chamber which delivers accurate bass to the listening area via a substantial front-mounted port. This combines the precise sound of a sealed box with the sensitivity of a reflex design and boosts bass performance. Also came the 102 and the 103/2 monitors. Meanwhile in the UK, the Coda III bookshelf speakers earned high praise from the audio publications, and sold well at around £110 per pair.
As well as the coupled-cavity bass loading system, KEF Reference loudspeakers featured a conjugate load network technique, which simplifies loudspeaker design from the amplifier's perspective and a heavily damped midrange module which preserves low coloration and fine stereo. A Force Cancelling Rod, fitted between the vertically opposed bass units was an added introduction, eliminating the possibility for coloration caused by woofer vibrations exciting the enclosure panels.
1988 also saw the introduction of the KEF Custom Installation speakers, in response to new world market demands. These included the CR200F and its sub-bass partner, the CR250SW.
Then, again in 1988, came Uni-Q, a single point source. The HF units used a rare-earth magnet material, Neodymium/Iron/Boron, which was developed for the NASA Space Programme. 10 times more powerful than a conventional loudspeaker magnet, this material allowed KEF engineers to make a tweeter small enough to fit within the bass unit coil former at the precise acoustic centre of the cone. KEF's Uni-Q technology delivered well-defined stereo imaging over a much wider listening area without the need for the time honoured "sweet-spot" in the listening room. The 105/3 combined the Uni-Q (now in its second generation) with KEF's coupled-cavity bass loading, conjugate load matching, force cancelling rod, computer matched crossovers and drive units, even hand pair-matched veneer finishes in one product.
KEF Audio came under new ownership in 1992. In 1994 and 1995 the company brought out the Q Series, with a third generation Uni-Q driver in a shielded format for AV use, together with the Model 100 Centre Speaker, the Model 90, the new Model 200C and the Reference Series Models One, Two, Three and Four. KEF also introduced the new entry level Home Theatre System.
At the end of 1994 the company launched three loudspeakers called Coda, including the baby Coda 7, the slightly larger Coda 8, and the floorstanding Coda 9. The Coda 9 has an extra bass driver, situated in a sealed enclosure at the bottom of the cabinet, to handle the lowest frequencies.
KEF's founding father, Raymond Cooke, died in 1996.
That year saw the fourth-generation Uni-Q driver.
The home theatre series boomed and the company introduced Model 20B, a baby brother for the Model 30B active sub-woofer.
Still occupying the same river-bank headquarters site in Kent(although the Nissen Hut no longer stands), the company exports worldwide. The company retains its Uni-Q Drivers, Ferrofluid Cooled Tweeters, Rubber Isolated Decoupled Driver Mountings, Long Throw Bass Drivers, Oxygen Free Internal Wiring, Gold Plated Bi-Wire Terminals, Computer Matching and Home Theatre Systems and hand-assembled loudspeakers. KEF has now launched its latest reference series. Its 201/2 standmount has been hailed as the ultimate bookshelf speaker.