KEF Turns 50: A Retrospective

Posted by: Alan Sircom at 4:04 pm, September 23rd, 2011

 The name KEF perhaps perfectly encapsulates founder Raymond Cooke’s no-nonsense approach to making things. In 1961, engineer Cooke needed a factory to build loudspeakers, and the place he settled upon was the site of the former Kent Engineering & Foundry company in Tovil, Maidstone, Kent, in the UK. Rather than change the name, Cooke decided to call his new company “KEF.”

Raymond Cooke OBE (1925–95) was an engineer’s engineer. Starting his career as an industrial chemist with one of the main railroad companies in the UK, he joined the Royal Navy and spent WWII as a radio operator. Following the war, he was awarded a degree in electrical engineering and worked for the British Broadcasting Company’s then-prestigious Engineering Department, working under Dudley Harwood (later of Harbeth fame). Around this time, he met Gilbert Briggs of Wharfedale, helped edit Briggs’ books, and in 1956 became Wharfedale’s Technical Manager. It was there he discovered that the current thinking at the time, which held that deep bass needs large drivers, was not the only way. Cooke experimented at Wharfedale and found that lower efficiency and smaller drive units could deliver accurate deep bass, too. He was also convinced that improved performance was only possible using the latest in materials technology—in other words, drivers that featured diaphragms made of plastic instead of the near-universal paper cones found at the time.

When Wharfedale was sold to the Rank Organisation in the late 1950s, Cooke decided it was time to go it alone. He couldn’t have picked a better moment, since the shift from mono to stereo was becoming a hot topic among hi-fi enthusiasts, in turn creating demand for pairs of smaller, more accurate loudspeakers. KEF rose to the challenge with its first loudspeaker, the K1, which was a comparatively small three-way design, bristling with then-state-of-the-art technology, including foil-stiffened, vacuum-formed polystyrene diaphragms and a tweeter with a diaphragm made of Melinex (Mylar). This was at a time when almost every other loudspeaker had a doped-paper bass cone and, at best, a fabric tweeter.

Buoyed by the K1’s reception, by the mid-1960s, KEF used what it learned to deliver the Celeste, one of the first small high-performance loudspeakers ever seen in the UK. With the more powerful transistorized amplifiers beginning to appear, KEF’s use of new materials gained in popularity, and a pair of small KEF Celestes proved hard to better at the time.

During this same period in the UK, there was a still strong contingent of amateur loudspeaker builders who preferred to make rather than buy fully finished speakers. Among those builders, KEF enjoyed a commanding reputation as a drive-unit maker whose ever-growing portfolio of speaker drivers were known for their advanced designs and materials technologies. With sales running into the millions, KEF became the premier supplier of next-generation loudspeaker drive units, and that attracted the attention of Cooke’s old teammates at the BBC. Among the successes at the time, KEF’s ¾” Mylar T117 tweeter and 5” Bextrene B110 mid/bass cone driver, proved immensely popular both in the 1967 Cresta loudspeaker and with DIY’ers. They also formed the core of the BBC LS3/5 and—in later form—the legendry LS3/5a. In fact, KEF’s association with the BBC lasted from the 1960s until the broadcaster’s Engineering Department effectively closed in the 1990s.

From the outset, KEF established itself as a science-led company, and in the 1970s KEF was at the forefront of development in computer design, modeling, and acoustic research. The company was pivotal in the development of measuring loudspeaker frequency response using computerized Fast-Fourier Transform techniques. The company developed what it called a “total system design” structure, using digital techniques at a time when “digital” meant “counting on your fingers” for most people. This meant pair-matching drive units in loudspeakers to within half a decibel, therefore making far superior stereo imaging than most contemporaneous speakers. KEF developed the Corelli, Cantata, and Calinda ranges at this time.