|Founders||Raymond Cooke OBE|
|Products||Studio monitors, Loudspeakers, Loudspeaker Drivers Subwoofers, iPod Speakers|
|Owners||GP Acoustics Ltd|
KEF is a British-based loudspeaker manufacturer with international distribution. It was founded in Tovil, Maidstone, Kent in 1961 by electrical engineer Raymond Cooke and named after Kent Engineering & Foundry which previously occupied the site. Its founder, Raymond Cooke, was created OBE by Elizabeth II in 1979.
KEF is now owned by GP Acoustics, which is itself a member of the Hong Kong based Gold Peak Group. Product development, acoustical technology research and the manufacture of flagship products still occurs on the original Tovil site in England.
Raymond Cooke with his business colleagues founded KEF Electronics Ltd., with a view to creating innovative loudspeakers using the latest in materials technology. The company was founded in Kent in 1961 on the former site of Kent Engineering & Foundry, from whom KEF derived its name.
Cooke was a Royal Navy WWII veteran who was a design engineer at the BBC for a year. He was later Technical Director at Wharfedale, then a leading British loudspeaker manufacturer. Following corporate change at Wharfedale, Cooke left to see his own ideas put into action. Cook acquired the site of a foundry, makers of agricultural machines, and initially worked in Nissen huts erected on the site in Tovil, Maidstone. In KEF: 50 Years of Innovation in Sound, the authors assert that KEF reduced the average size of bass-rich home loudspeakers from 9–10 cubic feet (250–280 l) to about 2 cubic feet (57 l), based on the work on the "acoustic-suspension woofer" at Acoustic Research; the company pioneered large-scale production of drivers with cones made of materials other than paper, and the application of fast Fourier transform analysis to the measuring of loudspeakers. KEF was also an early-adopter of modern quality-control principles to driver manufacture.
The first loudspeaker manufactured was the K1 Slimline for which the drive units used diaphragms made of polystyrene and melinex. Soon after, in 1962, came the famous B139 'racetrack' shaped woofer which allowed the design of the Celeste – one of the first truly high performance bookshelf loudspeakers. As Laurie Fincham, Cooke's successor as chief engineer, later revealed, the only reason the B139 was vertically mounted ovoid-shaped was that the British tax code at the time penalised products above a certain arbitrary width.
BBC monitors and beyond
From the mid-1960s, KEF manufactured BBC-designed monitor loudspeakers such as the LS5/1A for the Corporation and for wider distribution. Cooke's previous relationship with the BBC in the 1950s continued as KEF developed through the 1960s and 70s. In the mid-1960s KEF introduced the bextrene-coned B110 bass/midrange unit and the melinex-domed T27 tweeter which were later used in the diminutive BBC-designed LS3/5A broadcast monitor, of which over 50,000 pairs were sold worldwide and whose initial specification was for use in cramped broadcast vans. The close co-operation between KEF and the BBC Research department was fruitful for both, as BBC provided stringent performance and production standards with ample capacity for field testing, with KEF being a pioneer in the use of polymers and computerised quality control.
In the 1970s, as "KEF Electronics Limited", the company was awarded two Queens Awards for Export Achievement (1970 and 1975). This further substantiated Raymond Cooke's choice of location for his factory as it "was closer to Europe" and hence transportation costs for its goods would be cheaper.
In addition to making speakers, a substantial part of KEF's activity was as an OEM supplier of loudspeaker systems, baffles and drivers. Cooke decided early on that huge potential benefits could be reaped from selling raw drivers to competitors, that more than outweighed the cannibalisation of their own market position. In a relatively short time, many major and renowned loudspeaker manufacturers came to source their drive units from KEF. Users included illustrious British brands such as IMF, Rogers, Celef, Monitor Audio, as well as manufacturers outside UK, including Sonus Faber and Wilson Audio. Linn Products of Scotland also elected to use KEF drive units in the Linn Isobarik., Linn Sara and Linn Kan speakers. The company's KEFKITs also provided many hi-fi hobbyists with means to apply their woodworking skills into making their own speakers. At its peak, production of drive units reached 10,000 units per week. In 1979, Queen Elizabeth II awarded Cooke an OBE.
KEF lost its direction after making its last batch of BBC-licensed monitors, and eventually went into receivership. It was acquired by GP Acoustics, a member of the Hong Kong based Gold Peak Group. Product development, acoustical technology research and the manufacture of flagship products has been revitalised, and still occurs on the original Tovil site.
In the early 1970s KEF was the first company to adopt computers for the testing and design of loudspeakers leading to the 'Total System Design' methodology and more sophisticated production techniques such as driver 'pair matching'. The radical Model 105 system, released in 1977, embodied this new philosophy and was one of the most highly regarded loudspeakers of its time. KEF, Bowers & Wilkins and Celestion were the "big three" British loudspeaker makers of the seventies and eighties, and pioneered the use of advanced materials and techniques in audio.
Other technologies developed and brought to the market by KEF have included:
- driver decoupling (Model 105.2, 1979), a technique of reducing cabinet coloration by mounting drivers via controlled lossy coupling
- coupled-cavity bass loading (Model 104/2, 1984), a technique of pairing two bass drive units and feeding their output via a single port
- conjugate load matching (Model 104/2, 1984), a crossover optimisation technique that presents a constant (albeit low) ohmic load to the amplifier
- the "KEF Universal Bass Equaliser" (aka "KUBE") (Model 107, 1986), a technique to overcome the unavoidable phase lag present at low frequencies
- Uni-Q (C-Series, 1988), a patented implementation of coincident midrange and tweeter drivers that strives to preserve phase integrity and match dispersion between the drivers resulting in improved stereo imagery
- Marks, John (10 February 2012). "Book Review: KEF: 50 Years of Innovation in Sound", Stereophile.
- "A History of Kef Drive Units from the 1960s and 70s". KEF Electronics.
- "Iconic Hi-fi' Audio Milestones: Linn Isobarik" Hi-Fi News, November 2011 (courtesy link)
- KEFKITS. KEF Electronics (leaflet no. KK/3 GA6802/20M/4.75)
- Fantel, Hans (3 February 1991). "Said a Speaker To a Living Room: 'Speak to Me'". The New York Times. Retrieved 23 March 2009.
- L.R.Fincham and R.V.Leedham. 'Loudspeaker evaluation using digital fourier analysis'. Presented to the British section of the Audio Engineering Society, London, February 1973
- KEF Muon
- KEF Blade
- KEF Reference Series
- KEF R Series
- KEF Q Series
- KEF LS50
- Uni-Q Technology
- Wireless Speaker Technology