Factory visit loudspeaker manufacturer KEF: This is the cradle

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KEF is one of the most popular loudspeaker brands in audiophiles. That has to do with the excellent performance of speakers such as the Reference series and Blade, which were developed using the latest computer techniques. That more technical approach is just typical of the British. We went to the cradle, in Maidstone, to discover what makes KEF exactly KEF.

Factory visit KEF

“We cherish our history”, says brand ambassador Johan Coorg at the start of our tour of the KEF buildings . You can immediately see that on the buildings, which are still standing on the sites where it all started in 1961. A former BBC engineer, Raymond Cooke, then decided to build speakers based on the most advanced materials available at the time. This more scientific approach was unique at that time.

At that time it was still an industrial area, now KEF is in the middle of the residential areas of Maidstone, a town in the British county of Kent. So in those 57 years a lot has changed around KEF and at the company itself, but it remains true to its roots. And those roots are designed and built better in a well-thought-out, well-founded way. “And by listening, because that remains important when you think of a loudspeaker,” it says. Our guide is Johan Coorg, someone who knows a lot of Dutch hi-fi enthusiasts. For years he has been the flamboyant face of KEF on product presentations and hi-fi shows throughout the Benelux. Strikingly, he is a Briton, but thanks to his family background and a language knot, Coorg speaks Dutch fluently. You do not often see that. He is assisted by Jack Oclee-Brown, a younger engineer who comes across as calm and thoughtful as Coorg is exuberant and enthusiastic. A great duo.

From museum to now

The buildings in Maidstone are fully equipped for research and development. There is also a piece of production, but only of the hand-built high-end loudspeaker lines: the Reference-speakers, the Blade and Blade 2, and the overwhelming, 2-meter high Muon. KEF has been part of GP Acoustics for more than 25 years, which in turn is part of the Gold Peak group from Hong Kong. The initial fear that the KEF brand would end up with all kinds of inappropriate products – as often happens – turned out to be unfounded. The Chinese holding company treats the British brand with great respect and also wants it to remain true to its character. Meanwhile, investments have been made in a very expensive production center in South China, where 1,500 people work. “We are so much bigger than before, it simply can not be any different”, says Coorg. But the beating heart remains in Maidstone.

Whatever we find in the buildings in the British town: the KEF museum. Nearly all the loudspeakers that the company has ever built are located here. You can safely call this a small miracle, because a few years ago the river flooded next to the company and the museum stood – literally – with the water up to the lips. This caused some historically important speakers to be damaged, but fortunately the collection is now almost complete. You will see the first reference speakers and models linked to the famous ‘BBC’ LS3 / 5 speaker for which KEF designed drivers. This speaker was built for the BBC and manufactured by different manufacturers under license, primarily by brands other than KEF (such as Harbeth and Spendor). In the end, KEF also released its own version, in addition to derivatives such as the Cresta and Coda. The BBC speaker is a piece of history that still resonates, because it was the inspiration for the popular LS50 that appeared in 2011 and even more recently for the award-winning LS50 Wireless. Immediately a completely new direction for KEF. “Yes, the LS50 Wireless is our first fully active speaker with streaming. But it is above all a complete platform, which we can also use in future products “, says Coorg. Unfortunately, we did not see any traces. “No, everything that is not yet known, we have hidden. And we do not go to the building with our ‘skunkworks’, where there are some engineers working on very early ideas. ”

Blade is the example

” The Blade is a good example of what makes KEF special. It is that combination of industrial design with a good loudspeaker. It must sound good, but you also have to be able to live with it. But there is something unique, “says the brand ambassador. “Our products are very consistent in tone. So you can combine our built-in speakers in your home with, for example, Reference speakers – and they fit together. ”

That has to do with the great invention of KEF: the Uni-Q-driver, very recognizable with its waveguide reminiscent of the inside of a grapefruit. It is a so-called coaxial driver: a woofer with the tweeter suspended independently in the middle. The big advantage is that sound seems to come from one point. That is much more natural than with a speaker where the frequencies of an instrument are divided over different drivers. Coorg explains it very expressly. “Imagine that you spoke to someone with two mouths. One on his chin and one on his forehead. That would sound damn weird, would not it? ”

Uni-Q is undoubtedly a big innovation in hi-fi, something we always notice when reviewing KEF speakers. One nice advantage, for example, is that speakers such as the LS50 are very coherent from up close. Near-field they sound just as good as far away. The sweet spot is also very wide.

KEF also continues to work on Uni-Q, so this driver evolves even further. “The best Uni-Q is in the Blade. Quite difficult because it sounded better than the driver in the Muon. That is why there is now a mk.2 from Muon. Of course we can not leave the first owners of these 180,000-euro speakers in the cold. That is why we are prepared to fly an engineer to any place to replace that driver. ”

According to Coorg, everything KEF has to do with the Blade today. “We had some journalists on the line who noticed that the R-series contains the same Uni-Q as the Blade. Whether we were insane, it always sounds. But there are differences, for example in terms of the engine system. ”

Faster and better development

” Thanks to the computer, we can try out hundreds of versions of a component and even test out insane ideas without building anything real. Ultimately, when we start to produce something physically, we already have designs that are completely elaborated and refined “, we hear from acoustic engineer Christopher Spear. And that goes pretty far. For example, he shows us how the design team investigated through simulations how a small part of the Uni-Q waveguide could be optimized. Adjustments to the shape and a different material can have an effect on the sound, and that can all be seen through advanced software. “The tweeter you now see on the screen is made out of aluminum”, it sounds, “but with the press of a button we make cork or titanium.” Working in this way is cost-effective, because unlike in the past fewer models or prototypes are being built. “But it makes us decide faster to exclude certain directions or to investigate further. We can make thicker or thinner in software parts or heavier or lighter, and immediately see what works better. ”

This way of working is quite revolutionary. KEF is certainly not the only manufacturer that tries to design better drivers and speakers via simulations, but few have the power to invest heavily in computer design. That gives the brand a serious advantage. “It is also groundbreaking. Fifteen years ago we could not have done this yet “, Jack Oclee-Brown remarks. “If we then had six months to make a new tweeter design, we lost a lot of time building models and testing. Computers were also not fast enough. Now you can refine your designs very quickly. ”

A detailed model on a computer is one thing, but a finished speaker is something else. To make this possible, KEF employs specialized engineers who think about how the simulated parts can actually be made. “We also have to take into account the input of the industrial design team, which ensures that the speakers look good,” explains one of the team members, Bill. “We used to work with paper, which we did. But it was 2D drawings that we sent to a machine builder, who in turn interpreted the drawings and constructed the necessary tools (such as a template or template). What you received did not look and sound as you had expected. That is now much faster and better. We receive the data from the acoustic and design teams, and make a model in CAD / CAM software. Previously, we had to wait weeks for a prototype part, now it takes a few days for a 3D printer office to do the same. ”

Total control

A small highlight of the day were a few demos in the home cinema of KEF. It is a room where every KEF speaker is listened to, controlled by electronics from Arcam and Oppo. We listen to a 7.2.4 set-up that comes across as particularly well-balanced, in particular, with a layer that integrates excellently. “This room is also made for training and product development. We can listen to three 8-channel systems side by side here. Ideal for comparison and benchmarking. ” But what probably made the most impression during our visit to KEF – in addition to the fascinating explanation of Oclee-Brown and his team – were the listening sessions with the Blade 2 and the Muon. The latter is of course totally out of category. Impressive, yes, but also unreachable for almost everyone who reads this article. That is different with the Blade and Blade 2. They are not cheap, but they are feasible for those who love music seriously.

The Blade we just listen to back home just before our departure is a bright green specimen, but the unusual color does not detract from the great controlled and balanced view. A must to go and have a look if they are in a hifi shop in the neighborhood make their appearance at a show.

What we take especially after a full day in Maidstone is a stronger feeling that loudspeaker builders from the highest class can not work differently than KEF. Scientifically supported, with a great deal of research in advance, through simulations refined in detail, with a lot of testing, and with a strong cooperation between development, design and production. That is the future of hi-fi.