KEF LS50 loudspeakers, a bow to the past and a nod to the future (part 1)
Any company in any field that can claim 50 years in business is doing something right. But the UK’s KEF has a vibrant history both in terms of their own finished speakers and the products that the fruits of their research made possible. The drivers that KEF designed back in the day were classic and many of the speakers that employed them are enjoyed in homes to this day. BBC researchers, who designed monitors without commercial intentions but only to provide as faithful as possible monitoring of their transmitted signals, used KEF’s drivers liberally, most notably in the LS3/5A.
If all the KEF drivers inspired were the legendary LS3/5A, they would hold an honored position in audio history. But many other classics used the B-110 and T-27 and the other KEF designs. In addition to numerous KEF designs, the Linn Kan and Isobarik, JR- 149, various IMF’s and TDL’s, various Celef’s, various Tangent’s, early Meridian, ProAc and Monitor Audio’s, employed KEF drivers.
Now 50 years later we have the LS50 where the “LS” is a nod to KEF’s BBC legacy. But that’s pretty much where the similarity ends. While they do still employ KEF designed drivers, the drivers are nothing like the Bextrene coned units of yesteryear. KEF calls the new drivers “Uni-Q”, and they are a concentric design with the tweeter mounted in the middle of the driver where the dustcap would be in normal drivers. The concept of a concentric driver actually goes way back to the old Tannoy drive units from the late ’40’s, but KEF started their investigation into their technology in the mid ’80’s with the benefit of modern technology and materials. The first KEF speaker to employ the Uni-Q was introduced in 1988 and the driver has evolved quite a bit since then.
The latest versions of the Uni-Q were produced for the “Blade” project, which finally saw the light of day as a commercial product in 2011. The Blade is an excellent design, but sells for $30,000. I was going to say “unfortunately sells for $30,000”, but when you consider what flagship speaker designs from established (and non-established!) companies sells for these days, the $30,000 almost seems reasonable…
So when the LS50 was announced, the first thought prompted by its looks was “mini-Blade”. I am not sure it’s quite that, but it does seem apparent that it benefitted from the Blade’s research in its design. I also think it looks pretty cool, the piano black, curvaceous cabinet and Rose-Copper colored concentric driver making a nice looking modern style package, in my view (though it might not go with your Chippendale sofa and Tudor balustrades). So this looked like a likely prospect for my small speaker project.
My first move upon obtaining a pair was to deploy them in my bedroom system for break-in. In the bedroom I mostly listen to FM radio through a small Job Amplifier, itself an intriguing Swiss design that inspired some of the later Goldmund amplifier designs (unfortunately, the Job is discontinued now).
First listens were intriguing, the announcers voices on my local Classical music station (WWFM) sounded quite natural without excessive chestiness. It was interesting to me that LS50 tonality was good enough to let me guess that an unfamiliar piece of music (it turned out to be Adventures in a Perambulator by John Alden Carpenter) was a Mercury Living Presence recording and a Beethoven 7th was a Deutsche Grammophon (Carlos Kleiber). So far so good!
But the two things that struck me right away were the speakers disappearing act and the low-level of cabinet coloration. The imaging, even under the less than optimum conditions they were operating under, was quite fine. And there was this sense of purity, as though you were hearing the driver talking for itself without influence of the cabinet. Now this might be expected from a small speaker with a highly engineered cabinet, but it’s unusual to hear none the less.
Part two will give further impressions after break-in and in my main system. Stay tuned.