KEF Cuts The Cord On The LS50

KEF has been building speakers featuring their famous “Uni-Q” concentric driver for decades, but it was the LS50 monitor first introduced a few years ago to celebrate the company’s 50th anniversary that really gained them widespread attention outside of the traditional high-end speaker market. The LS50, supposedly “inspired” by the classic BBC LS3/5 monitor, is anything but old fashioned. A wooden box was eschewed in favor of a state of the art cabinet design with a curved baffle designed to control both external resonance and internal standing waves as much as possible, thanks to the help of Finite Element Analysis, Boundary Element Analysis, and Computational Fluid Dynamics. Sitting right in the middle is an orange colored concentric driver, with KEF’s unique central waveguide and specially designed woofer cone to provide optimal dispersion.

One thing the LS50 does have in common with the LS3/5 is that it was designed to be equally at home sitting on top of a mixing console or on stands in a living room, but the lack of an active version made it somewhat of a tough sell against PMCs or ATCs. Until recently, if you wanted something like the LS50 but with an internal amp, you had to get the X300A, a speaker that, while certainly no slouch, is not in the same class with the LS50 in either design or performance.

Fortunately, KEF has finally remedied this omission with the new LS50 Wireless. KEF could’ve simply slapped a plate amp on the back of the LS50 for the active version and called it a day, but they went a lot further than that. Starting with the amps, each LS50 Wireless speaker packs two of them, one for the woofer and one for the tweeter, with an active DSP controlled crossover divvying up the frequencies. This isn’t unusual with higher-end active monitors, but what is unusual is using two different amplifier topologies to power one speaker. KEF wanted a lot of power for the woofer, and with very little space available, by far the easiest way to do that is via a Class D amp module, which in the LS50 Wireless packs a healthy 200 watts. Where Class D designs are typically weaker than linear A/B amps are in the highs, and so the LS50 Wireless uses a 30 watt Class A/B amp to drive each tweeter. Very clever.

The LS50 Wireless also packs a built-in DAC with optical and asynchronous USB inputs, and if those weren’t enough, it will also accept streaming Wi-Fi and AptX Bluetooth. Did I mention all of this stuff is controllable via an app on your phone, along with the ability to control a connected subwoofer, adjust boundary compensation, and treble level? And there’s a remote too. The price is of course up compared to the passive LS50, but surprisingly not that much considering all the regular LS50 has on its rear panel is a pair of binding posts. An extra $700, or $2200 for the pair, adds all of the above. Granted that’s quite expensive for a pair of monitors, but these monitors allow you to cut out the entire rest of your system. You can connect a phone, and you’re done. They are set to be released next month, and hopefully we can get our hands on a pair. Stay tuned.