KEF LS50 Wireless
FOR Impressive clarity; excellent build; neat package AGAINST Some minor usability issues
Imagine a pair of active speakers with preamp functionality, including digital and analogue inputs, Bluetooth and streaming services such as Tidal built in. Now you have that in mind, wouldn't it also be nice to include a streamer to replay music stored on a NAS unit or computer connected to your home network?
Such well-equipped active speakers would not only get rid of the clutter of traditional hi-fi, but could potentially deliver a performance broadly equivalent to a similarly priced separates rig. The good news is that such a product does now exist – in the form of KEF’S LS50 Wireless.
Not fully wireless
These are two fully active speaker boxes, arranged in master and slave configuration. All sources connect to the right (master) speaker, which is then linked to the left by means of a supplied ethernet cable.
As is usually the case, wireless doesn’t actually mean wireless. There are two mains leads – one for each speaker – and the connecting lead between them. Still, it's a neater solution than traditional separates.
It should come as no surprise that the Award-winning passive LS50S are the basis for this design, with the drive units remaining unchanged. The LS50S use a Uni-q array with the 25mm aluminium dome tweeter in the middle of a 13cm magnesiumaluminium mid/bass cone.
This arrangement helps to produce an even dispersion of sound and improves integration between the two drivers. What looks like a grille in front of the tweeter is in fact a waveguide that improves its performance.
That beautifully built and finished enclosure is the same as the passive version too bar a couple of centimetres of additional depth to accommodate the electronics and heatsinking. There are three cabinet options: the Titanium of our review samples, gloss black and gloss white – each option coming with a contrasting colour on the UNIQ driver array.
That unusual-looking curved front panel is made of Dough Moulding Compound, a polyester resin combined with glass fibre and calcium carbonate, chosen for its inertness and flexibility. The rest of the enclosure is made from MDF. It’s heavily braced and strongly damped to minimise any resonances. The port here is flexible in a bid to reduce distortion.
These are true active speakers where each drive unit has a dedicated power amplifier. A 30W Class A/B circuit feeds the tweeter while a 200W Class D module powers the mid/bass unit. The Class D design was chosen for its combination of high power and low heat output.
KEF has taken advantage of the internal DSP by phase correcting the crossover and using the software to allow the speakers to play loud and true while minimising distortion. The digital signal path is 24-bit/192khz capable and there’s a dedicated DAC for each drive unit. Only the optical input is limited to 96khz signals, but that’s not unusual.
At the back of the right speaker you’ll find stereo analogue, optical and USB Type B connectors. There’s also a subwoofer connection, in case you want to add more low frequency output, and an ethernet socket for connecting to your network.
Normally we’d recommend sticking to the wired network option for greater stability, but we use the twin-band (2.4ghz/5ghz) wireless option for most of our test without issue.
There are also controls for adjusting the sound for different speaker placements with options for close-to-wall or free space positioning as well as the choice between desk or stand supports.
The ios/android app looks nice, is well laid out and easy to use. It controls the streaming (DLNA as well as Tidal) functionality and allows plenty of scope to fine-tune the speaker’s performance in a given environment. There is room for improvement, though. It’s a little glitchy and feels unresponsive at times.
Digging up detail
The sliding volume control doesn’t change the volume until you lift your finger, so you don’t know how loud it’s going to be until you hear it. It can be a shock. It’s important to note that the app doesn’t switch between physical inputs, as it operates the KEFS only in streaming mode. To change inputs, you need to use the supplied remote or the touch controls on the master speaker. This swapping around of controllers is annoying if you switch sources a lot, particularly as the app has to reconnect with the LS50S every time you switch back. It would also be nice to see an indication of the input chosen when sitting at the listening position – the only indicator is out of sight on the right
speaker’s top panel. So if you’re using the remote to change input there’s no way (apart from counting clicks) to know what input the LS50 has settled on. None of these things is serious enough to be a deal breaker, but they make using the speakers a fussier experience than it should be.
We start off with Arvo Pärt’s Tabula Rasa and are deeply impressed by what we hear. The LS50 Wirelesses sound clean and precise, digging up detail and delivering it in an organised and stable manner. We’re struck by the KEFS’ ability to generate strong dynamic shifts without stress. To our ears they sound at least as good as the best comparably featured separates combinations available for similar money.
These are small speakers but they manage to fill our medium-sized listening room with high volume levels. KEF claims a maximum sound pressure level of 106db, which should be loud enough for most people in most circumstances.
Positioned with care, a little away from the rear wall and with a touch of toe-in towards the listening position, they render a lovely, expansive soundstage that’s neatly layered and nicely defined. Even with the LS50S in less optimised positions, the app makes the results sound balanced.
Moving on to Massive Attack’s Angel shows the LS50S’ impressive bass performance. These aren’t big speakers so you won’t get floor-shaking bass, but they generate low frequencies that are taut, articulate and punchy. For a speaker that stands 30cm tall and has a mid/bass unit that’s just 13cm in diameter, it’s impressive. The good news continues higher up the range with a transparent and fluid midrange and insightful highs. Vocals are delivered with passion while percussion comes through with bite and composure.
Broad range of talents
Overall, these speakers have the insight to unravel a recording yet never tear the music apart. They’re informative, but musical too.
We play a range of music from the heartfelt grit of Bruce Springsteen’s Terry’s
Song and sparse electronica of xx’s Stars through to large scale symphonies by Stravinsky and Beethoven. These speakers take it all in stride – and it takes a broad range of talents for this to happen.
KEF has done a terrific job in taking the Award-winning LS50S and making them an even better proposition. That £2000 price tag looks hefty for such compact speakers, but remember: that money also buys you a dedicated streamer, a Bluetooth module, 24-bit/192khz DAC, preamp and four power amplifiers with a total of 460W of output. Is this what the hi-fi system of the future should look like? We certainly hope so.
“To our ears, these KEFS sound at least as good as the best comparably featured separates combinations available for similar money”
The connections, including one for a subwoofer, are on the right speaker
They might be small speakers, but the KEFS have a maximum sound level of 106db