KEF LS50 Wireless II Streaming System Review

The KEF LS50 Wireless II is the second generation of active LS50. When KEF released the original LS50, it did so as a passive design (and very good it was too). The company then proceeded to surprise quite a few people (myself included) with an active version. The surprise was twofold. Firstly, with the honourable exception of its subwoofer range and the curious - but rather good - Egg Digital Music System, KEF has largely focused on passive speakers. For the firm to go active after many decades of happily not doing so was a surprise.

In many ways, what was more surprising was how KEF had made the LS50 active. Rather than go the traditional way of applying amps to speakers; attach/integrate the amp and power supply and leave control to somebody else, via either RCA or XLR, KEF turned the LS50 into a system. It became a device that needed only an internet signal to be a fully functional device in its own right. As decisions go, it was a good one because KEF has sold a great many of them.

Now, with the passive LS50 getting an update, the active version has too. In some ways, these are more significant than the passive version. This is because, bold and innovative though the LS50 Wireless was, it had some operational quirks that meant it couldn’t always deliver on the promise that the specification had. Can this considered rework get the job done and turn the Wireless II into a fully fledged Atom smasher?

As I have been able to write a full and considered review of the passive LS50 Meta, in which I have had the space to go into the driver revisions in some depth, I will not repeat them here. Every improvement that has been made to the passive LS50 is replicated on the active one and they reflect KEF’s near fanatical attention to detail when it comes to the business of driver and cabinet behaviour.

Whereas the 150mm driver in the passive Meta makes demands (and considerable demands too) on an external amplifier, the Wireless II brings that power on board and quite a bit of power too. My comments in the passive review that the LS50 benefits from a bit of driving might benefit from the framing that each wireless version has no less than 380 watts of power. This is split with 100 watts allocated to the tweeter and 280 to the mid bass.

The crossover of the LS50 Wireless is tied up with a piece of software that KEF calls the Music Integrity Engine. As well as splitting frequencies between the drivers, it ensures that time alignment (something that the Uni-Q already has a fairly decent head start on) is dynamically adjusted to suit and additionally allows for user adjustment to suit placement relative to walls. Its inclusion is a reflection that this is not simply a like for like take on the LS50 Meta but with an amplifier, but instead something that has the flexibility to ‘dial in’ to spaces that the passive version might struggle with.

As befits a device that is designed to be used as a standalone system, the connectivity on the KEF is extensive. It has a solitary analogue connection on a 3.5mm input but the design premise is more about the digital connectivity. The KEF is fitted with a 24/384kHz capable UPnP streamer that also handles DSD to 128 and is able to perform an MQA unpack for Tidal fans (as well as supporting Qobuz. Spotify Connect and Deezer). This is combined with a coaxial digital, optical and HDMI ARC connection as well as that analogue input. You can also wirelessly stream to the LS50 Wireless II via AirPlay II, Google CAST and Bluetooth 4.2. KEF has also ensured that they are also Roon ready.

Something that should be taken into account when deciding if the KEF is suitable for you is that, like the Q Acoustics Active 200 we looked at recently, the KEF operates as a closed pair of speakers. If you send a signal from a turntable to it, it’s going to be redigitised in order to be sent to the speaker that doesn’t have the input board on it. One of the major revisions for the Wireless II is how his transfer is done. The original LS50 Wireless would only accept a wired connection (over RJ45) between the two speakers. The LSX updated this process to work wirelessly at a locked frequency of 24/48kHz. The Wireless II makes use of the same functionality but ups the transmission resolution to 24/96 (or above that of the bulk of material that most people are going to listen to). If you want more than this, you still have the option of wiring them together.

I am pleased that the option remains because, like when I tested the LSX, wireless connection between the two speakers hasn’t been bulletproof. There must be an element of frustration for anyone involved in the project because my statement ‘hasn’t been bulletproof’ breaks down to one incident where only the master speaker came out of standby and another where connection dropped after a few hours of use. This means, in total, after roughly forty hours of listening with a wireless connection between the speakers, the amount of time where I only had one speaker running was perhaps fifteen minutes. The problem is, with a stereo product like this, you are going to notice if a channel is out and it sticks with you. If you have the means to run the speakers with their wired connection it may benefit you to do so.

One area that has made some progress though is the control app. The one (or should I say ‘ones’) for the LSX felt cobbled together and were both poor in terms of speed and stability and limited in what they could do. The Wireless II has a single app for set up and control and, while it still has some limitations reading a large NAS library (where it’s outperformed by MConnect or Kinsky), the streaming service integration is excellent, the DSP adjustment is easy and stability is very good indeed. Compared to the Uniti Atom or NAD M10, the KEF still feels a little off the pace but it is at least now in the same race. There is a remote handset that allows for instant mute if someone calls on the device you’re running the app on and this is backed up by a set of physical controls on a touchpad on the master speaker. 

The manner that this is integrated into the top of the cabinet is beautifully realised and it’s details like this that help the KEF to be genuinely user friendly. The fit and finish is every bit as good as the passive version too. Do be aware that there some unavoidable quirks of placement that the KEF can’t easily nullify though. Any HDMI or optical connection from a TV is going to have to come out to the master speaker and both of those speakers need mains power. If you can dress it correctly, a setup based around the Wireless II will look outstanding… but you’ll need to put the effort in.

What this does is highlight how much else KEF has got right with the LS50 Wireless II and that means that the KEF genuinely feels like a competitor to some of the slicker all-in-ones on the market at the moment. It also works to the aesthetic advantage of the basic design of the LS50 too. Used with a stack of electronics, the KEF can look a little incongruous. Used on either side of a TV, particularly on its own dedicated stand, it looks brilliant and more appropriate for some of the brighter colours, by which I mean, if you don’t buy them in red, you’re a coward.

The KEFs have been placed on a pair of Soundstyle Z60 stands and powered from an IsoTek Evo 3 Aquarius mains conditioner. They have been tested over the KEF app but most listening has taken place with Roon, taking a feed from a Roon Nucleus. An optical feed from an LG 55B7 OLED TV has been used for video testing while an Oppo Find X2 Neo has tested Bluetooth and an iPad Pro has been used for AirPlay work. Material used has been FLAC, AIFF, DSD plus Tidal, Qobuz and some on demand TV services.

More: Audio Formats

Listening to any speaker that is available in a passive and active configuration is generally fascinating because, subjectively, you’ll come down on one side or the other. Be under no illusions, I rate the LS50 Meta highly but it only took an hour or so to have me thinking that the Wireless II feels like the ‘correct’ application of this technology. Don’t forget that I also say this having used the passive speaker with amps like the Naim Supernait 3 (£3.5k) and Cambridge Edge A (£5.5k). I pampered the LS50 Meta but it’s active brother still has abilities that the passive version lacks.

Key amongst these is grip. Now I am aware that ‘grip’ is a subjective term; I can’t point to a moment on a measurement trace and go “that’s grip right there.” I can suggest that when you play the insanity of The Comet is Coming’s Super Zodiac on the Wireless II, it responds with unflappable resolve. This is a big and deliberately chaotic piece of music and, without losing the fury, the Wireless II unpicks it a little to make sense of everything. That same rock solid imaging and soundstage that the Uni-Q does so well is here but everything within it feels a little more ordered and controlled.

What is notable is that a combination of the DSP and the fundamentally demanding nature of the LS50’s basic design means that, even with 380 watts at its disposal, the Wireless II feels ‘about right’ rather than ‘ludicrously overpowered.’ Sure, if you wind the volume slider toward the upper registers, it will eventually sound a bit ragged but you have to push much harder than you might expect for this to happen. It also means that the bass response is phenomenal for a cabinet this size. I’ve actually found that telling the DSP that the speakers are closer to a wall than they actually are has helped. It might mean that, when scrutinised on a trace, the KEF is pulling a few hertz from the signal. In room, it means you still have prodigious low end but now possessed of unburstable composure and control.   

It also means that the KEF is a fine partner for TV viewing. They were on hand for the first episode of Loki and their natural three dimensionality saw them do wonders with the world of the Time Variance Authority. The little details that ‘build the world’ are all present and easy to discern within a space that keeps dialogue locked to the screen but allows effects to move beyond it. The simple expedient of a true stereo image is enough for the KEF to contest the market with the boxes to which you add speakers while being conceptually closer to the one box units. It’s a neat balancing act that KEF have exploited by being a company adding electronics to speakers rather than the other way around.

One other aspect of performance that has stood out over the time they have been here is that the Wireless II goes a long way to being source agnostic. Sending Deezer over AirPlay II obviously loses out to Qobuz via Roon but it never stops being listenable. The KEF manages the same consistency that Q Acoustics does with the Active 200 but, where the Q Acoustics is set up to be a room filling, positioning independent device that flatters the compressed signals, the KEF points out that they are compressed and has a smaller sweet spot but, when you open the taps and give them a decent signal, it’s the LS50 that delivers the goods.

KEF LS50 Wireless II Streaming System Review