Review: KEF Xio

There’s a level of confidence you have to admire in a brand entering a new market and out-pricing almost every single one of its competitors, straight from the off. That certainly appears to be KEF’s strategy with its very first soundbar, the KEF Xio—an all-in-one Atmos soundbar that will set you back a cool $2,500 (£2,000.)

Of course, there’s the obvious: that’s enough to buy yourself a pretty decent surround sound package, with a performance that any soundbar will struggle to match. But if you’re reading this, you’ve probably already decided against that, whether that be for space, time or patience. So what does that kind of money get you in a soundbar, and is it worth paying the premium?

“We've been talking about doing a soundbar like this for a long time,” Jack Oclee-Brown, KEF’s VP of technology, tells WIRED, “but I think the catalyst for us finally doing it has been getting to a point with some key technologies that have allowed us to reach the performance where people will sit and go, OK, this sounds like a KEF speaker.”

Some of the technologies at play here will sound familiar to anyone who knows the brand. That’s because KEF has adapted the Uni-Q drivers found in its high-end hi-fi speakers, and made them smaller—combining a tweeter dome and a midrange cone into one driver, connected by a resilient rubber link. This works like a mechanical crossover (hence the name Uni-Q “MX”) and enables the two parts to move together, while also allowing the dome to move on its own for higher frequencies.

You'll need a fairly large stand to fit the KEF Xio in its entirety.

Photograph: Verity Burns

Three of these drivers are built along the front of the bar, along with a slightly narrower version of it at each end for width and also three along the top—although how many of the latter are in use depends on the bar’s orientation.

When positioned on a stand (as we tested it), just two will be used to form the bar’s upwards-firing Atmos channels, but when wall mounted, the “top” would then face the user and that third driver becomes the center channel. KEF says the bar knows how it is positioned and will adjust its driver output accordingly.

These drivers are joined by two pairs of P185 LF drivers for the bass, which sit back-to-back in two positions along the bar. These super-slim, but high-aspect-ratio woofers use KEF’s P-Flex technology, also found in its compact KC62 and KC92 subwoofers, to create what’s known as force cancellation, reducing the mechanical vibrations created by low frequencies in such a small cabinet that can wreck the sound.

The final bit of KEF tech at play here is its patent-pending Velocity Control Technology sensor, which Oclee-Brown says has finally made it out of R&D after “six or seven years.” It works alongside the digital distortion correction and is built into the woofer to physically monitor its movement. This can then better inform the electronics with what is really going on in the cabinet, and help to further minimize distortion and compression.

Big Bar Problems

This is a large soundbar, stretching around 47 inches long and 10 inches deep, but only stands about 4 inches tall. That gives it a nice low profile for sliding underneath a TV, or for wall mounting, but still makes it a big bar to accommodate—it struggles to fit on either of my TV stands without poking off the ends slightly.

It’s designed to be paired with TVs of at least 55 inches, Oclee-Brown suggests, so no surprise then that it doesn’t look out of place beneath the 75-inch Samsung TV I am testing it with.

The KEF Xio is available in a choice of slate black and silver gray (pictured here).

Courtesy of KEF

It's perhaps not as striking to look at as something like the Sonos Arc Ultra (9/10, WIRED Recommends), though its wall-mounted position is a bit more interesting. Oclee-Brown notes the design has been created around what's been necessary to maximize the performance without compromise, which is king here.

That said, there’s no separate subwoofer included, nor satellite surrounds, as you’ll find in something like the 11.1.4-channel Samsung Q990D (8/10, WIRED Recommends). The focus is on simplicity. Adding a separate subwoofer connection is possible right now (of course KEF recommends something like its KC62 or above, but you can add whatever you wish), but adding wireless surrounds is something KEF hopes to offer around September time, according to Oclee-Brown. This will require another outlay—the KW2 RX adapter ($160)—though it's hoped this will be built into future products.

That's all going to add considerable additional cost onto an already hefty price, but at least the option is, or will be, there.

Of course its standalone 5.1.2-channel setup is going to be most appealing for someone who is considering a soundbar setup to minimize the number of black boxes in their home. And while it can be easy to compare it on paper with something like the Samsung bar, or even the 9.1.4 Sonos Arc Ultra and think it looks to offer less performance, you’ll only need to listen to it to find that is clearly not the case.

As well as Atmos, the KEF Xio offers support for DTS:X and Sony 360 Reality Audio, and has an eARC HDMI port for connecting your TV (yes, only one—you'll need to do your switching on the TV, somewhat unusual at this price), an optical input for other kit (please don’t buy this soundbar and use optical to connect it to your TV—it’s an aging connection that won’t make the most of the Xio’s performance), a sub out and a Bluetooth pairing button.

However, during setup via the KEF Connect app—which was incredibly straightforward via AirPlay on iOS—you will also be able to load this bar onto your home wi-fi network (ethernet is also available if you prefer). This will then allow you to use your choice of Spotify, Tidal and Qobuz Connect, GoogleCast or Apple AirPlay 2 to play better quality music via wi-fi on the soundbar.

The app is also where you’ll access things like the Xio’s room fuss-free calibration feature, choose a sound profile (Default, Music, Movie, Night, Dialogue and Direct—I preferred Default most of the time, but Music works well for stereo music), set timers and select your source. There is an included remote (and a handful of buttons on the soundbar itself if you need them) but you won’t find lots of use for it if you have the KEF Connect app close to hand.

No Delay to Play

From plugging it in and connecting it to my TV, it is up, running and calibrated within minutes. And from the get go, there’s no doubting the pedigree that this soundbar is working with.

There are a handful of controls on the soundbar itself.

Photograph: Verity Burns

The scale here is huge. It’s almost certainly the first thing you’ll notice, even at more reasonable volumes. It effortlessly fills my living room with rich, detailed sound—and this is just from daytime TV. It’s such a big sound that it almost encourages you to reach for the volume button to see just how far it can go. Spoiler alert: it’s more than you will likely ever need, but if you want it, the incredibly low levels of distortion mean it’s pretty much usable volume, all the way to the top.

Godzilla Minus One in Dolby Atmos has plenty for the Xio to get its teeth into, and it takes up every opportunity to show it. In the “atomic breath” scene, where Godzilla lets rip on the Tokyo district of Ginza, the Xio digs admirably deep for the hefty rumble behind every stomp. As buildings are turned to rubble with each devastating tail swish, the impact is punctuated by a satisfying thud, followed by the finer detail of the falling debris that isn’t lost in the chaos. Alongside the power, here’s nuance here too.

When the atomic fire ball is unleashed and what remains of the district is completely destroyed, you get an even greater sense of width and sound placement, with plenty of height from the Atmos channels coming into play as glass shatters around you and rubble rushes in all directions across the screen. It’s incredibly agile in its sound placement, and one that is well projected into the room—escaping the confines of the bar almost entirely.

Adding a separate sub would arguably dig deeper still for some of the deepest bass effects, but it’s hard to imagine this feeling like it’s lacking for the people it is aimed at. It has to be one of the best all-in-one demonstrations of bass performances I’ve heard—clearly more powerful than something like the Sonos Arc Ultra.

Switching it up to Spider-Man: Into the Spiderverse and, aside from the show-stopping explosion handling, another notable feature here is how dialogue is immediately more direct, detailed and engaging. You are instantly reminded of how much is left behind by TV speakers, or smaller soundbars like the Sonos Beam. Even simpler scenes feel all the more interesting due to improved detail retrieval, with a fuller bodied sound that is far more dynamic. This remains true even at lower volumes, which are notoriously more difficult to inject with the same life.

This character pulls through into music too, a perhaps unsurprising strong point of the KEF Xio, which has clearly been tuned with music in mind.

The KEF Xio's connectivity covers the main bases, including HDMI eARC, optical, and a subwoofer out.

Photograph: Verity Burns

“You can get away with a lot in terms of movie sound because you don't have as much of a point of comparison for a chase scene or something like that,” says Oclee-Brown. “And in all the movies we watch, none of that's recorded audio—it's all synthesized. But playing a piece of live jazz? I know what this should be like. So when we developed this, the first thing we did was put music on it in the listening room.”

The KEF Xio handles music as confidently as it does soundtracks, and with a level of refinement that you might not expect from a soundbar. Of course, if music is your main focus then spending a similar amount of money on the KEF LS50 Wireless II would offer a better stereo performance, both in terms of separation, expression and subtlety—but then you wouldn’t have Atmos, nor the more convenient form factor that probably had you considering a soundbar in the first place.

"Why should [separate speakers] have to be the ideal?,” adds Oclee-Brown. "We’re firmly of the belief that the future for hi-fi is to make smarter, more integrated products. That started with the LS50, and the Xio is just a continuation of that. I think what is best is going to come down to what suits somebody's space and their emphasis.”

There is, of course, no getting away from that eye-watering price tag, and the size of market that makes this product of interest to. People had just about got their head around spending the best part of $1,000 on a soundbar, so to more than double that is a big ask.

It requires that sweet spot of someone who cares enough about their TV and living room audio to spend $2,500 when they could spend much less on something that still does a pretty good job. But it also needs someone who also still needs that convenience first, over the out-and-out performance of a surround sound system. In many ways, it’s a hard sell in a small market, and that is perhaps one of the reasons why KEF is only selling directly for now. But if you are looking for the best all-in-one soundbar sound, and have the budget to pay for it, then this is undoubtedly it.