KEF XIO soundbar first review: Sensational debut offers style, substance, and sonic science

British audio specialist KEF may have spent over six decades refining the art of home audio, from classic Hi-Fi to some of the most revered wireless speakers in the business, but it’s only now that the brand has trained its considerable acoustic firepower on the humble soundbar. 

The result is the XIO, the company’s first all-in-one home theatre sound system. I had an early listen at the KEF Music Gallery in London, and came away convinced that the XIO isn’t so much dipping a toe in the water, as it is diving in headfirst.

The KEF XIO is unapologetically high-end in terms of design and performance. Proffered as a 5.1.2-channel home cinema solution, with dedicated height drivers for Dolby Atmos, DTS:X, and Sony 360 Reality Audio, the bar promises serious sonic immersion from an easy-to-accommodate single unit.

Under the hood is a full suite of KEF’s proprietary tech: Uni-Q MX drivers, a custom P185 low-frequency unit with P-Flex surround, Velocity Control Technology (VECO), and the brand’s Music Integrity Engine (MIE) DSP.

These buzzwords position the XIO as a serious challenger to the Sennheiser Ambeo Soundbar Max and Bang & Olufsen Beosound Stage, both premium models that I have reviewed and like very much.

The KEF XIO isn’t your average slimline TV add-on. It’s unapologetically high-end in terms of design and performance…

Understated style, considered design

Build quality, as you’d expect from KEF, is top tier.  Wrapped in fabric, with just the right amount of industrial chic, the XIO can be used either flat or wall-mounted. For my demo, it rested on a credenza, said to be the best option sonically.

It may be slim, but it is wide, so plan to partner it with a large screen – 65-inches upwards. It’s available in Slate Black or Silver Grey.  

There’s an intuitive interface on the top panel, and it ships with a smart-looking remote control. There’s also the option to interact through the KEF Connect app. Both offer straightforward access to presets, Night, Music, and Dialogue Modes, and more advanced EQ settings for the acoustically curious.

Connectivity includes HDMI eARC, digital optical audio, and subwoofer output, along with Wi-Fi, Ethernet, AirPlay 2, and Google Cast. There’s no HDMI pass though option, which is a little disappointing.

Streaming services are covered via KEF’s W2 Wireless Platform, borrowed from its acclaimed LS wireless speakers, which supports everything from Tidal to Qobuz, Amazon Music and Deezer.

Perhaps more impressive is what’s under the bonnet. The Uni-Q MX drivers are a compact version of KEF’s famed coaxial arrays, placing tweeter and midrange on the same axis for pin-point imaging. These are paired with 12 class D amps, giving a total power output of 820W, driving that 5.1.2-channel layout. Intelligent Placement Technology (IPT) calibrates the sound to the room, factoring in furniture and positioning to adapt the output accordingly.

Then there’s VECO – Velocity Control Technology – a feedback loop that constantly monitors cone movement to reduce distortion and keep bass clean. The low-end is further supported by KEF’s P-Flex surround, allowing greater control of pressure inside the cabinet, borrowed from its award-winning KC62 and KC92 subwoofers. That’s a lot of leading edge tech.

Precision, power and poise

At the KEF Music Gallery, I enjoyed a private preview of the XIO in action. Ready Player One’s kinetic, cameo-packed race sequence proved a perfect stress test. The soundbar’s spatial performance is reassuringly expansive, with movement tracked across the front soundstage and into the vertical plane with uncanny precision. Dialogue was clean and centered, never lost to background chaos, and sound effects arrived with both scale and nuance.

There were moments, especially during dynamic transient shifts, when the bar comes remarkably close to mimicking the wraparound feel of a discrete surround system, despite lacking rear speakers.

Bass, as advertised, runs deep. The onboard P185 LF drivers punch with real authority – enough, in fact, to render a separate subwoofer unnecessary for most rooms. That said, I did try the XIO with a wireless KEF subwoofer, and while the experience was certainly heavier, it verged on overkill, particularly with music. For most users, the XIO on its own hits the sweet spot: rich, resonant, and controlled.

Music playback is generally impressive, though there’s a slight emphasis on bass that gives some tracks more weight than is probably intended. Vocals sit naturally in the mix, with the Uni-Q MX drivers doing fine work in separating instruments and projecting detail. It’s not a neutral studio monitor sound, but it’s engaging and full-bodied. 

Final thoughts and verdict

With the XIO, KEF has delivered a soundbar that gets all the high performance fundamentals right at its first attempt. It looks refined, sounds remarkable, and offers a degree of sonic integrity cheaper soundbars can only aspire to. 

For those who want cinematic sound without multiple boxes or cluttered wiring, it makes a compelling case, and an audition is highly recommended.

The XIO may be KEF’s first soundbar – but it certainly won’t be its last.

The KEF XIO Soundbar sells for £1,999, and is available July 17 2025. Optional wireless subwoofer accessories launching September 2025.