KEF XIO review: a soundbar that’s as musical as it is immersive

The first soundbar from the British manufacturer, the KEF XIO features a sophisticated audio architecture, designed to offer both spectacular home theater immersion and true musicality for audio listening sessions. Uni-Q MX technology, powerful bass without a subwoofer, Dolby Atmos 5.1.2 channel compatibility, 820 watts of power and high-resolution streaming services: everything seems to be present to appeal to music lovers and film buffs alike. Can this latest-generation soundbar compete with the best Dolby Atmos soundbars around? Find out in our review.

Presentation

Design

An essential reference in the world of hi-fi and home theater speakers, KEF has also made its mark on the connected speaker market in recent years with its iconic LSX and LS50 Wireless series, acclaimed for their modern design and acoustic performance. For its first soundbar, the brand is playing the premium card with a model priced at €2,299, capable of challenging industry tenors such as the Devialet Dione, the Sennheiser Ambeo Soundbar Max or the Sonos Arc Ultra. All claim to deliver an immersive experience and deep bass, without the need for a separate subwoofer. But the KEF XIO intends to set itself apart by adopting a more audiophile approach, relying on in-house technologies derived from the brand’s high-fidelity speakers. A recipe that appears to be working, as this freshly launched model has been awarded the prestigious 5-star label by What Hi-Fi?

The premium aspect of this soundbar is confirmed as soon as you unpack it. The KEF XIO looks serious, both in terms of its build quality and its size. At 121cm long and 16.5cm deep, it is more massive than most of today’s soundbars, at a time when compactness often takes precedence over performance. Its format is similar that of a Devialet Dione, but the KEF model stands out for its more restrained height of just 7cm, making it easier to slide in front of most current TVs without hiding the bottom of the picture.

For those who prefer wall-mounting, the XIO comes with a dedicated mounting kit. Once again, KEF pays attention to the details: an integrated gyroscopic sensor automatically detects the orientation of the bar (laid flat or wall-mounted) and reconfigures the driver assignment accordingly. This function guarantees optimum spatial reproduction in all situations, preserving the coherence of vertical and lateral effects.

KEF’s heritage is embodied in a minimalist, elegant design that blends easily into any interior. Part of the top panel is covered by a brushed aluminum plate, reinforcing the unit’s luxurious appearance. The rest of the chassis is clad in an elegant acoustic fabric that envelops all visible surfaces, including the upper extremities. It elegantly conceals the 12 drivers distributed throughout the soundbar. Two finishes are available: gray and black, neutral, matte tones that discreetly fade into the background.

Ergonomics and functions

Ergonomics have also been simplified to the max, with a touch-sensitive control panel located on the bar to manage essential functions, including source selection, power-on and volume. The sensitivity of these buttons can be adjusted with 10 different levels. These various controls can also be accessed via the included infrared remote control, which also features two customizable buttons for quick access to favorite functions. But it’s through the KEF Connect app that soundbar reveals its full potential. Shared by all the brand’s connected speakers, it centralizes all settings, from equalization to source selection, acoustic calibration and access to various streaming services. The main platforms are supported, with direct access to Qobuz, Tidal, Amazon Music, Deezer and Spotify. Each service is well integrated, ensuring fluid, intuitive navigation through albums, playlists and suggestions specific to each platform. The interface is modern and well thought-out, and allows you to customize the home page for quick access to the features you need most.

The KEF Connect app also lets you enjoy web radios, podcasts and music shared over the local network in DLNA. The integrated DAC supports the majority of audio formats, including FLAC, WAV, AIFF, ALAC, AAC, WMA, MP3, M4A, LPCM and Ogg. It can play these at up to a resolution of 24-bit/384kHz. In addition, AirPlay 2, Bluetooth 5.3 and Chromecast compatibility make it easy to connect to a smartphone, computer or tablet. All of these streaming features enable the KEF XIO to be used as a true connected speaker.

Dolby Atmos and DTS:X 5.1.2 channels

Beneath its elegant silhouette, the KEF XIO soundbar conceals a genuine technological armada. Dolby Atmos and DTS:X compatible across 5.1.2 channels, it houses twelve drivers, powered by as many class D amplifiers for a total instantaneous power of 820 watts. This system takes full advantage of the acoustic innovations developed by the manufacturer for its hi-fi speakers. These include six Uni-Q MX drivers, a miniaturized version of the famous Uni-Q coaxial technology developed by KEF over several decades. The midrange cone is mechanically separated from the tweeter, so that each element can operate independently and reproduce a specific frequency range. A single common voice coil powers this assembly in order to take up less space while guaranteeing perfect temporal coherence between frequency ranges. The result is excellent dialogue clarity, thanks to the rich midrange and transparency of Uni-Q technology. Two full-range drivers round out this configuration to widen the soundstage.

The other tour de force of the KEF XIO soundbar is its ability to deliver deep, powerful bass, without the need for a separate subwoofer. To achieve this, KEF has integrated four P185 bass drivers, specially designed for this model. Their 7″ x 2″ format maximizes the emission surface to deliver acoustic pressure equivalent to a driver with a diameter of 4 inches. They are mounted back-to-back in a force-cancellation configuration to deliver deep, powerful bass without unwanted vibration or mechanical distortion.

Each P185 driver benefits from P-Flex technology, inspired by the KEF KC62 subwoofer. This concentric fold surround acts as a mechanical counterweight, resisting the internal pressure of the cabinet and ensuring more linear cone movement. To complete the package, KEF has integrated a VECO (Velocity Control) sensor, to monitor cone movement in real time and correct the slightest deviation. Even without an additional subwoofer, the KEF XIO delivers dense, deep bass down to 34Hz. Bass-heads will still be able to add an external subwoofer, either wired via the dedicated output or a wireless model using the KEF KW2 RX module specifically designed for the brand’s subwoofers.

Calibration and settings

To adapt to any environment, the KEF XIO soundbar is equipped with an acoustic calibration system with an integrated microphone. This enables it to automatically adapt the spatialization of sound effects according to the properties of the room. The process takes less than a minute, and only requires the user to indicate the height at which the bar is installed. In addition, you can fine-tune the settings by adjusting the treble and bass levels (+/- 10 dB). For nighttime movie sessions, a night mode limits dynamics so as not to disturb those around you, while a dialogue mode enhances the clarity of voices.

Connectors

To connect to the TV, the KEF XIO focuses on the essentials: an HDMI eARC port to retrieve sound from the content you’re watching, whether it comes from a Blu-ray player, TV box or directly from streaming services (Netflix, Prime Video, Disney+, etc.). This port ensures uncompressed audio transmission, including for multichannel formats such as Dolby Atmos or DTS:X, while simplifying control via the TV’s remote control. For older screens, an optical input is also available. Whatever the source used, the KEF XIO benefits from the algorithmic Music Integrity Engine (MIE) processor inherited from the brand’s connected speakers and subwoofers. Here, adapted to the world of cinema, it deploys numerous DSPs, including a spatial virtualization system that expands the soundstage. Even from stereo or 5.1 content, the bar is capable of generating an immersive three-dimensional sound, with convincing ambient effects. Last but not least, the soundbar also features a subwoofer output. Crossover frequency and gain are adjustable via the KEF mobile app.

Key features

• 5.1.2-channel soundbar
• Acoustic calibration with built-in microphone
• 12 drivers
• Total power: 820W
• Streaming services
• Dolby Atmos and DTS: X
• Dimensions (WxHxD): 1210 x 70 x 165mm

Listening conditions

For this test, we connected the KEF XIO via HDMI eARC to several recent Dolby Atmos-compatible TVs. Getting started was quick and easy, thanks to the KEF Connect app, available on iOS and Android. Once the device is switched on, simply select the XIO in the app, which automatically detects it and initiates the connection to the WiFi network used by the smartphone. A few moments later, the bar is ready for use. The next step is to launch acoustic calibration, which enables the bar to automatically adjust its sound reproduction according to its position in the room. The app then lets you associate the streaming services of your choice, activate different listening modes (music, film, stereo, night, etc.) and adjust bass and treble levels.

Listening impressions

Home theater

The KEF XIO soundbar demonstrated a true sense of showmanship and impressed us with its ability to generate powerful, punchy bass without the need for a separate subwoofer. The four P185 drivers delivered deep, impactful and perfectly controlled lows. Even in a living room of over 60m², they offered real physical impact that shook the sofa and brought action scenes to life with great realism. The roar of an engine in Mad Max: Fury Road, the acoustic pressure of rockets in Interstellar or even the battles in Gladiator II, were rendered with palpable energy, without overpowering the other sound effects.

These different effects were effectively spatialized through an extended, enveloping soundstage. Ambiences extended far beyond the physical limits of the bar, with the impression that the sound was emanating from the walls, or even from the back of the room. This feeling of space was reinforced in rooms of under 25/30m². The front soundstage was then particularly vast, with perfectly centered dialogues that were always clear and distinct, even in the densest passages. Surround effects were highly credible. In many scenes, they created a feeling of depth, as if invisible rear speakers were taking over.

Dolby Atmos tracks were just as convincing. Vertical effects were often perceptible at the center of the room and above the listener. While this height effect varied depending on the scene and mix, the KEF XIO demonstrated a remarkable ability to create a coherent, enveloping sound bubble.

Music

When listening to music, the KEF XIO broke free from its format thanks to its excellent spatialization abilities, which allowed it to reconstruct a wide, well-structured soundstage, as if two speakers were positioned on opposite sides of the room. The placement of instruments was clear, stereo effects were pronounced, and the soundstage stretched out naturally, providing a feeling of space and texture rarely achieved with a soundbar.

Vocals were pure and well articulated, with remarkable presence. The midrange, deliberately emphasized, added warmth and texture to vocal timbres and instruments alike. The highs, on the other hand, were a little more discreet, but remained sufficiently defined to ensure good legibility without ever sounding harsh. This choice of tonal balance gives the XIO a smooth, fluid sound, particularly pleasant over long listening sessions, and well suited to pop, rock, electro or film music.

The quadruple P185 drivers, already convincing for home theater, offered a solid and nuanced foundation, giving depth and body to the tracks. On intimate jazz compositions, the soundbar sometimes seemed a little less expressive, struggling at times to convey the finesse of micro-details or the subtlety of silent passages. However, the sound remained balanced, wide and very pleasant. As a result, this soundbar could easily replace a small pair of connected speakers.

KEF XIO vs Devialet Dione

When compared to the Devialet Dione, the KEF XIO takes a more audiophile, balanced approach. Where the Dione impresses with its raw power, oversized bass and spectacular, sometimes demonstrative sound, the XIO focuses on finesse, precision and tonal coherence. Its soundstage is more open and airy, with clearer voices and mids, particularly with music.

Is the soundbar KEF XIO for you?

If you’re looking for a high-end soundbar capable of replacing a multichannel home theater system and a pair of connected speakers, the KEF XIO deserves your full attention. It’s aimed above all at those who want to enjoy top-quality sound without multiplying components, or cluttering up their living room with cables and speakers. Thanks to its great versatility, it will excel both in bringing action films to life with great realism, and in listening to music, with its natural, full and coherent reproduction. Thanks to its quadruple woofers, it will also appeal to fans of deep, powerful bass.