KEF XIO Soundbar Review: Audiophile-Grade Audio Meets Gamer Frustration

The sleek silhouette of KEF’s first-ever soundbar promises sonic nirvana for cinephiles, yet its single HDMI port sparks a dilemma for next-gen console warriors. As Dolby Atmos systems become entertainment centerpieces, the premium £1,999/$2,500 KEF XIO soundbar delivers breathtaking audio fidelity trapped by a critical connectivity gap.

KEF XIO Soundbar: Design and Engineering Mastery

KEF defied expectations by opting for subtle sophistication over flamboyance with the XIO. Unlike the brand’s signature visible Uni-Q drivers in models like the LS series, this soundbar embraces a stealthy, ultra-thin profile perfect for flush wall-mounting beneath OLED TVs. Measuring just 3.9 inches tall, its matte-black aluminum chassis disappears into modern setups while radiating premium craftsmanship.

Setup is refreshingly intuitive—a rarity in high-end audio. The KEF Connect app seamlessly guides users through calibration, offering granular EQ adjustments and streaming service integration. Bluetooth 5.3 ensures stable wireless playback, while WiSA compatibility allows future expansion to wireless surround speakers. Though minimalist in ports (optical, Ethernet, and one HDMI eARC), its physical elegance matches KEF’s legacy of acoustic innovation.

Revolutionary Sound Performance

Don’t let the slim form fool you—KEF’s proprietary drivers defy physics. Through advanced motor systems and computational audio, the XIO moves 40% more air than conventional slim soundbars. The result? Bass that punches deep into the 35Hz range without a subwoofer, while maintaining crystalline dialogue clarity. During testing, the opening tsunami sequence in Dune: Part Two showcased terrifying low-end rumble without muddiness, while Hans Zimmer’s score layered textures with holographic precision.

Dolby Atmos immersion is where the XIO truly shines. Height channels project rainfall or helicopters convincingly overhead, and the soundstage extends far beyond the bar’s physical limits. In quieter moments, like dialogue in The Crown, voices anchor centrally with natural tonality. Independent lab measurements confirm <0.5% THD at 90dB—exceptional linearity for a single-unit system. As KEF’s Global Product Manager, Rafael Todeschini, notes: “We reimagined driver efficiency to achieve full-range sound from an unprecedented footprint.”

The HDMI Limitation: A Gamer’s Dealbreaker

Here’s where the dream stalls. The XIO’s solitary HDMI eARC port forces all sources through your TV first. For casual viewers, this simplifies connections. But for PlayStation 5 or Xbox Series X owners, it’s catastrophic. Most 2020–2024 TVs—including Sony’s A95L and popular TCL/Hisense models—include just two HDMI 2.1 ports. One is typically reserved for eARC, leaving only one input for 4K/120Hz gaming.

Connecting the XIO consumes that eARC port, meaning:

• Dual-console households must choose which system gets full 120Hz VRR
• The second console downgrades to 60Hz, sacrificing fluidity
• Users face constant cable-swapping or $150+ HDMI switchers

This omission feels inexplicable at this price. Competing bars like Samsung’s HW-Q990D offer three HDMI 2.1 inputs with 4K/120Hz passthrough, effectively adding ports rather than consuming them. Even Sonos’ Arc Ultra faced backlash for similar limitations. As noted by HDMI.org’s official specifications, 2.1 bandwidth is essential for uncompressed gaming features like ALLM and QMS.

Competitive Landscape and Alternatives

Positioned against premium rivals, the XIO’s acoustic performance dominates but its practicality falters:

Soundbar	HDMI 2.1 Inputs	4K/120Hz Passthrough	Price
KEF XIO	0	❌	$2,500
Samsung HW-Q990D	3	✅	$1,900
Sonos Arc Ultra	0	❌	$1,599
Sennheiser Ambeo Max	2	✅	$2,499

For audiophiles prioritizing sound purity, the XIO is peerless. But gamers needing future-proof connectivity should consider the Sennheiser Ambeo Max or Samsung Q990D. KEF’s response to What Hi-Fi? confirms they’re “evaluating input options for future models,” suggesting a hardware revision could resolve this.

The KEF XIO soundbar redefines slim-profile audio excellence with thunderous bass and ethereal Atmos height effects—yet its single HDMI port sabotages next-gen gaming potential. Unless KEF addresses this oversight, multi-console owners should explore alternatives or await version 2.0. Test your TV’s HDMI capacity before investing, and explore soundbars with passthrough to preserve gaming performance.

Must Know

Q: Does the KEF XIO support Dolby Atmos and DTS:X?
A: Yes, the XIO decodes both Dolby Atmos and DTS:X formats via its eARC HDMI port. It also handles LPCM 7.1 for uncompressed gaming audio. However, immersive formats require streaming services or physical media, as standard broadcast TV won’t trigger them.

Q: Can I add wireless rear speakers to the KEF XIO?
A: Absolutely. Through KEF’s WiSA certification, you can integrate the company’s LSX II LT or KC62 subwoofer for a 5.1.4 setup. The KEF Connect app manages pairing—no AV receiver needed.

Q: Why do gamers care about HDMI 2.1 passthrough?
A: HDMI 2.1 enables 4K/120Hz gameplay, Variable Refresh Rate (VRR), and Auto Low Latency Mode (ALLM). Without passthrough, consoles connected directly to TVs with limited ports may be capped at 60Hz, increasing input lag during fast-paced titles.

Q: Does the XIO work with older TVs lacking eARC?
A: Yes, via its optical input. However, you’ll lose Dolby Atmos and high-resolution audio formats. Optical connections max out at 5.1 Dolby Digital.

Q: Are there workarounds for the single HDMI port?
A: You could use an HDMI 2.1 splitter or your TV’s built-in apps for streaming. However, splitter reliability varies, and TV apps rarely match dedicated streaming devices for bitrate or audio formats.

Q: How does the XIO’s bass perform without a subwoofer?
A: Surprisingly potent. KEF’s Force-Canceling Drivers eliminate distortion while reaching down to 35Hz—deeper than many soundbar/subwoofer combos. For reference, most human speech sits around 85–255Hz.