How We Research
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want studio-grade sound and marathon battery life, choose KEF Mu7; if you need spatial audio and a tighter tie-in with a home theater setup, choose Sonos Ace Noise Cancelling.
• KEF Mu7 — biggest strength: Up to 40 hours of playback with Bluetooth and ANC running, plus a 15-minute fast charge that yields 8 hours. That's the kind of endurance that makes charging anxiety disappear on long trips.
• KEF Mu7 — biggest trade-off: It leans on Bluetooth 5.1 and touch controls, and it's a heavier-feeling design at roughly 1 kg with a hard leather-style case. That's a lot of headphone to pack.
• Sonos Ace — biggest strength: Dolby Atmos with dynamic head tracking, lossless audio over Bluetooth or USB-C, and TV Audio Swap with compatible Sonos soundbars. It's built for immersive home audio.
• Sonos Ace — biggest trade-off: Up to 30 hours with ANC on, which is solid but a clear step below the Mu7, and its headline features assume you already live in the Sonos ecosystem.
• Pick KEF Mu7 if you want the longest battery life and a wired 3.5 mm fallback for pure listening.
• Pick Sonos Ace if you want spatial audio, USB-C audio, and seamless handoff to a Sonos soundbar at home.
The Mu7 is the headphone for someone who cares about the fundamentals: battery, sound delivery, and simple control. KEF pairs a 40 mm dynamic driver with a 20 Hz–20,000 Hz frequency range and 64 ohm impedance, and pushes high-resolution audio over aptX HD via Bluetooth 5.1. The design comes out of a collaboration with Ross Lovegrove, and the minimalist, round-earcup framing is clearly aimed at people who want their gear to look considered rather than tactical.
Battery is where the Mu7 separates itself. Up to 40 hours with Bluetooth and ANC both engaged is genuinely all-week territory for a commuter, and the 15-minute fast charge delivering 8 hours is the spec I'd lean on most — plug in during a coffee, walk out with a full workday of playback. Smart Active Noise Cancellation tracks environmental sound rather than applying one fixed level of cancellation, which suits a mix of office, train, and street noise.
Who should skip it? If you want your headphones to interact with a TV or a multi-room speaker system, the Mu7 has no equivalent feature — its connectivity story is Bluetooth, plus a 3.5 mm jack and USB-C charging in the box. And if you prefer physical buttons over touch controls, this isn't your pick; the Mu7 is touch all the way. It's also worth checking the current price on Amazon before deciding, since the feature set is aimed at the higher end of the category.
The Ace is the headphone for the person whose listening doesn't stop at music. Sonos builds it around Dolby Atmos with dynamic head tracking and an "industry-leading" spatial audio experience — and, importantly, it supports lossless playback over both Bluetooth 5.4 and USB-C. That USB-C audio path is the real differentiator: it's a wired digital connection, not just a charging port, and it comes with a USB-C to USB-C cable plus a USB-C to 3.5 mm cable in the box.
The second differentiator is TV Audio Swap. If you own a compatible Sonos soundbar — Arc Ultra, Arc, Arc SL, Beam (Gen 2), Beam (Gen 1), or Ray — you can move TV audio back and forth between the soundbar and the headphones. That's a genuinely useful feature for late-night viewing when you don't want to wake the house. It doesn't group like other Sonos speakers, and you don't need the app just to pair over Bluetooth, but some features do require the app on an internet-connected device.
Comfort is clearly a design priority: plush memory foam, soft vegan leather, and a fit that Sonos says suits all head shapes and hairstyles. ANC is described as world-class, and battery runs up to 30 hours with ANC on. Rapid charging is excellent in the other direction too — 3 minutes gets you up to 3 hours. Bluetooth range is a generous 30 meters.
Who should skip it? Anyone who isn't in the Sonos ecosystem loses a chunk of the Ace's value, since TV Audio Swap needs a compatible soundbar. And if maximum battery life is your top line item, 30 hours trails the Mu7.
• Best battery life → KEF Mu7. Up to 40 hours with ANC on versus up to 30 hours on the Ace.
• Best fast-charge ratio → KEF Mu7. 15 minutes for 8 hours beats 3 minutes for 3 hours in absolute terms, though the Ace wins on raw charging speed.
• Best for spatial audio and movies → Sonos Ace. Dolby Atmos with dynamic head tracking has no counterpart on the Mu7.
• Best for a Sonos home theater → Sonos Ace. TV Audio Swap works with Arc Ultra, Arc, Arc SL, Beam Gen 1/Gen 2, and Ray.
• Best for wired listening → Sonos Ace. USB-C digital audio is a step beyond the Mu7's 3.5 mm analog jack.
• Best Bluetooth version and range → Sonos Ace. Bluetooth 5.4 with a 30 m range versus Bluetooth 5.1 with 10 m.
• Best for high-resolution Bluetooth codecs → KEF Mu7. aptX HD support is explicit here.
• Best for all-day comfort design → Sonos Ace. Memory foam and vegan leather with a fit built for varied head shapes.
• Best for pure simplicity → KEF Mu7. Bluetooth, 3.5 mm, touch controls, done.
In my opinion, I'd buy the KEF Mu7 if my listening is mostly music and travel. The 40-hour battery with ANC on, the 8-hours-from-15-minutes fast charge, and aptX HD over Bluetooth are the specs that matter most day to day, and the 3.5 mm jack is a useful safety net. I'd only go Sonos Ace if I already owned a compatible Sonos soundbar or genuinely wanted Dolby Atmos spatial audio. If neither of those applies, the Mu7's endurance is the more valuable everyday advantage.
The KEF Mu7 is better on paper: up to 40 hours with Bluetooth and ANC enabled, against up to 30 hours for the Sonos Ace with ANC on. The Ace charges faster in raw minutes, but the Mu7 lasts longer per charge.
Does the Sonos Ace work without a Sonos soundbar?
Both use active noise cancellation and both are described as strong by their makers — the Mu7 with Smart ANC that adapts to environmental sound, the Ace with world-class ANC. The data sheets don't give a measurable cancellation figure, so the honest answer is that they're aimed at the same premium tier.
The Sonos Ace, clearly. Dolby Atmos with dynamic head tracking and TV Audio Swap are built for screen content. The KEF Mu7 is a music-first headphone with a 3.5 mm wired option, not a home-theater companion.
Not for basic Bluetooth pairing. The app is needed to enable select features and to register the headphones, and it works even when your phone isn't on your home WiFi.
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