Sonos Arc Ultra Review: Powerful Bass, Impressive Atmos

Sonos’s new flagship soundbar, the Arc Ultra (priced at £1000), aims to deliver an even richer audio experience than the original Arc. Incorporating a compact, built-in woofer dubbed “Sound Motion,” it promises deep bass without necessarily requiring an external subwoofer. Here’s our in-depth review following several days of testing.

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At first glance, you’d be hard-pressed to distinguish the Arc Ultra from its predecessor. The sleek, elongated shape remains, with the same perforated aluminium finish in either black or white. Look closely, and you’ll see a subtle protrusion around the back housing the touch-sensitive controls (microphone, playback, skip, and volume).Dimensions come in at roughly 117.8 × 7.5 × 11.06 cm, weighing around 5.9 kg. Notably, it’s about a centimetre slimmer than the first Arc, making it that little bit more discreet under your TV. Around the back, you’ll find a recessed compartment with buttons and a deliberately sparse set of coections:

• Ethernet port
• Power input
• Single HDMI port

The limited connectivity means you rely on your TV’s eARC or ARC HDMI output for full Dolby Atmos support. If your TV lacks an ARC port, you can use an optical adapter, though you’ll be limited to stereo and standard 5.1 audio. There’s no included remote, but you can easily set your TV’s remote to control the bar’s volume within the Sonos app.

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Sonos’s revamped mobile app—while initially rocky at its launch—has matured considerably. Setup takes about ten minutes and guides you through everything from linking to your Wi-Fi network and streaming services to calibrating the bar for your room. The bar supports Dolby Atmos (Dolby Digital Plus via ARC, Dolby TrueHD via eARC), and you can add the new Sonos Sub 4 or rear satellites if you wish.Within the app, you can manage audio modes, EQ adjustments, loudness, and “night mode” or “speech enhancement”—all well-implemented. Trueplay calibration is a hallmark of Sonos, shaping the Arc Ultra’s output to your space. Ideally, use an iPhone to walk around your room for detailed measurements. Alternatively, the bar’s own mics can perform a simpler version of Trueplay if you don’t have an iOS device.Also worth noting is that AirPlay 2 is on board, but Google Cast remains absent. Alexa and Sonos Voice Control are the supported voice assistants, with limited local functionality for each. For Google Assistant or Siri, you’ll need another device to link them.

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Sonos has packed the Arc Ultra with 14 drivers and 15 Class D amplifiers, including seven silk-dome tweeters (two upward-firing), six midwoofers, and the highlight—a novel built-in woofer dubbed Sound Motio. This technology stems from Sonos’s 2022 acquisition of Dutch startup Mayht, known for its iovative approach to subwoofer transducers.Sound Motion consists of a double membrane powered by four motors, delivering a more precise and dynamic bass performance. Effectively, it’s like having a mini sub integrated into the soundbar. Sonos claims it doubles the bass response over the original Arc without increasing size—and from our testing, that claim largely holds true. Explosions, rumbles, and bass-heavy tracks all gain more depth and impact than you’d expect from a standalone bar.

Minor Midrange Dip

While the top and low ends are impressive, mids can sound slightly recessed in music playback, leaving vocals less forward. Yet for most TV, film, and mainstream streaming audio content, the overall signature is balanced enough—and can be fine-tuned via the app’s EQ, loudness settings, or voice enhancement features.

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As a 9.1.4-chael system (thanks to side-firing and up-firing drivers, plus that dedicated woofer), the Arc Ultra presents a broad Dolby Atmos soundstage. True, it doesn’t replicate overhead channels as convincingly as a fully equipped surround system with discrete ceiling speakers, but the sense of height and spatial envelopment is still strong. Action scenes, for instance, feel vividly expansive, with crisp directional effects.If you want even more bass, the new Sonos Sub 4 can be added. With two elliptical 5×8-inch drivers in a push-push arrangement, it further boosts low-end extension—especially suitable if you have a larger living room. However, the Arc Ultra’s own bass presence may already suffice for many smaller or mid-sized spaces, making the additional sub more of a luxury than a necessity.

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The standout feature of the Arc Ultra (at ~£1000) is undoubtedly Sound Motio, an integrated woofer inherited from Mayht’s breakthrough technology. This solution substantially amplifies bass output compared to the original Arc, negating the immediate need for a separate subwoofer—unless your room is particularly large.Whether you’re listening to music (with only a minor critique on midrange detail) or watching a film in Dolby Atmos, the Arc Ultra delivers an engaging and dynamic soundstage—even without rear satellites. Meanwhile, the Sonos app—once criticised—is now stable, intuitive, and ties into a robust multi-room ecosystem. For those willing to invest, the Arc Ultra stands among the top-tier offerings in the premium soundbar market.