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January 3, 2025
Sonos Arc Ultra and Sub 4 Review: Duo Delivers Dynamic Audio Experiences
The $999 Arc Ultra and $799 Gen 4 subwoofer serve as great building blocks for home theater and a zone within a larger Sonos-based whole-house audio system.
Sonos’ new Arc Ultra soundbar and Sub 4 powered subwoofer are the company’s new flagship home theater components. (photo credit: Sonos)
Sonos has been a popular provider of whole-house audio and home theater systems for a long time, and while it has seen some issues in recent years, the subjects of today’s review–the Arc Ultra immersive audio soundbar and Sub 4 powered subwoofer–showcase Sonos still has it when it comes to designing acoustically powerful devices.
These new products build upon the existing Arc and Sub products, and they feature company’s latest audio engineering concepts to underpin a new level of product performance for the high-profile manufacturer.
Like other products within the Sonos product line, the new Arc Ultra soundbar and Sub 4 powered subwoofer can be used as a standalone system together for a really nice home theater—the combination can be used as a zone within a bigger whole-house audio system—and the Sub 4 can also be used to augment smaller Sonos speakers to deliver more impactful bass.
CE Pros and Cons
Pros:
- Setup and installation is easy, and through Sonos’ app the system provides whole-house audio capabilities.
- The Arc Ultra delivers a broad and airy soundstage with good image definition.
- The integration of the Sub 4 is seamless and the sub 4 reinforces the overall dynamics of the combination without calling attention to itself.
Cons:
- My biggest criticisms of the system relate to the app. Navigation isn’t quite as smooth as past versions of the app in my opinion.
- I don’t like how Apple Music is integrated into the platform, but the system’s Apple AirPlay options make up for the shortcomings of the Apple Music integration.
Arc Ultra and Sub 4 Features
The Arc Ultra features a multi-driver array highlighted by an advanced woofer design, along with a half dozen midrange drivers and seven tweeters. These drivers are strategically placed, and the company uses its advanced software and DSP knowledge to reproduce stereo, surround sound, and immersive audio content such as Dolby Atmos.
The new Sub 4 utilizes a unique industrial design and a rarely used driver alignment in which two 5-inch x 8-inch elliptical woofers face one another to create a force-cancelling design. Internally, the subwoofer uses Class D amplification to power those drivers and once again, advanced DSP algorithms to control output of the subwoofer and the Trueplay automatic EQ options.
Other features include Wi-Fi and Ethernet network options, whole-house audio options; the Arc Ultra features HDMI eARC, and the products are supported by Sonos’ proprietary Trueplay automatic equalization technology.
Additional Specs:
- The Arc Ultra incorporates the company’s dual-membrane, four-motor woofer, along with six midrange drivers, and seven tweeters. Sonos says the drivers are powered by a total of 15 internal amplifiers.
- Like other Sonos products, the soundbar is supported by Sonos’ Trueplay automatic equalization (EQ) technologies.
- Sonos states the Arc Ultra supports surround sound formats such as Dolby Digital Plus, Dolby Atmos, Dolby TrueHD, and DTS Digital Surround.
- Users that own a pair of Sonos Ace headphones can utilize the company’s TV Audio Swap option that allows users to play sound through the headphones.
- Internally the Sub 4 incorporates a pair of 5-inch x 8-inch elliptical woofers that face one another in a force-cancelling alignment. Dual Class D amplifiers power the Sonos elliptical drivers.
- EQ options are available through the Sonos App, and Trueplay is also available with the Sub 4.
- The Arc Ultra carries a retail price of $999.
- The Sub 4 powered subwoofer carries a retail price of $799.
Setup
Sonos innovated the setup of modern electronics through the use of an app. Using the app, which I have on my iPhone 15 Pro, I simply followed the prompts the app provides, which walked me through the setup process.
Selecting the app, Sonos software immediately told me that I needed to run an update on the app. Once I completed the update, I plugged the Arc Ultra in and the basic setup took just a few minutes. As part of the setup, I had to place the soundbar on my network and then I added the soundbar to an existing Sonos system.
Other setup items included naming the soundbar and later I would eventually run Sonos’ Trueplay auto equalization technologies. I believe as part of the evolution of the Trueplay platform, Sonos now offers a basic and advanced level. Prior to updating its auto EQ solution, integrators were required to walk around with the phone as part of the EQ measurement process. Through the update that process is now considered the advanced EQ mode. The basic level emits a series of test tones and equalizes the sound through those measurements.
Related: An Unconventional Seating Arrangement Creates Deeply Immersive Home Theater in New Delhi
Running the basic level of Trueplay I would estimate the software took less than a minute to execute the auto equalization of the Arc Ultra soundbar.
Following up the setup of the Arc Ultra soundbar about a week or so later I added the Sub 4 to the mix. To add the sub, it was a similar process that is driven by the app. Selecting the “add” option within the app, the app will then go and discover the subwoofer. Once the Sub 4 was discovered the app uses NFC technologies to add the sub to my Sonos system.
One Interesting item I will point out is that despite seeing the sub and adding the Sub 4 to my Sonos system I could not finish the setup process until I ran a Cat-6 cable to the sub. My conclusion is the Wi-Fi capabilities of the Sub 4 may not be as robust as the company’s other products.
Setup and configuration of Sonos products is driven by the company’s app, which is available to iOS and Android users. (photo credit: Bob Archer CE Pro)
I’ll add that overall, both the Arc Ultra and Sub 4 are easy to setup and easily integrate into an existing Sonos system or into a home as a standalone home theater solution.
Performance
Using the Arc Ultra for streaming media, including Netflix, YouTube and Hulu, as well as broadcast television, and my Apple Music account, which I used through Sonos’ app and via AirPlay, I did find the soundstage to have more air and more spaciousness than the original Arc.
Because of the broad dispersion the new Sonos soundbar there really was no bad seating position where dialog articulation fell off in my living room. Obviously, locations in front of the soundbar were better, but important details such as dialog remain intelligible in less-than-optimal seating locations.
Tonally, I felt the Sonos Arc Ultra was true to the original content, including Fleetwood Mac in stereo, and Chappell Roan and Rush in Dolby Atmos, I thought the Atmos content had a nice level of dynamics particularly with Chappell’s 80s-influenced record, which features a lot of synthesizers electronic drums.
Adding the subwoofer doesn’t produce the dramatic effect that some people may expect. I want to congratulate Sonos’ engineers for resisting the temptation to tune the soundbar and Sub 4 to sound like some of those overrated headphones that pump up the lower frequencies in favor of tonal accuracy and musicality. The integration between the Sub 4 and the Arc Ultra is seamless, and the sub’s low frequency reproduction is smooth down to reasonable levels to add musical bottom-end girth to music and video content.
Final Thoughts on the Arc Ultra and Sub 4
Unsurprisingly, I am impressed with the latest Sonos products. Confirming this impression … yes Sonos has knocked it out of the park with the development and performance of the Arc Ultra and Sub 4. My only criticisms involve the app. Years ago I thought Sonos had the best smart-home app on the market and it wasn’t even close.
Over the years however, other companies have caught up to Sonos with the functionality of their apps and Sonos has fallen back to the pack in some respects. Let me say this first, the app is stable and reliable. It does not crash like many of the inferior apps that exist in the worlds of iOS and Android, but the navigation isn’t quite as user friendly, and the depth of quality isn’t quite where prior versions were.
Getting back to the bottom line, over the years I’ve had the opportunity to try several of Sonos’ soundbars and I can say the Arc Ultra is the best soundbar the company has ever developed—and one of the best soundbars currently on the market.
Moreover, from my perspective, the Sub 4 is designed to deliver an audiophile level of performance. The integration of the sub with the soundbar is seamless and together they create a musical listening experience that is just as adept at reproducing the nuance of an Edward Van Halen guitar solo, as it is recreating an immersive audio dogfight scene from a war movie without compromise.
If anyone desires a state-of-the-art home theater and whole-house audio solution, there’s no better place to start than the Arc Ultra soundbar and Sub 4 powered subwoofer.
ABOUT THE AUTHOR
Bob is an audio enthusiast who has written about consumer electronics for various publications within Massachusetts before joining the staff of CE Pro in 2000. Bob is THX Level I certified, and he’s also taken classes from the Imaging Science Foundation (ISF) and Home Acoustics Alliance (HAA). Bob has also served as the technology editor for CE Pro’s sister publication Commercial Integrator. In his personal time beyond his family, he’s studied guitar and music theory at Sarrin Music Studios in Wakefield, Mass., and he also studies Kyokushin karate at 5 Dragons and Brazilian jiu-jitsu at Binda Brazilian Jiu Jitsu.
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