The newly launched Sonos Arc Ultra boasts an impressive configuration of 15 amplifiers and 14 drivers, enabling this Dolby Atmos soundbar to deliver 9.1.4 channels of sound, as stated by the manufacturer. This marks a significant upgrade from the original Sonos Arc, which featured an 11-driver, 5.1.2 setup. While the increase in surround channels (from 5 to 9) and height channels (from 2 to 4) is noteworthy, the singular “1” at the center of the Arc Ultra’s channel arrangement may have the most substantial impact.
This middle .1 refers to the low-frequency effects (LFE) channel, traditionally managed by a dedicated subwoofer if available. This channel is crucial for creating the deep, immersive rumble we often associate with cinematic audio. Although the original Sonos Arc manages low frequencies reasonably well, it does so using the same drivers responsible for mid-range sounds. These drivers are not specifically tuned for LFE, which is why many Arc owners opt to purchase a Sonos Sub or Sub Mini, adding up to $799 to their overall system expense.
The Arc Ultra introduces an innovative “Sound Motion” driver, which features a four-motor, dual-membrane woofer. This design incorporates two membranes in a space typically allotted for one, enhancing its ability to produce bass. According to Sonos, this unique configuration provides the Ultra with “twice the bass” compared to the standard Arc.
The Sound Motion driver is built on proprietary technology that Sonos acquired through its purchase of Mayht, a Dutch audio company, in 2022. A 2020 article from audioxpress.com explains the mechanisms behind Mayht’s driver innovation.
What does “double” entail in this context?
Sonos elaborated to Digital Trends, stating, “When we refer to the Arc Ultra producing up to twice as much bass as the Arc, it indicates that at maximum volume, there is 6dB more low-end output. This enhancement means that the Arc Ultra can deliver richer dynamics and a more realistic sound experience.”
Interestingly, both the Arc and Arc Ultra maintain a low-end frequency response limit of 50Hz. While the bass won’t go lower in the Ultra, it will be amplified, providing a more impactful experience.
To gain further insight, I spoke with Hilmar Lehnert, who has extensive expertise with both Sonos and Mayht. He spent nine years at Sonos, serving as the audio technology manager for the last two years there. Following his departure in 2020, he advised Mayht until the acquisition.
I inquired whether directing lower frequencies towards the Sound Motion driver would enhance the performance of the other drivers. He agreed with confidence.
“Absolutely,” he confirmed. “This minimizes the movement required from the mid woofers, allowing their design and tuning to focus on enhancing spectral and spatial performance.”
Can the Sound Motion driver take the place of a subwoofer? Not quite. While it would be revolutionary if a single soundbar could fulfill both roles simultaneously, we aren’t there yet. Nevertheless, Sonos’ new driver technology is certainly closing that gap. For some users, it could transition the perception from merely wanting a subwoofer to genuinely needing one.
This isn’t unfamiliar territory for soundbars—other brands have made strides, such as the impressive bass output of the Klipsch Flexus Core 200—but it marks a milestone for Sonos soundbars. This advancement could help justify the Ultra’s higher price point.