Sonos introduces headphone linking for Ace Ultra headphones

The Ace Ultra serves as a hardware update over the original Ace, aiming to better integrate the headphones into the broader Sonos ecosystem. According to Trusted Reviews, the device is designed as an all-rounder to compete with top-tier wireless headphones, incorporating head tracking and a TrueCinema feature intended to create a spacious audio effect that mimics a soundbar.

Headphone Linking Technical Requirements and Setup

Headphone Linking relies on a new hardware and software architecture called Headphone Engine 2, which Sonos confirms is exclusive to the Ace Ultra. The system requires the headphones to be set up in the Sonos app on an iOS or Android device and connected to a local Wi-Fi network. Because the feature operates over Wi-Fi rather than Bluetooth, it is not functional for on-the-go use and can be affected by weak signal coverage within a home.

To activate the feature, users must opt into the Early Access program via the settings menu under the Headphones section, where they can select Link to your system. This process also configures TV Audio Swap if a compatible soundbar is detected. The system supports a wide range of Sonos products, including the Arc, Arc SL, Arc Ultra, Beam (Gen 1, 2, and Ultra), Era 100, Era 300, Five, and Move 2, provided they are not being used as rear surrounds in a home theater setup.

Audio Swapping and Content Compatibility

Users can move audio in two ways: through the Sonos app output selector or via a physical button on the headset. By pressing and holding the Content Key on the right earcup, the Ace Ultra targets the nearest compatible Sonos product to pull audio. To send audio back to a speaker, the user must be within approximately an arm’s length of the device to avoid accidental playback that might disturb others, according to the Sonos Community forum.

The feature supports specific content types, including music services initiated in the Sonos app or via Sonos Voice Control, local music libraries, and line-in sources. However, the Sonos Community notes that Headphone Linking does not work with audio started via Bluetooth, AirPlay, or direct music service control. The system also uses a high-quality compressed stereo stream, meaning lossless audio and Spatial Audio are not supported during linking sessions.

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Early Access Performance and Limitations

As an Early Access feature, Headphone Linking is currently in a refinement stage. Trusted Reviews reports that the system can be slow to recognize nearby speakers and occasionally fails to receive audio after multiple attempts. In some instances, the headphones may pull audio from the wrong device if two compatible speakers are in close proximity.

The system also imposes specific connectivity and grouping limits. Sonos documentation states that the setup uses a BLE connection that supports only one active listener at a time. If audio is pulled from a speaker that is part of a group, that group will disband and stop playing, as the system moves the audio rather than duplicating it.

Integration with Sonos27 AI Platform

The Ace Ultra and its linking capabilities are part of the broader Sonos27 AI platform. This framework is intended to increase automation and efficiency within the home audio environment, reducing the number of manual steps required to manage audio across different rooms. While current functionality focuses on audio swapping, the platform is designed for future customization and personalization across the Sonos ecosystem.

Cameron MacLeod, who leads audio systems for the Wearables/ Headphones team, stated that the priority for the Early Access release was establishing the fundamentals.

Our priority for this Early Access release was nailing the fundamentals: clean, reliable, high-quality audio streaming with Ace Ultra as part of the system. We built a dedicated WiFi connection for this exact purpose and put it through extensive listening evaluations to

Cameron MacLeod, Sonos Audio Systems Lead