In macOS Sequoia, several Apple apps have gained a new HDMI Passthrough feature that enables a Mac to send an unaltered Dolby Atmos audio signal to a connected AV receiver or soundbar.
The new functionality appears in various places in macOS 15, including Apple's TV, Music, and QuickTime Player apps. Apple says turning on the option lets users "Play supported audio in Dolby Atmos and other Dolby Audio formats using HDMI Passthrough when connected to a supported device."
The feature is likely to be welcomed by users who connect their Mac to an external device that supports Dolby Atmos, such as an AV receiver or soundbar. When conected via HDMI cable, the device will be able to decode and output the full immersive Dolby Atmos audio as it was meant to be experienced by the creators, while sending any accompanying video signal to a connected TV.
It's unclear whether this option will be included in tvOS 18, but given that Apple has made it a system-wide feature in macOS Sequoia, there is a good chance we will see it come to Apple TVs in a future update. Both macOS Sequoia and tvOS 18 are currently in developer beta, with public betas expected later this month, followed by a general release in the fall.
Source: Macrumors