You can cast local Dolby Atmos files to Sonos using the Hi-Fi Cast or BubbleUPnP app.
https://play.google.com/store/apps/details?id=com.findhdmusic.app.upnpcast
https://play.google.com/store/apps/details?id=com.bubblesoft.android.bubbleupnp
Sequence Pink Noise 7.1.4 file: https://bluewindy.solaris.usbx.me/filebrowser/api/public/dl/A6CxJEFW/downloads/Sequence%20Pink%20Noise%207.1.4.m4a
Apple Music Link : https://music.apple.com/kr/album/sequence-pink-noise-7-1-4/1748110988?i=1748110990&ls
At first I was skeptical about this, because the Dolby Atmos indicator didn't appear in the "Sources" section of the Sonos app. So I decided to play 7.1.4 test tones. I adjusted the overhead volume while the overhead test tones were playing, and it actually worked.
On the other hand, when I streamed 7.1.4 test tones from Plex, which is provided by the Sonos app, the overhead volume adjustment did not work. So Plex does not support Dolby Atmos Cast.
If you plan on using the BubbleUPnP app, do the following in settings:
1. Click Renderer Settings in Preferences.
2. Disable FFMPEG decoding.
3. Disable Mime-type check.
And to the Sonos dev team: Please add an indicator to see what type of audio is being cast from the source.
