According to https://github.com/AsahiLinux/docs/wiki/Feature-Support there's at least partial audio support for every machine except the models introduced so far this year, using the 3.5mm output. The built-in speakers are still disabled by default while they work on the software required to drive them at reasonable loudness without burning them out. It's not clear to me whether audio over HDMI works for the models where they already have HDMI support.