Requirements for CAPlayThroughMBS?


I’m trying the CAPlayThroughMBS class but it looks like even the example won’t work. I tried on a 2013 MacBook Air (MacOS 10.15), a Mac mini (M1, MacOS 12) and a 2012 iMac (MacOS 10.15).
I don’t get any error (and can actually hear the output device being “activated” if it was idle), but I can’t hear any signal. I tried many combinations, as well as adding “a.volume=100” in the example.

Is the CAPlayThroughMBS used for earlier OS versions only (deprecated)? Is the example still working for someone these days?