I get no sound output from R1b4 under VirtualBox 6.1.42 on a 2012 MacBook Air running macOS 10.14.6. Any ideas how to fix this?
The answer(s) in this forum may point you in the right direction - I don’t use VMs myself, not for a long time now, but it is likely a setting you need when starting it up, as was USB, in the old days… 
Try switching the sound card in VM settings; another thing I’ll keep saying because I’ve found VirtualBox 7 to not be so great with Haiku is to try setting it up in UTM, which runs Haiku a lot better.
Hi, maybe I didn´t look at the right link in that page, but from what I saw there UTM seems to just work in iOS ( iphones and ipads ) . No mention there ( that I could see ) of it running in MacOSX computers.
Is it one of those cases where it is not documented but works, or needs some special options when installing ?