Hello,
the SB16 emulation of VirtualBox 6.x. does not work correctly with OS/2. The sound card is visible and can be accessed, but playing any sound stops prematurely after half a second or even less. Sounds shorted than this time are not played at all.
Attached is a log with setextradata <Name-of-VM> "VBoxInternal2/Audio/Debug/Enabled" "true"