Sound defaults to external USB for me as per https://www.openbsd.org/faq/faq13.html#usbaudio
$ dmesg | grep uaudio0 uaudio0 at uhub3 port 1 configuration 1 interface 3 "Creative Technology Ltd Creative BT-W4" rev 2.00/28.38 addr 5 uaudio0: class v1, full-speed, sync, channels: 2 play, 1 rec, 3 ctls audio1 at uaudio0 $ rcctl get sndiod flags -f rsnd/0 -F rsnd/1 Pull the device and sound switches to notebook speakers. Replug and SIGHUP sndiod to use USB again. Works great. However, detach USB during explicit playback to it, e.g. $ AUDIODEVICE=snd/1 ncspot crashes sndiod(8) rather than playback just stopping instead of switching. Using USB alone ('sndiod -f snd/1') and device defaults ('ncspot') does not crash when unplugging during playback. Minimal reproducer (DEBUG='-g3 -O0' build, otherwise backtrace is all ??): $ doas obj/sndiod -d -f rsnd/0 -F rsnd/1 & [1] 92393 $ aucat -i /dev/zero -f snd/1 [unplug] snd1: switching to snd0 sock_close: not on list snd/1: audio device gone, stopping [1] + doas obj/sndiod -d -f rsnd/0 -F rsnd/1 Abort trap (core dumped) $ doas egdb -q obj/sndiod /var/crash/sndiod/92393.core -batch -ex bt [New process 575012] Core was generated by `sndiod'. Program terminated with signal SIGABRT, Aborted. #0 kill () at /tmp/-:2 2 /tmp/-: No such file or directory. #0 kill () at /tmp/-:2 #1 0xc8e16c0748c54a75 in ?? () #2 0x000005340e83dbce in panic () at /s/usr.bin/sndiod/utils.c:138 #3 0x000005340e839308 in sock_close (f=0x5340e842720 <slot_array>) at /s/usr.bin/sndiod/sock.c:183 #4 0x000005340e838fe3 in sock_exit (arg=0x5340e842720 <slot_array>) at /s/usr.bin/sndiod/sock.c:389 #5 0x000005340e829ff6 in dev_migrate (odev=0x536ddacb9c0) at /s/usr.bin/sndiod/dev.c:1392 #6 0x000005340e8357c3 in dev_sio_hup (arg=0x536ddacb9c0) at /s/usr.bin/sndiod/siofile.c:545 #7 0x000005340e8309d8 in file_process (f=0x5369435e420, pfd=0x79a16362a238) at /s/usr.bin/sndiod/file.c:289 #8 0x000005340e831059 in file_poll () at /s/usr.bin/sndiod/file.c:433 #9 0x000005340e838341 in main (argc=0, argv=0x79a16362a778) at /s/usr.bin/sndiod/sndiod.c:745