For privacy reasons, the OpenBSD team disabled audio recording for all devices by default in the kernel. This can be toggled on/off with a simple sysctl change, without rebooting.
sysctl kern.audio.record=1 # enable at runtime
echo kern.audio.record=1 >> /etc/sysctl.conf # set at boot
Details:
- OpenBSD 6.4
- sysctl(2) - OpenBSD manual pages
- Audio recording is now disabled by default in OpenBSD | ZDNet