Quote..I'm not sure what hardware brand or version of OPNSense you're running, but this also happened to me. I was just tinkering with it today. I have a Lenovo M720q Tiny as well as a M715q Tiny. The beep can be heard on the M715q but not on the M720q..
root@router:~ # ls -al /usr/bin/beep
-rwsr-xr-x 1 root wheel 10088 Nov 24 23:26 /usr/bin/beep
# This version interprets tone-length integers as millisecond values, and it
# works (makes beep noises) on my system.
root@router:~ # ls -al /usr/local/bin/beep
-r-xr-xr-x 1 root wheel 7584 Jul 21 16:21 /usr/local/bin/beep
# This version interpretes tone-length integers as centi-second values, and it
# DOESN'T work (no sounds) on my system.root@router:/usr/local/sbin # diff opnsense-beep opnsense-beep-ORIGINAL
69c69
< /usr/bin/beep -F "${NOTE}" -D "${DURATION}" -g 100
---
> /usr/local/bin/beep -p "${NOTE}" "${DURATION}"
# The -g 100 argument optionally boosts the output volume to 100%, which is necessary
# for the tiny speaker in this system.root@router:~ # cat /dev/sndstat
Installed devices:
pcm0: <Realtek ALC235 (Analog 2.0+HP/2.0)> (play/rec) default
pcm1: <Intel Kaby Lake (HDMI/DP 8ch)> (play)
No devices installed from userspace.