Solved Which conf file do I place default sound device to start at boot?

[toorski]

I found and plugged-in my old USB Logitec soundbar speaker. I discovered the device in 11.3-RELEASE with

cat /dev/sndstat

as
pcm6: <USB audio> (play)
I did:

 sysctl hw.snd.default_unit=6

Now, the sound works. But, I forgot which conf file do I need to update to start the USB sound at boot as default?

 

[toorski]

I think that I found answer to my question. I missed the:
"where n is the number of the sound device to use. In this example, it should be 4. Make this change permanent by adding the following line to /etc/sysctl.conf:"
in FreeBSD doc sound set-up

Edit:
It worked!