USB microphones with FreeBSD-CURRENT

Jan Beich jbeich at
Sat Mar 28 12:45:31 UTC 2020

Graham Perrin <grahamperrin at> writes:

> I can't get web browsers to recognise USB microphones.
> USB output (e.g. to my headphones) is OK.
> USB input (e.g. from the microphone part of the headphones) is not.
> Any suggestions?

Firefox uses "pulse-rust" cubeb backend *by default* if "pulseaudio"
package is installed. getUserMedia is supposed to preset a dropdown menu
to select a microphone. Make sure pulseaudio actually recognizes the
desired microphone e.g., debug via "pactl list" and "parec".

I don't have a mic but, looking at the code, only pulse-rust or pulse
backends on Linux/FreeBSD support selecting non-default audio device.
It maybe possible to use other backends but if audio device used for
output and input are different that'd require routing defaults which can
be done via config file (e.g., ~/.asoundrc) or externally via virtual_oss.

> pcm3: <USB audio> (play/rec) default
> pcm4: <USB audio> (rec)

Are these distinct physical devices?

> hw.snd.default_unit: 3

Have you tried using 4?

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