4. Select from the above and put them in the order you want in the file __/etc/modprobe.d/alsa-base.conf__, by assigning an index from -2 to 2, marking the preferred device as the lowest number.
As an example if you have two devices and want the one that says usb because that is your headphone, on __/etc/modprobe.d/alsa-base.conf__ you will put:
2. On Firefox open __about:config__ and enter "__/dev/snd/__" under __security.sandbox.content.read_path_whitelist__ and __security.sandbox.content.write_path_whitelist;/dev/snd/__.