Link without clutter: https://teddit.net/r/Qubes/comments/tnib7k/guide_on_using_a_usb_audio_device_with_qubes_41/
Upd: the above link doesn’t work anymore. Try this instead: https://old.reddit.com/r/Qubes/comments/tnib7k/guide_on_using_a_usb_audio_device_with_qubes_41/