It seems that trying to do so makes device reboot instantly - yet, it wasn't my test (as it don't own external sound card compatible with Linux). Could someone who performed those tests write with details what was done, and how results were looking? I'm quite sure, that - in case of user-error in configuring PA - gurus like joerg_rw could be able to help.

for beginning, even redirecting *whole* sound to another card would be good (doing it and going back to default could be automated by scripts). Unfortunately, AIUI, it was *not* achievable for reasons unknown, up to date.

/Estel