When logged as root, I can access a sound recorder (not sure what package it is but it displays in help about gnom-sound-recorder 2.26.0) and record/playback audio. Similarly I can access an audio mixer (package xfce4-mixer) and select the volumes per each audio channel. Lastly I can run audacity -with which I have other problems but it does not complain-.
When I log as a regular (non super) user, if I launch the mixer it will complain: GStreamar was unable to detect any sound device. Some sound system specific GStreamer packages nay be missing]. It may be also a permission problem. If I launch the recorder it will complain: Your audio capture setting are invalid. Please correct them with "sound preferences" under the System-Preferences menu. If I launch Audacity and press "record", I get: Error while opening sound device. Please check the input device setting and the project sample rate. Lastly, VLC play movies w/o sound
Thank you in advance for your help
If someone more got this problem, you can try see the permission, look at /dev/mixer and confirm user:group to root:audio, if not, do it
chown root.audio /dev/mixer
then, logout and login.