Why the sound works only when logged in as root
 

Why the sound works only when I'm logged in as root?
When I'm logged in as regular user the volume control is crossed out and when I'm trying to use it I get following message:

The volume control did not find any elements and/or devices to
control. This means either that you do not have the right GStreamer plugins installed, or that you do not have a sound
card configured.

But I have the sound on the motherboard and it works fine when
I'm logged in as root (Volume Control VIA 8235 (Alsa mixer)
A GNOME/GStreamer based volume control application 2.14.2) -also it shows another option Realtek ALC655 rev0 (OSS Mixer)

What should I do so I can have sound when I'm logged in as regular user also?

Thanks

Perhaps there is a permission problem. Check the read and write bits and owners for such device nodes as /dev/dsp, /dev/timer, /dev/control, /dev/snd/*, etc. How this works varies from distro to distro. E.g., you might have owner root and group owner audio (with both owner and group getting read-write access) in which case you must add your user to the audio group.

Thanks, it worked by adding the users to the audio group.