No sound (Pi2)

In Audio settings there is message “no sound device”. Connection was made via HDMI-DVI converter if this is important.
And for some reason the whole system is freezing often (this is another problem).

DVI will give you video only (no sound)

OK, but I am not trying to get sound from HDMI. I use 3.5" jack for sound. Unfortunately there is no ANY sound device in Audio settings.

I believe you have to enable it by adding to config-user.txt the following…

dtoverlay=pisound
dtparam=audio=on
audio_pwm_mode=1

As for the freezing you would need to supply logs for anyone to have any chance to gain insight into why, although you might want to check to make sure your power supply and power cable is up to snuff as this is the most common issue with unstable RPi’s.