skype stopped emmitting sound

[robert rottermann]

Hi there,

since yesterday skype on my ubuntu 15.04 boy stopped emitting any sound.

Sound still works fine in other programs.

I probably have apt-get updated things as I do that regularly but have not 
installed anything new.

I reinstalled skype but still the same.

In the list of devices in skype I found only "virtual" as possible selection.

any idea what I can do?

thanks
robert