The current pre-release of the client ("pioneer" in the version) is only compatible to itself. So you can only play with other testers. Please be aware!
Thank you all for your help, @magge, @deletethis, @Sprouto, @Zokora and @arma473. I will play around once more with my sound settings, config, etc.. Should anything useful appear, I will let you know.
Cheers
