This sound fix was for an older client version, and worked brilliantly for me. I don't think it would work with this version however. Try this, in the Planeshift Launcher go to Audio, tick Enable Sound, then choose OpenAL for Sound Renderer, not Software. Log into Planeshift and hopefully you will have music, sound effects etc.
I'm not sure if OpenAL is included as part of the client now. If not google it for your Operating System.