I have a "SoundMAX Integrated Digital Audio" and have been having this problem for many builds, all the way back into the Alpha. I had to wait until I was sure about the Beta 2 build to be sure, but it is still happening. In my case, it seems to start with just portions of the sound affects failing to play, then progresses to all sounds quiting.
Then a strange thing happened. The research "GNN" came up without the research music, so I sat there waithing for several seconds just to see if it would come up. I gave up on it and pressed the done button and the research music came up briefly in the transition from the research GNN screen to the other completions GNN.