Well, the unknown pointer error may be Dolphin reaching 2 GB of memory. Open task manager and see if something strange happens the next time you play. But I have no idea what you mean by laggy audio. If you mean the audio is delayed by a significant amount, then that shouldn't happen in the latest development builds. There is a ~50ms audio delay in order to make games sound smooth when computers are barely getting full speed in 25 fps games. If we made it any lower, people could get full speed in some games and still have audio stuttering.
If it's something worse than that then I can't reproduce your issue at all and have no idea what's going on. For it to work one run and not the next; maybe the crash set it back to OpenAL or anything other than xaudio.
Edit: I'm an idiot, you're on a mac. Do you have pulse audio or anything like that? Or is it just OpenAL? You can disable the time-stretching by setting Latency as low as possible. You can try tabbing to make the game go so fast that video/audio catch up.
If it's something worse than that then I can't reproduce your issue at all and have no idea what's going on. For it to work one run and not the next; maybe the crash set it back to OpenAL or anything other than xaudio.
Edit: I'm an idiot, you're on a mac. Do you have pulse audio or anything like that? Or is it just OpenAL? You can disable the time-stretching by setting Latency as low as possible. You can try tabbing to make the game go so fast that video/audio catch up.