Looks like an OpenAL crash. I turned off sound after this and it hasn't happened again.
Code:
Thread 4 Crashed:
0 com.apple.audio.OpenAL 0x015268a3 CAMutex::Lock() + 31
1 com.apple.audio.OpenAL 0x0152f241 OALBuffer::ReleaseBuffer(OALSource*) + 29
2 com.apple.audio.OpenAL 0x015274d8 BufferQueue::RemoveQueueEntryByIndex(OALSource*, unsigned long, bool) + 68
3 com.apple.audio.OpenAL 0x0152bec8 OALSource::RemoveBuffersFromQueue(unsigned long, unsigned int*) + 684
4 com.apple.audio.OpenAL 0x0151bd80 alSourceUnqueueBuffers + 261
5 0x0031ea9e SoundStream::update() + 206
6 0x003121aa SoundManager::internal_thread() + 186
7 0x006aa8a8 ThreadedClass::thread_proc() + 184
8 libSystem.B.dylib 0x988a585d _pthread_start + 345
9 libSystem.B.dylib 0x988a56e2 thread_start + 34