I finally fixed the looping sound crash!! I used to get the crash at least 6 times per map and yesterday I played for 3 hrs straight including 3 vs matches with no crash! I had tried all the suggestions posted on the thread but had no results. What I did was instead of adding mat_queue_mode 0 in the console, I entered +mat_queue_mode 0 in the launcher options. I right-clicked left 4 dead in the "my games" under the steam program. I then went to properties and went to launch options. I added the line there and it worked. Maybe with the game loaded, there is no way to disable multi cpu rendering? The pre-launch option worked for me