If you're using Pulse Audio, there is a fix for the stuttering or even missing audio in the cutscenes of Saints Row 2:
1) open the properties of Saints Row 2 in your steam-client, select local files and browse local files
2) locate the file "saintsrow2" (it's a shell-script) and do a backup of this file
3) edit the file "saintsrow2" and add
right before this line:
./saferun.sh ./saintsrow2.i386 "$@"
NOTE: this does NOT fix the missing music in some radio stations! The problem with this is some forgotten converted audio files in the port of the game.