The answer gave me what I wanted; what to check. I checked those things and they were correct, and had been correct. The problem remained.
Then I muted one channel that was on "solo," and then "solo"ed it again. Voila! The sound returned. Not only that, I have more control over volume now. *Weird*
So it's all solved, and the answer gave me exactly what I wanted. But the answer didn't solve the problem. So...?