Oh don't get me started on this topic. OK, I started it...fair enough. Let's just say this is one of those things that is oft-talked about and rarely done, or at least rarely done "correctly." I think there is a fair bit of "naked emperor" around this topic, but that's likely to start a firefight. Let's just say it (NOT having any acoustic treatment, that is) hasn't stopped me getting any voice over jobs.
Anyway, here's an article talking about it that you don't need a science degree to understand.