Originally Posted by edva
Because of the (normally) close-micing, and because of the (normally) low to moderate volume of a vocal (e.g. not loud enough to excite resonances in the space), the direct-to-reflected ratio of a vocal recording is (normally) very good, so (normally) acoustics don't matter AS MUCH as they can with other sources. Which is not to say they don't matter at all.
The human voice having a conversation is around 60db, that's a lot louder than you would think and singing in many cases is quite a bit louder than talking. Now consider the distortions caused by early reflections (this causes the effect that many people mistake for "digital harshness") it doesn't take very much to have a negative effect on sound quality.
You might also consider why so many people spend all that time and money to build a vocal booth. The space you record in is very important. Now if you have a relatively large bedroom with carpeted floors, shelves, a bed, curtains, upholstered furniture and optimal proportions, you might find that you're sitting pretty. Don't get me wrong though, I totally support expanding ones mic locker, but it's important to have perspective. New shiny gear is often NOT the solution to unsatisfactory results.