Is it possible to have a room that is too dead? Could this ever be a good thing? I'm all for ambience and the reverbs that occur in rooms, but when people talk about deadening a room, how far is good enough/too far?
You do not want a room that is too dead. It will not give you a realistic perspective on your mixes. You will most likely end up using too much reverb. A good room is one that has a natural ambience that decays evenly across the audio spectrum.
A really dead room using sonex type stuff is really bad, because that stuff does not treat the low end, so your EQ perspective will be way off.
My theory is that it's easier to add temporary reflective surfaces than absorptive surfaces, so I made the room dead for tracking, and I have a bunch of big framed posters I hang as necessary to liven it back up.
A dead room is rightly named. You'll find that musicians don't like to play in one, and that they will constantly turn up the volume to try for the "life" they are used to hearing. Dead ain't good: controlled is best.
> Is it possible to have a room that is too dead? <
You got a lot of really good answers, and I'll add only this:
Small rooms are not very good sounding for mixing or recording. So if all you have is a small room that sounds bad no matter where you put the microphones and performer, adding absorption may be your only option. But it's a lot better when a room has some life to it.
For a good overview of these issues see the Acoustics FAQ, second in the list on my Articles page: