HI J:
Well, from a simple question about paint to general room acoustics.
Rives is a pro at this and has lots of hands on experience so my $.02 isn't much. But I think he is right on re asking about how much fiber board you want to put in the room and pointing out that it might be best to paint some of it. I would like to hear more from him on practical points of "how to." I'll throw a couple things out if nothing more than to get a response.
I agree with Rives re the over damping. I know some folks actually like the dead anechoic chamber sound but not me. Usually the rationale is that you are listening to direct sound but I just do not care for it.
A few point to consider.
-You will need additional devices to deal with the major low frequency resonances and even the mid frequencies. You can break down how sound acts in a room by frequency. Lower frequencies act like waves, higher like rays, and there is a middle section that is really neither and both. The size of your room determines the frequencies where these regions are. Your fiber panels will not do it all. The bottom line is that, like Rives said, you will want some additional devices in the room to control the frequencies that your fiber panels do not absorb. Stuff like the devices talked about in the Risch site Sean mentioned.
-There are ways to calculate all this (what your room reverberation time is, total absorption at different frequencies, ect.....) but I have not been that lucky with that approach. I use the calculations to get Âball park figures and then experiment. I really recommend the book I quoted above (F Alton Everest ÂMaster Handbook of Acoustics). It is really well written and a good $35 spent. It is a little work reading and has a lot of good info. On the other hand it is really clearly written and you do not have to be a physicist to take a lot away from it. ItÂs easier to read than it is to tear down fiber board!
Room calculations seem to have limitations because all speakers have different off-axis response and some Âcohere 6 feet from the speaker and some you need to sit 15 feet away, ect. Read the articles by Toole below and what Linkwitz has to say about a speaker's radiation pattern and room interaction. I tend to think of it as room/speaker interaction and every speaker (or at least each type of speaker)has it's own particular characteristics.
Also the furniture plays a big part as you can see from Rives excellent site. You can, however, fairly easily calculate the resonant frequencies that will dominate your room and tune traps for those as Rives pointed out.
My approach would be to get an idea about the additional traps / diffusers you might want and actually place some of those in the room before you line the whole thing with fiber board. This way you arenÂt going to extremes in one frequency area before you even start in another. Just seems more balanced. Then start placing the fiber board. You can get a good idea about the traps needed and where the crucial areas typically are for placing the board from the Everest book or the Risch site.
Lots of work but the room is 50% of the sound. I hope you can take your time on the project because itÂs worth it. You know how it takes some people many years to tweak a system to taste? I think it can take a lot of time to tweak a room too. Don't be in too much of a hurry and don't do things you can't undo w/o lots of work.
Anyway...that is all too much advise for not even knowing the dimensions of your room! Take it for what it's worth. Let us know how you do. If not in a post drop an e-mail. I like to learn form other's in this area.
If you are going through all the trouble of a dedicated room you might find these sources interesting.
Two of the best web sites on audio acoustics that I really found helpful.
Art LudwigÂs site.
http://www.silcom.com/~aludwig/Linkwitz Lab.
http://www.linkwitzlab.com/rooms.htmA few articles on line.
Two articles by William Dudleston:
http://groups.yahoo.com/group/Thunderstone_technical/files/Room%20Acoustics/Dudlestone%20-%20Acoustical%20Sense.pdfhttp://groups.yahoo.com/group/Thunderstone_technical/files/Room%20Acoustics/Dudlestone%20-%20Stereo%20Effect.pdfTwo articles by Floyd Toole:
http://groups.yahoo.com/group/Thunderstone_technical/files/Room%20Acoustics/F%20Toole%20Room%20and%20Speaker%20Working%20Together.pdfhttp://groups.yahoo.com/group/Thunderstone_technical/files/Room%20Acoustics/F%20Toole%20Maximising%20Loudspeaker%20Performance.pdfLet us know how you come out!
Cheers,