Homemade sound panels

Be careful not to end up with a room that's dead in the upper frequencies and still highly reverberant in the bass. It's easy to over-absorb short wavelengths, but very difficult to absorb long wavelengths. Lining the walls with a lot of foam panels is unlikely to yield good results.

In my opinion, as a ballpark general guideline diffusion panels usually make more sense than absorption panels at mid and high frequencies. Absorption makes more sense in the bass region.

Duke
dealer/manufacturer

I made panels for my room and they were most effective. There are plans out there describing type of damping material, fabric covering, size of panel etc. There are specific materials to use. It's worth the effort, your room acoustics count as much as the gear you use.
Larry

Before you make your own panels, have a look at these. Excellent price, and I have been happy the results in my listening room with four of their 2 x 4 foot wall panels.

http://www.atsacoustics.com/

While I have the ones that Goheelz mentions, I happen to like the ones from this company a lot better.

http://www.acoustimac.com/