Acoustic treatments are often used to help improve the acoustics of a room by taming "flutter echoes," "room modes," and other problems which arise from a room's dimensions and construction.
Although a variety of treatments are available for commercial use, they tend to be quite expensive. After some research both online and in print, we came across several sources for DIY acoustic treatments using rigid fiberglass panels and simple frames. These are often referred to as "bass traps," although the ones that we're focusing on have a fairly wide rage of absorption. While commercial versions are available for almost $100, we were able to make these panels for about $24 each.
We can not take credit for this design, but have combined several people's ideas into a step-by-step guide. Most importantly, we give credit to Ethan Winer's excellent article, Build a Better Bass Trap
For more information, check out the good folks in the acoustics forum at recording.org