rigid fiberglass covered with material. Looks good and is much more absorbent than foam.
Good but Cheap Treatments for Flutter Echo
I have a small listening room (11x12). With careful placement, Roomlenses, and velvet drapes covering the main window, I have managed to make it sound pretty good. My only major remaining problem is that the room still has a lot of flutter echo. I am looking for good economical treatments to solve the problem. Thanks.