Most of what I'm reading uses panels/bass traps. But some of the demo rooms here locally basically wrap all the walls in a solid piece of fabric with some sort of 1/4" or so absorbtion padding underneath. Sounds easier but is it cost effective? What materials do they use? Are those rooms too dead?
Thanks. 1/4" is only a guess, the rooms are padded all around and the question is more, this seems easier as you can't miscalculate where all the reflection points are, because everything is covered. Even if you went to 1" is this advised? Could you then add corner traps for lows? and what material would you use?
Most demo rooms I've seen are pretty poorly done. I'd be very surprised to see 1/4" of "stuff". More likely it's 1" ... and that is only a partial solution to the acoustics of a room. The fabric is to hide absorbers, diffusors and other items which do not lend themselves well to good interior decor.