My lastest weekend project: a huge bass corner wedge made from rockwool. It's 48" tall and the triangular dimensions are 35"x24"x24". I only have this on one corner right now and I'm in no hurry to do another one - The stuff is such a pain to work with. I wanted to take these all the way to the ceiling but there are some architectural anomolies...
I was positive I could hear tighter bass from my most well known test songs, but I haven't done the measurements to back that up yet, so it may be Experimenter Bias.