Right then, I am now going to take the plunge and attempt to make some DIY absorbers for the side walls of my small HT (garage conversion). Can anyone tell me which products would be the most efficient absorbers? 1) fibreglass loft insulation on a roll 2) fibreglass cavity wall insulation slabs, (like fibreglass roll but is designed to be installed inside a cavity wall (usually 8' x 4' x 2" thick slabs I think) 3) rigid insulation slabs (like kingspan-the stuff that fits nicely between roof joists and is about 2 to 3 inches thick I think) 4) some foam 5) any other stuff I haven't though of! The plan is once I have decided which of the above to use, to build wooden frames to size and then cover with some acoustically transparent material or fabric. Voila! I have read most of the posts on this subject but I just wondered which type of insulation product to buy!