If you're planning on using this for floated floors, pipe insulation won't work. For optimum isolation, the pads you use on floated floors, or speakers for that matter, should be compressed by about 15%. This gets tricky for unknown materials, expensive for known ones. Auralex sells these "U-Boats" for bedding 2x4's in under a floated floor, but the cost can get carried away pretty quick. Other acoustic companies sell rolls of rubber pucks separated by webbing, that you just roll out and build your floor (either concrete or wood, depending on your dedication/budget - One alternative I'm considering which would cut costs but be a bitch to figure out the loading for 15% compression, is "horse mat" material. It's available at animal supply places that sell tack and feed, etc - it's a 1" thick re-gurgitated rubber mat, usually 4 feet by 6 feet. It can be cut with a skil saw. My plan for testing to see what percentage of compression is, would be to build a "test floor" maybe 1 x 2 feet, find something heavy (100 pounds or more) like barbell weights, and try various amounts of weight/pad contact areas until you found what weight/surface area gives about 15% compression. You then would have to calculate what the entire floating room would weigh with all equipment in it, do the math to find the contact surface area required, and spread this out over the floor joists evenly. Remember only the surface of rubber in contact with the 2x4's counts. Sound like fun? Me neither... Steve
