Ok, yesterday I wrote a thread on Gearslutz about bass traps. In my home depot I found only 2 kind of absorber: - some kind of Isover panels, 2" thick, 145kg/m3 density - big rolls of fiberglass, very soft, 1" thick, 40kg/m3 density I asked wich one is better to build basstraps and broadband absorbers and they said me the less dense. Said that they started explain me that a 2"-4" basstraps don't do anything below 100Hz. If I want some kind of absorbtion below 100Hz I need 20"+ basstraps O_O Is it true or they are maniacs as usual? I've never seen 20"+ basstraps (only if they are some corner traps). Do you advice to use the less dense for basstraps and broadband absorbers?