Maj, you say that "insulation" is going to be used for "bass traps". The problem, as Fred mentioned, is that simple absorption of sound by fiber glass or similar insulation material isn't very efficient at very low frequencies. There seems to be some enthusiasm on the internet for this type of installation which isn't completely in accord with acoustic principles. The literature indicates(e.g. Toole, Sound Reproduction, p.476)that to be effective at bass frequencies the insulation would have to be about 1/4 wavelength deep. The 100Hz wavelength is about about 11.3 feet and 20Hz about 56.5 feet.
Mechanically resonant membrane absorbers are more efficient at these very low frequencies and electronic equalization may be a more practical approach at these frequencies.
