[Jens Eklund]

Originally Posted by PhillyFolk

you could potentially modify most any room, making them "acoustically neutral," simply by nailing all of the old "oriental" type rugs throughout the house to the walls ...

Just in case someone actually believes that this is the case:

Carpets absorb a very limited range: the highest frequencies. If used excessively, all you’ll end up with is a room with a very uneven decay time in the frequency range and still “boomy” and untreated in the lower range, which is not a good thing. You normally need lots of absorption in the lower range and often little or no absorption in the higher range (if recording room with enough volume). Even if too small for a “live room”, carpets are still usually not beneficial due to the restricted absorption range.