While a tapestry / carpet hung on the wall looks nice and tames high frequencies by absorbing them, it'll not reduce the room boom of lower frequencies that the original poster had enquired about - it's too thin and there isn't enough of an air space behind it.
If anything, hanging a tapestry carpet on the wall will reduce the high frequencies and throw the sonic spectrum further out of balance and exacerbate the room boom problem.
If anything, hanging a tapestry carpet on the wall will reduce the high frequencies and throw the sonic spectrum further out of balance and exacerbate the room boom problem.

