What about the bass sounding "muddy," as being too close to a wall. I don't know if it's true or myth but I remember reading too close to a wall thickens and makes the bass sound muddy as opposed to tight. I would like to have my Submersives as close to the wall as possible for the simple fact that they intrude less physically on the room.
Muddy can mean different things. Using this chart, it refers to frequencies in the 250-450hz range.
Regardless of the frequency range you mean, I would look for peaks, elevated response over a wide area or very slow decays in the region in question.
Edited by jim19611961 - 10/8/13 at 2:42pm