I posted this awhile ago, but didn't link the graph, so I'll try it again because this was surprising. In a quest for a flat bass FR, I decided to see what effect a small movement in main speakers made. This is a 2 channel stereo setup. These plots are sine waves, rat shack meter corrected. No sub, just stereo moniters with 75Hz line filters. The ONLY difference was moving the speakers from a foot from the wall to 4 feet out-NOTHING else was changed. I was amazed at the huge impact of a small speaker position change. There is a room mode at about 55Hz that is in both plots (much worse without the 75 Hz filters). But a deep, wide trough centered at 80 hz shifted to 65 Hz and became much shallower just by moving away from the wall a few feet. The plots are about 16 dB different between 75 and 95 Hz. A lot of people harp about the importance of room effects and placement importance, but I had no idea how right they are.