Standing waves

Each frequency put out by your speaker has a different wavelength determined by the speed of sound in air. A wave reflecting back and forth between two parallel walls will reinforce itself if the nodes of the wave coincide with the room boundaries. Thus your room selects a set of frequencies coming from your speaker to reinforce. If you sit at the PEAK of a reinforced standing wave (also called a mode) that frequency will appear louder. If you sit at a null of the standing wave, the frequency will appear to be sucked out.

So EVERYONE listening inside rooms with opposing parallel walls has a standing wave problem

This is an interesting topic. I have a Mac 2000 amp, Mac C100 pre, ECM-1 CD player with Nautilus 803's. Pretty good stuff, but those standing waves. Talk about nulls and modes. My room is 11 X 12 and is kind of small, but comfy. I treated the room with Echo Buster bass traps, diffuser and absortive panels. These helped a bunch, but still problems with placing my one chair in the room and speakers to avoid areas of total lack of some frequencies and over emphasis of others. Any ideas where to place my chair vs. these speakers?

Amwarwick: Check a thread entitled "Near field listening and speaker placement" In the various posts of this thread are references to several useful websites which address exactly the question you have asked

Will check this and thanks Judit.

One foot from the wall??? Say it isn't so. I assume since your room is 15' wide you mean the ATCs are 1 foot from the front wall. If you can I'd say get them at least 2 or 3 feet from the front wall and toe the speakers in a bit. A pair of Mana stands may also help. Also, make sure your listening chair is at least a couple feet from the back wall, as that will also reinforce bass at the listening position.

If all else fails, TacT room correction will certainly take care of the problem, and many others as well. Best of luck.

Tim