Does something happen when speakers face each othe

Yes, if one or more of the speakers is "out of phase", it will cancel out a lot of the sound. Out of phase means one or more of the speakers is wired differently than the others. So, the speakers should be wired + to +, - to -. But if you have one of them wired + to -, it is out of phase and will cancel out all of the duplicate information from its partner speaker if they are pointed toward each other.

I would check your wiring from the amp outputs to the speakers very closely. If one is incorrect, that is your problem.

Enjoy,

TIC

Sorry to hear that your speakers suck.

When I was playing around with my own designs for matrix multichannel, I discovered that a rear speaker operating out of phase with the fronts could very greatly boost low frequency response. Think of it this way...you are exciting the room air in a push/pull manner rather than single ended. The boost frequency depends on the distance from front to back speakers, and on relative phasing, although I didn't experiment with phase.

Frankly I doubt that an inactive speaker will soak up much sound. The cone area is very small compared with that used for room sound absorption devices, and the cone material is not particularly absorbant.

Another thing to check out, if you have a separate amp or processor for the rear channels it may be inverting phase (or the front may be). If the electronics are shared between front and back this is not an issue.