Does something happen when speakers face each othe

Reubent...The difference is that I refer to speakers that are about 28 feet apart, whereas yours are one inch apart. 28 feet is half a wavelength for 20 Hz.

Yes, this is possible...even likely, if the rear speakers you mention are floorstanders. If this is the case, you have recreated and old room treatment tweak. The non-playing rear speakers are acting as bass traps.

Eldartford,

You may be correct in your experience, but an out-of phase pair of speakers that face each other (especially if close together) will cancel all of the duplicate information, leaving only the "difference" information.

Placing speakers out of phase and facing each other is an old trick that many people use when breaking-in a new pair of speakers. I've done it many times. You can turn up the volume much louder, but still get the same driver excursion because the duplicate sound is cancelled out.

Try it sometime if you want to see what I mean. Take your right and left speaker and place them facing each other. The closer the better (I usually have them about 1" apart). Reverse the wiring on only one speaker. It will produce a very much diminished sound. Oh yeah, if you can play in mono (the same signal to both speakers) it will be muted even more because there is no difference signal for each speaker, there would only be a duplicate signal. The duplicate "sound" is somewhat cancelled by the other driver that is moving in the opposite direction.

BTW, I don't really know why/how this is different from a speaker that is designed as a push/pull setup.

TIC

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.

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.