A few months ago i bought new Axiom M80 speakers for the front side of my HT.
The Energy 22 Ref. speakers i was using before were sent to the back for surround duty.
I put them about 1 foot behind me and next to the side walls, facing each other.
Wow, did i have bad sound!
It seems there was interference between the Front Left and Rear Left speakers in such a way that it seemed to produce a kind of flutter echo at some mid frequencies.
This interference seemed concentrated in my auditory canal and was loud and very unpleasant.
At first, i changed the front speakers' toe-in with no effect.
After thinking about the problem for a while, i changed the angle of the back speakers to face the back wall so i would not get direct sound from them, but mainly reflected sound from that back wall.
Result: very good sound.
I would love to have an explanation for the reason i got this interference from those speakers - mainly on the left side, and also is there any way to solve this problem and still keeping the back speakers looking at each other instead of being pointed towards the back wall.
The left side of the room has more sound absorbing material than the right side.
I used for a long time RS Minimus 7W speakers for surround, and never had that problem.
