I think we can help you, by the process of elimination you describe, but your description of each change you make needs to be clearer and more specific.
For instance, what's the difference between swopping the monoblocks and hooking them up to opposing speakers?
In each instance we need to know what is hooked up where, and if there is any noise from either speaker.
For instance, when you hooked right mono to left speaker, did you also hook left mono to right speaker? Was there noise is either channel? Which speaker cable did you use?
For instance, what's the difference between swopping the monoblocks and hooking them up to opposing speakers?
In each instance we need to know what is hooked up where, and if there is any noise from either speaker.
For instance, when you hooked right mono to left speaker, did you also hook left mono to right speaker? Was there noise is either channel? Which speaker cable did you use?