I'm sorry I mistakenly wrote "bi-wiring" instead of "bi-amping". I have already "bi-wired" the speakers using a single stereo amp which has two pairs of speaker outputs. I was questioning the vertical "bi-amp" diagram in the manual which goes like this:
Amp # 1 ..................> Left speaker
Left +/- ....................> mid-tweeter cable
Right +/- .................> bass cable
---------------------------------------------------------------
Amp # 2 .................> Right speaker
Right +/- .................> mid-tweeter cable
Left +/- ...................> bass cable
My confusion is about the bass cable connections which appear to be reversed. Sorry if I'm missing something obvious.