It can be done both ways with great results. I go back and forth between 2 and 4 amps depending on which pair of speakers I'm using. To me and those who hear my system it is fantastic. Nothing messy at all using 4 amps. Even on Tannoy Legacy Arden. It's a game changer. Check out my system.
Anyone prefer horizontal bi-amping their monos?
Just got monos a week ago, digging them mightily. I know the answer to my question is 'just try it' which I will someday.
Just curious if others have done this A/B, & their take.