FrankC, Biamping will "relax" the load on your amps while reducing the stress on your speakers. This will provide sonic benefits that stretch across the entire realm of frequencies.
There is vertical biamping; by driving one amp(mono) per speaker,or horizontal biamping; using a stereo pair of amps. One amp drives the bass section of both speakers while the other powers the mid/highs.
As I stated, I am using two totally different types of amplifiers and this may upset purists. I've always liked the sound of tubes, but do enjoy the biasing, testing and re-tubing of the larger amps. The 100 watts per side of my ARC 100 mk3 are more than enough to fill my room with gorgeous sound while the low end of the ML 333 is deep and resolute. I at first bought a Krell FPB 300 to do the job but I was bothered by the Krell's "sound". This mixed combination does just fine for me.
my humble output, Richard