they all go in via different I/O pathways... Audioengine A2s are for casual youtube and stuff so they go in via the regular stereo input... the Audioengine A5+ need a bit more power so i have a Headroom Micro DAC via USB to a Micro amp that the speakers connect to... the M-Audio's are via USB as well and the Bowers & Wilkins MM-1s off to the right are via USB to the Macbook Pro
I might have overlooked it, but where are the MM-1's? I really dig this pair but I cannot justify to my significant half to shell out $500 for it.