Is there an accepted best practice(assuming two way speakers); use each amplifier for each channel or use one amplifier for the bass/mid and one for the treble? Thanks
Woofer/mid consumes more power than the tweeter. Best to use one amp for the treble, and one of the same brand and model line, but twice the wattage, for the bass/mid. The voltage gain is the same, so they are matched in level already. For example, an Adcom GFA-535 for treble and a GFA-545 for the bass, inputs connected by a Y-adapter.
Take your point though thinking more about something with same two power amps e..g. Audiolab 8000A with two 8000S. Thanks
Thinking about it a different way the equal power point is 300Hz, so Bi-Amp with two amplifiers of equal power and cross over at 300Hz; although this probably assumes a 3-Way speaker