Originally Posted by VirusKiller
Can you buy (conventional) amps that are optimised for particular frequency ranges?
Naim for the tweeters, Quad for the woofers...

Originally Posted by VirusKiller
Expecting a single amp to work well at all frequencies isn't necessarily reasonable, but I'm not aware of tweeter-, mid- or bass-specific HiFi amps.

I don't think it's unreasonable, the frequency ranges aren't that large.
As Ian states, the power requirements are different for each range, so if you are going active, you can use different power outputs for each drive unit (same gain though).
I don't think Meridian or any other manufacturer optimise frequency response; the only way to do this would be with an active crossover or by making a poor amp (poor power supply, high capacitance feedback etc.).

My take;

Passive Single Wire; OK
Passive Bi-Wire; No difference, sells more cable.
Passive Bi-Amp; No difference, sells even more cables and amps.
Active Bi-Amp; Now were talking...

For those that swear by passive Bi-Amping, I'll agree that it would make a difference in absolute SPL, especially if the power amps aren't that good, but you'd be better off buying a single larger amp, unless you're going to go fully active at a later date.

All the best,

Steve.