Bi-amping

+1 for both of the above comments. I've been multi-amping for many years. Started in 1976 with just bi-amp and will never go back to passive crossovers again. Good luck!

Always crossover at amplifier inputs. And, in my opinion get rid of the internal crossover in the speakers too.

You can bi-amp with the crossovers still connected in the speakers, no jumpers between speaker posts. Even without an electronic crossover at the amplifier inputs you will still hear a noticeable improvement in sound. With an electronic crossover at the inputs, you will see an even greater improvement due to limiting the frequencies each of the amplifiers need to reproduce, this saves power for the specific driver ranges. This savings is most noticeable in the mid and high frequencies produced. Keeping the speaker crossovers in place also adds a layer of protection for the drivers in the speakers. The way I'm doing it, bypassing the internal speaker crossovers, is dangerous for the drivers. However, for me, the reward in sound is worth the risk, but it is not for everyone. If you would like more details, feel free to PM me. What speakers are we talking about here?

I'm using a home built analog crossover with low-noise / high-speed op-amps. It's 24dB/octave, nothing very exotic. I started with TDM. There are many manufactures to choose from for a relatively low price. Many prefer digital crossovers, I'm just not one of those. TDM and DBX on the low end or Marchand and Bryston on the higher$. Even Behringer is decent from what I understand.