Biamp question

Thank you all. I have not tried the st 100 by itself yet. Are you saying that not only is it stout enough to drive the bass on the legacy’s but that you also prefer the sound of st 100 over the a21+?

You do not need a crossover- just let the speaker do the work.

The crossover allows you to set the crossover frequency, adjust levels, and remove the unwanted frequencies from going to each amp. It's the most flexible setup.  

Buy-amping is an especially effective marketing tool for electronics manufacturers.  

At my current abilities I would be very hesitant to use an active crossover since I would actually have to get inside the speakers and disconnect built in passive crossovers in them. The nice 7 year Legacy warranty goes out the window and if I make a really bad mistake potentially a pair of $9000 speakers go south. I guess when I started this I was looking for an easy way to use these 2 amplifiers that would make a sonic difference without adding active crossovers and opening up my speakers. 

I have also read that when you go with passive biamping that since the crossovers being used are at the speaker level that the preamp still gives the speakers the full range of high and low frequencies. I can’t seem to wrap my head around that since one amp is going to hf and the other amp is going to lf. Seems like crossover of the speakers would prevent any upper frequencies from going to the lf and lower  frequencies from going to hf. Apparently the built in crossovers of the speakers cannot prevent that from happening in the same way active crossovers can? If that’s true is it because preamp sends everything and speaker crossovers can’t filter properly? And if that’s the case it would seem I would lose the implied benefit of the tube amp handling hf and ss handling lf. And I’m pretty sure I am the most confused person in the room right now.