1) Traditional passive speaker connection: AVR speaker wire straight to the SX-8300 just like 10,000 other passive speakers.
2) Active bi-amp (for the Advanced audiophile, more rare): AVR LFE output (Denon X4000 has dual independent LFE, others may need a Y-splitter) to external amp first, then connect speaker wire from the external amp to the bottom speaker binding post of the SX-8300. Then connect the AVR L/R main speaker wire to the top binding post of the SX-8300.
Thus, if you don't have an external amp, you cannot actively bi-amp the SX-8300 nor any other speakers. Active bi-amp requires the use of an additional amp. One amp is for the tweeter & midrange (which do NOT require a lot of power) and one amp is for the bass (which requires a lot of power). If you have an AVR with one LFE, you would need to buy a Y-splitter cable or adapter.
If all towers were designed like the RBH towers, then most audiophiles could actively bi-amp their towers, instead of passively bi-amp.
Which leads to the question -- why the heck don't they?
Does it cost too much money? Surely $22K Salon2, $25K B&W 800D2, and $20K KEF 207/2, etc., could justify the cost.
I was also thinking, if you actively bi-amp the SX-8300, the AVR could easily power the tweeters and midrange drivers of the SX-8300, which most likely require 10% of the total power, and the ATI AT1802 would actively bi-amp the bass drivers of the SX-8300.
So the AVR connects to the top speaker binding posts of the SX-8300, and the AT1802 connects to the bottom speaker binding posts of the SX-8300. The AT1802 is 270W into 4 ohms @ 0.03% THD, so 1% THD would probably be about 300W. The SX-8300 is rated for 100W-400W.
Of course, if you want to go a lot cheaper, the Dayton SA230 (230W) amp would also work. You would need 2 Dayton amps. Retail is $200 each, but our friend could get it a lot cheaper.