I have been looking at some receivers lately and found that they perform a crossover function when you select bi-amp for two of the outputs. The wiring inside the speaker should be separated after the speaker posts. I looked inside a set of speakers at my buddies house and the crossover for the sub was connected to the bottom posts and the mid-high crossover was connected to the upper posts.
I've been in electronics for quite a few years and don't pretend to completely understand balancing, harmonics, half power or 3dB points with regard to music, but if you crossover at the amp, you may not have a high end bi-amp setup but you do separate the channels. Especially if you have a high current receiver with overhead room.
The only crossover function in a receiver is the LFE to sub and the speakers set to small.
Here is a sample crossover.
Removing the jumpers makes the crossover look like this.
So when you connect the two amp channels to the two set of terminals, one amp goes to the tweeter high pass which takes very little power.
The other goes to the woofer low pass circuit, which takes almost all the power.
Even in three was designs, for some reason the manufacturers set it up that the top terminals just go to the tweeter and the lower ones to the bass and mid. That always seems obtuse to me as if it was split woofer/mid tweeter their would be a power advantage. But the arrangement is almost never set up that way.
In active biamping the amplifiers are connected directly to the loudspeaker drivers, there are none of the components shown above.
The crossover is and active powered circuit between pre amp and the power amps. However this can not be a generic circuit and has to designed the same way as a passive one, to provide the correct transfer functions for the drivers involved.
We get this question again and again to the point we are just plain tired of it.
