When Bi-amping is there change in sensitivity

In a passive bi-amp situation, where a preamp is feeding two power amps and the signal from those power amps are feeding a bi-ampable speaker where the connection between the bass and midrange/treble is removed, where does the excess signal go? The preamp is feeding the full frequency range to the amplifier, which is amplifying that full frequency range and feeding it to a speaker's woofer, for instance. What happens to the part that is above that woofer's frequency cut off range. Doesnt it just get absorbed in the crossover and turn into heat. If so, how does that result in a decreased load to the amplifier?

Applying the OP's situation, where he wants to use an 80 watt tube amp on top and a 500 SS amp on the bottom, where does the 80 amps bass power go to? If it still has to produce that power, just to get absorbed in crossover, then your speaker is limited to what your lowest power amplifier can produce at the bass frequencies, even though the speaker is not producing that power from that amplifier.

Usually, the point of using a lower power tube am with a higher power ss amp is to get the sweetness of tubes in the midrange and up, while getting the power and control of SS in the bass. Since bass notes require considerably more power for the same percieved volume, it would seem that the only way you could take advantage of the SS amps increased power is to direct frequencies before they get to the amp, so the tube amp never sees the bass frequencies. Then the tube amp can play very loud without clipping because the mid/hi range takes much less power than the bass.
Reading the posts above has got me to thinking about this, and my prior approach using passive biamping makes little sense.

Almarg,
"Keep in mind that power equals voltage times current (or less, if the load is not purely resistive). The crossover circuit that is in the mid/hi section of the speaker prevents low frequency currents from being supplied by the mid/hi amp and flowing into that section of the speaker. The near zero current means that the amplifier is delivering near zero power at low frequencies, even though its output voltage corresponds to the full-range signal.

Likewise, the crossover circuit in the low frequency section of the speaker prevents mid/hi frequency currents from having to be supplied by the low frequency amp, resulting in near zero power being supplied by that amp at mid/hi frequencies."

I dont quite understand how the crossover circuit prevents the low frequency currents from being supplied by the mid/hi frequency amplifier since the amp is being fed the full range and only after it reaches the speaker does it get split off by the coil used in the crossover. How does that coil draw off the low frequencies if they never get there in the first place? That is why I dont believe that biamping with the same amplifiers changes the sound other than perhaps some additional headroom for the mid/hi amp.

Since the amp is being fed the entire spectrum and amplifying it to the speaker where it is diverted by the crossover, where does that diverted energy go?

Get it now.