Passively bi-amping, that is using two amps for one speaker (and removing the jumper straps on the back to create two independent inputs) where both amps receive the same, full range input signal (which I suspect is what is being described above), is a complete waste of time, space, electricity, and expense. It has no audible consequences, in fact it might actually be detrimental if the two amps don't have
exactly the same gain factor to the tenth of a decibel. The added cost would always be better spent buying, for example, a more powerful
single amp, rather than buying two amps for "passive bi-amping". [That more powerful single amp scenario could at least play more loudly before distorting, or could be said to have "cleaner, less distorted peaks".] All that passive bi-amping does is make one's amplification
doubly expensive and requires more wires; retailers and amp/wire vendors therefore have
no problem recommending it.
Active bi-amping, on the other hand, where there is an electronic crossover in addition to the two amps, which each receive different signals,
is quite useful in many cases and all of us using powered subwoofers are employing a version of that.
Edited by m. zillch - 12/1/12 at 8:46am