BR, the type of "passive" biamping that you're describing doesn't appear to be of significant advantage in any living room. Using a Y-connection to send the front left-right outputs to two amp channels each, of course sends a full-range signal to each amp channel. What is sometimes called "true" biamping requires a separate crossover(often electronic)before the amp channels so that each gets only the specific frequencies wanted. It's then necessary to bypass the crossovers in the speakers. Note that passive biamping in no way doubles the available power(as is sometimes suggested), it merely has separate output transistors feeding from one power supply and driving the separate sections of the speaker. Two 100 watt amp channels remain at 100, not 200, watts, and one can't "borrow" from the other in the unlikely situation that more was needed.
