Originally Posted by cctvtech
So, explain it for us dumb folks.
Do some reading. There are plenty of threads regarding bi-amping here in these forums. And sorry if I've offended you. That was not my intent. Frankly, in the context of your post, I was startled that you thought the power was simply additive. You do not seem "dumb".
Biamping a speaker with 2 100watt amps is not the same thing as driving that same speaker, conventionally (mono-amped), with a 200watt amp. At all. If you feed a tweeter 100watts and a woofer 100watts, in a passive bi-amp situation, you are not now driving the speaker at 200watts. The tweeter does not receive the 100watts. Nowhere near it. Tweeters do not require nearly the wattage that woofers require. Likewise, if you conventionally wire (mono-amp) a speaker to a 200watt amp, the woofer receives considerably more than 100watts of power. Considerably more. A speaker's crossover does not simply split the power evenly between the woofer and tweeter. One of it's functions is to properly parse the power, as is necessary and as designed, between the two. And even when passively bi-amped, the crossover still parses the amount of power between the woofer and tweeter identically to the way it would were the speaker not bi-amped. In other words, you do not use a whole bunch of the power of the amp that is being used to power the tweeter when you passively bi-amp. One might even say that you waste it.
The power is not additive. If you bi-amp a speaker to 2 100watt amps, you are not now driving it at 200watts. I can't give you an exact figure, as it is going to vary from speaker to speaker, and the math is not at all so straight-forward, so let's say for simplicity's sake that it would be more like driving it at 110watts.
Now, there MAY be other benefits of passively bi-amping that do not have anything to do with increased power. But these are arguable. And only barely so. I think the consensus would be that you'd be better off buying a more powerful amp and conventionally wiring a speaker than passively bi-amping with lesser powered amps. Everything else identical, a 200watt per channel amp, conventionally wired to a pair of speakers, is a much better choice than passively bi-amping the speakers with 4 100watt per channel amps.