I'm not a speaker designer, but I am an engineer so take what I know with several grains of salt.

I'm pretty sure you want to aggresively filter out frequencies that fall outside the crossover frequency. Whether we're talking about filtering high-frequencies from a bass driver or low-frequencies from a tweeter, if a driver sees frequencies well outside its performance curve it will probably distort, fail outright (ouch) or generate intermodulation distortion (IM) which results from trying to produce widely disparate frequencies at the same time (or some combination of all three).

For example, you will generally get significantly better performance out of your main 2 speakers if you don't feed them tons of bass. (Unless your main speakers are designed for this). Probably better to send all those subterrean signals to a well-balanced sub (say a Vandersteen 2wq).

I'm sure you will get a more accurate answer from the speaker building hobbyists and crossover filter designers. People who know a lot more about first and second order filters than I'll ever know. (If I've flubbed this one severly I'll apologize to Carl Marchisotto, John Dunlavy and the other speaker gods later)

Good luck,

Jim Burnes