6,12,18,24db Xovers: General Q's

I've learned a lot reading this site, but I haven't found a discussion yet on the pros and cons of using different crossover networks. I have gotten the sense (possibly the wrong sense) that Linkwitz-Riley 24dB crossovers are preferable if your drivers are suitable. My guesses to the reasoning is that you have better power handling by keeping drivers in a tighter range, and the frequency response differences between mid/tweet will conflict less the less you overlap. Am I on the right track?

I've also gotten the sense that active are preferred over passive because passive networks are both inefficient and introduce possible unwanted filtering into the line, depending on the quality of the components. How exactly do active crossovers work compared to passive? I have a basic understanding of how passive crossovers work based on my physics courses and a basic electric circuits course. I definitely don't know how active ones work, nor why they are called active.

Right now I am also mostly referring to car audio, although in principle I guess it should apply the same. I have an Eclipse CD8053 head unit (some on here might be familiar with this model). It has a built-in 3-way 24-band (maybe not the correct terminology, I mean there are 24 preset frequencies you can set the cut-off to) active crossover with options for a 6,12,18, or 24dB slope. From what I've read it is a pretty good active crossover, and I prefer the sound over the passive second order butterworth that was included with my speakers (Polk MM6:Link). The included x-over is set at 3.5KHz, but my deck only has options for 3.15 or 4KHz, I have it set to 4KHz with a 24dB slope. I am of course bi-amping my speakers to do this, hmm.. that would be obvious. :xeye:

I am also curious on if it is at all reasonable to attempt to adjust the 10-band parametric equalizer without a good RTA. This head unit is so powerful, I really want to make good use of the features.

If there is even just a link someone can provide that will answer all my questions then that would be great.