Now, you're beginning to get it.
So back to your origional question: Is it worth it?
I had a pair of power pigs and an old 100 wpc amp. It was a very strong 100 watts though but I auditioned another pair of monoblocks that were much more refined and had great imaging. Unfortunately the monoblocks didn't have nearly the bass depth and slam. No problem, just use all the amps, right?
The good part was that the bass crossover was at 90 Hz. If it was any higher, it would be more difficult because the hearing is more sensitive in the midbass.
Still, not that simple. First, the old amp was inverting. Easy fix; reverse speaker wires to bass. Then the gains didn't match so I went down to the doohicky shop and bought a 5 KOhm carbon potentiometer, a box and some female RCA's. Wired that up and twiddled for weeks. It was better but not quite right. Every time I changed the volume, I had to adjust the gain. Every CD had to dialed in. Even then, it always seemed bloated around the crossover point. Went back for a different doohicky. This time, it was a wire-wound pot. No better. Another thing that happens with multiple amps is ground loops and hum. Just another part of the learning experience.
Started looking at active crossovers and what would be involved. They ain't cheap. While I knew the crossover point, I could not find the slope of the passives in the speaker. Considering that each order (1st, 2nd...) adds 90 degrees of phase and and the speakers were designed to be coherent at one of those, I thought I should know. Turns out that wasn't relevant because active X-overs have a choice between 24dB/octave and 48(8th order). I also started to learn something about notch filters that I could not account for. In the speaker, the x-over was soldered on a circuit board. This seemed like brain surgery at the time and I could have ended up with a pile of parts. Now, with a bit more knowledge, these aren't simple problems but nothing insurmountable.
There was one other alternative, or so I thought. I bought a dual, 23 position rotary switch (attenuator) and a bag of resistors. This ain't cheap either and it certainly wasn't easy but Mr. Doohicky was happy.. Soldering 46 tiny resitors on a tiny switch is not fun. The ones that can be bought preassembled had a higher range than I needed. I chose all the resistors between 1K and 3K and added a DPDT switch that added another 3K (paralleled 6K), 6K or nada. Much better. No more fiddling with it, at least not after the first month, and no bloating. It also gave a great way to adjust the bass to my tastes. The DPDT switch turned out to be unnecessary.
Granted, an active would have killed that passive parasite and made the speaker much more efficient, I still have to wonder. I was planning on building a set of speakers from the ground up with an active x-over, because I'm convinced that's the best, but a sweet deal popped up.
The next set of speakers had an active x-over/bass amp from the factory. Well, semi-active, but let's not go there. It has controls for gain, low-pass, hi-pass and phase. Hooked it up with those little monoblocks because I didn't exxpect the midbass and up to take much power. Lots of trial and error with the settings and location. Changed from RCA to XLR. Different preamps, even built one myself. Learned that phase is more than quarter turns (90 degrees) and could hear within 10 to 15 degrees on either side and went for the middle.
No matter what I did, there was a dip at the crossover until a friend brought over his behemoth SS amp and the dip went away. I also tried with tube amps but not my taste. You could say the little monoblocks was a mismatch of character. The 1600 watt bass amp had a lot more. I was expecting to buy a new amp for the speakers but not quite so soon. Now, I've got three behemoths and it all worked out beautifully. By the way, bridging does work for some amps.
If you want to know see how complex it can be to make a versatile x-over, check out Wisdom's "Brain".
Did you expect a short story?
