My hi-fi setup is a little.. um.. unconventional.
Source - Laptop usually
Receiver/Processor - Pioneer VSX-LX505
Now the Pioneer front pre-outs feed a miniDSP 2x4. I plan to upgrade this to either a MiniDSP Flex or a Hypex FA123. I'm still researching the best active crossover in terms of ADC and SINAD. Right now though, my old miniDSP 2x4 is pretty decent, and can handle a whole bunch of biquad filters I am throwing at it. It's a pretty aggressive sixth-order linkwitz-reilly crossover that no sane person would design.
Now the MiniDSP has two inputs, and four outputs. Someday, once I get the miniDSP upgraded, I would love to get four Purifi amplifers, or even just Hypex NCore. Right now though, the miniDSP feeds four analog surround inputs on a Harman Kardon AVR 225 I picked up off kijiji for $90. Now this thing is plenty powerful at about 50W per channel when four channels driven, but the main issue I initially had with it was one of some weird digital noise that I think caused the person to sell it. I diagnosed the issue and found the source of the noise was the video input card on the receiver. Since I didn't actually intend to use this as a receiver, I simply disconnected the video inputs and now the HK receiver is a functional four channel amp. It's not the weakest link in terms of SINAD despite being a surround receiver - the miniDSP is. I might be the only person with a $2000 receiver who uses it to driver another twenty year old receiver. I bet even the word receiver makes some audiophiles cringe.
Anywayysss, my speakers are something I built myself. The midwoofer is an Acoustic Elegance TD15M with Apollo upgrade, in a mass-loaded transmission line cabinet that allows it to dig prety deep with a shallow rolloff. It's crossed over to a Denovo BA750 titanium compression driver in an autotech SEOS-18 waveguide. As mentioned earlier, this is a 6th order LR filter :
centered at 850hz. So really, the compressive driver handles the vast majority of the midrange and treble frequencies.
Due to the tweeter's native response, this filtering is practically impossible with passive components. I've also got the drivers time-aligned, another thing that is very difficult to do passively, but a sinch actively.
Anyways, I know what you're thinking. A titanium tweeter diaphragm... probably has some ringing at high frequencies... you're not wrong. This tweeter has a significant breakup mode centered around 15khz. However - I, like most males over the age of twenty-five - am deaf above ~16khz, and my hearing is barely sensitive at 15khz... so I don't actually hear any of the consequences. Below the breakup frequency, this tweeter/waveguide combo sounds amazing.
Cost-no-object, I would love to replace the diaphragm with a beryllium one someday though. That would push the breakups all the way up above 22khz