How to design a high end crossover…

I’d venture to say that someone that does this for a living on the high end easily has $20kmin stock parts that they know well to do this. Many good to better caps cost in excess of $300, and the quality of those is a total crap shoot when it comes to a final design.

It doesn't need to be that complicated. Every designer has a "house sound" as I've heard it labeled. The actual electrical values often play an even more important part in the overall voicing of a speaker, than the quality.

Matching drivers that play well together (pardon the pun) is the very first step, before you even slice up the signal, to get a well resolving cohesive and dependable voicing.

Anti-phase measurements between crossover points (slopes obviously) where the drivers are at their best sounding are a good key way to get them to seamlessly blend across the frequency range. The argument that one driver alone that can do it all, that argument has merit.

Even DSP, requires knowledge of where to cross the drivers, if a fully active approach is to be undertaken. To me, it's the driver interaction, before the crossover is even implemented to shape the signal the drivers are fed, is the key to high end.

You can use relatively cheap components throughout, even the drivers to some extent, but if they won't play well together, if one simply won't vanish into the overall sound and reveals itself with colouration - your crossover cannot possibly win. DSP, fully active, with a crossover or not, driver matching matters.

Is this guy joking?

This is why a speaker is good or not. IMO, the hardest thing to accomplish is High End Audio. It is v far from just selecting the best components. It takes an artist to integrate drivers, crossovers and enclosures. To make the final speaker sound like music is rare.
For an amateur to accomplish this and, even, professionals with years of development.

Add 1/5 of excellent bourbon, branch water, natch.

Is this guy joking? 

Anyone with a fifth (or even 1/5) of excellent bourbon under his belt, yeah, I think he is joking.

Well, I didn't drink the whole bottle!

But yes, joking a bit.

First time in years I worked on a project and was surprised to look out the window and see the sun was rising.

I new one XO designer that would tune each XO to the cabinet and drivers he was using. The left and right crossovers very seldom looked alike. When the drivers were pulled and matched top to bottom and left to right as close as his staff could get, they would load wire and seal the drivers.

The Passive XOs were point to point mounted to 3/4 pre formed MDF or HDF boards. He used two LPads and parallel quasi 2nd order for a 3/4 way.

Here is the real trick, he would put an untuned xo in, position the speakers in the same place every time and take tone burst readings.

He would add a small cap in the band pass to one side only, and normally unwind and remove a small amount on a hand wound inductor (made from a real dry 1/2" dowel and hand wound copper wire 20-18 ga) It had 16-20 raps. He would remove 3-5 wraps on a dowel, and retest the DB levels. That is how he balanced the DB level in the BP and lower or raise the pass side with a small cap of the same quality.
It’s not a bypass cap (super expensive), it’s a trim cap normally a long life poly or something.. It act differently, the same with the inductor.. It’s for trim ONLY doesn’t effect the SQ just the tonal balance..

THAT is how I learned to TUNE an XO. Making one it’s not rocket science but, you really need to be able to TUNE and know HOW to tune your work for a SOTA audiophile quality XO.. Production crap who cares..

The guy could build and tune 3 pairs of XO in a night, after spending all day selling, ordering and talking to customers..

The staff would ready the call in orders on the spot.. or paint the inside with sound coat or black hole or the different wire or wool vs fiberglass in the mids. 3 guys I think Brian C, was 1. RIP.

I stopped in after work 100 times, he would be there trimming OXs or making them or writing an article.. or getting ready for CES. the soldering iron he used, you could have soldered gutters it was so big.... no kidding.. ;-)

Regards