Looking for high quality 3-way design


I would appreciate advice on a good 3-way design along the lines of a ribbon tweeter with Accuton C79-6 midrange, maybe SEAS Excel or Revelator bass.
I see a lot of 2-way and 2.5 way designs, yet also read that the mid-range is most important and is ideally covered by a single driver with no XO from 400Hz to about 4,6, or 8 kHz.

So, I am a bit confused as to why I don't see more 3-way designs compared to, say, MTM. Would prefer closed or vented to dipole.

I am happy to go with active XO as part of the overall solution.

Thoughts/ideas ?

Thanks, Jack
IMO, the reason is that a 2-way should cover most of the signal that you're trying to reproduce. Ideally, you'll have a mid-bass that covers the important region 60/80Hz-3/4kHz (pretty much all the vocal fundamentals and most of the musical fundamentals). Then you'll have a tweeter that covers most of the high stuff, and a subwoofer (or 2) for the really low stuff.

But, then, doesn't that make it a 3-way anyway?

I've generally got this set-up using 2 'base modules' (Lambda 12" in sealed boxes) and using my Elac 510s (or whatever DIY flavour of the month I'm currently using) as the main speakers. A subby (eventually) will be used to put holes in the wall on the really big explosions - but not yet:)

As far as the MTMs are concerned, IMO it's to allow a fairly small mid-bass to be able to handle the signal at a reasonable level (there's no substitute for cubic inches). MMtMM even better...
A few reasons I suspect, one of which is complexity, and the difficulty of integrating drivers well. Also, there aren't many really good dedicated bass and mid-drivers available (though you can find them if you look around). A good way forward might be simply to use 3 mid/bass drivers, one of which handles the mids, and two in series which handle the bass, a la the Revolver RW45 and Monitor Audio Silver S8. World Audio Design used to have some good 3 ways on their site, but since Audax discontinued the drivers, the designs were removed. Anyone out there got them? They should be adaptable to other units.