@audio2design --
Time I picked up on this:
Why are you going on about something that 99.9% of audiophiles have no interest in doing, and 9/10 of the remaining 0.1% are going to screw up?
To begin with most audiophiles seem to have no concept of active-as-separates as an option for hi-fi use, let alone the sonic results produced here (unless you assume all of the 99.9% supposed disinterested audiophiles know what they’re turning their back on and that’s the basis of their claimed disinterest?), so an introduction into its existence and possibility of successful use seems prudent - not least coming from someone with several very positive experiences of this solution that trumps most passive and (bundled) active set-ups that have been auditioned, regardless of price.
On the face of it your stance here sounds more like wanting to instill discouragement (and protecting your own business) than a level-headed assessment on the interest in and potential of active-as-separates as a DIY approach. 1-2/10 mayn’t achieve greater results, but if a higher percentage instead of those 0.1% that remain interested would break the mold of their hi-fi dogma, unawareness, prejudice, or other and invest some time into active-as-separates, then we’d see a wider and very different playing field that would seriously challenge the established norms of passive configuration and the existing bundled active approach, and one that would as well bring with it even more tweaking possibilities than the passive set-up - not to mention the all-in-on active package.
I am very cognizant of the DIY speaker community. There is some great craftsmanship, and some very good mid-level speakers, but at the top end, I can’t say I have heard much.
The best active-as-separates systems I’ve auditioned distanced themselves from most of the best passive set-ups I’ve heard as being a cleaner, less smeared, more resolved, transparent, coherent, and dynamically uninhibited sounding package.
That you keep repeating "Digital Cross-over" like it is the be all and end all shows how large the gap is between the average DIYer / probably most DIYers and truly professional designers working on advanced active speakers. It is not simply a matter of getting some amps, even expensive ones, and a DSP and playing with digital crossover implementations, and no, I don’t care how long you listen to it, you will never achieve a very good design without complementing that with a lot of measurements, and again, most DIYers have fairly basic measurement capability for advanced speaker design. I know ... pretty much the same techniques, but better S/W than what I was using to DIY 20+ years ago.
Most "truly professional designers" work to create bundled, all-in-one active speakers, and while I’ve auditioned a few excellent sounding iterations here, ATC and Grimm Audio being perhaps the most noteworthy examples, I haven’t found them to better, or even fully approach the best DIY active-as-separates systems I’ve heard, likely for other reasons than their specific active configuration. I couldn’t care less about the work, dedication and claimed sophistication that went into these bundled, preassembled and -developed actives by said professionals when what I’ve actually heard hasn’t convinced me of their supposed merits, except named examples.
As an outset IT IS about simply getting that quality digital XO hooked up and extra amps and cables all connected, preferable on a smaller secondary 2-way speaker set-up to experiment with, and then work one’s way around the basics. I didn’t take me long (i.e.: mere minutes) to figure out the potential of active-as-separates and how it would come to eclipse its passive iteration, even with initial filter settings, and from then on it’s about fine tuning with the aid of measurements, hours of listening with the input and help from friends and a lot of trial and error/exploration with filter settings and their influence on the sound. Getting rid of the cross-over on the power side of an amplifier and instead letting the amps see their respective drivers directly is in itself of significant importance, both in regard to letting the amps work at their fuller potential (effectively minimizing the need for amp prowess here) and bypassing the sonic bottleneck a passive cross-over, not least a more complex one, is, for a sonically less degradable XO option prior to amplification.
The implementation of a design I was involved in required a custom amplifier topology that you cannot buy off the shelf. The techniques implemented go beyond simple digital cross-over design and are beyond almost all DIYers as it would be rare to find that cross disciplinary expertise. That is not even getting into things like finite element analysis to optimize bracing or complex acoustic field simulation to optimize the lenses. The drivers were not off the shelf, but optimized for our drive/control methodology. Again, not available to the DIY community.
Conversely I’d level at you: you stress the implementation of non off-the-shelf items "not available to to the DIY community" as if to signal exclusivity and something we as DIY’ers can only dream of attaining - unless of course we indulge in your narrative and buy your product. Haven’t we heard that song before. It’s a trait claimed by other manufacturers out there, and by and large - as heard in-the-flesh - it hasn’t made me appreciate the sound of those products more than others. Too many factors of implementation are at play to single out that one contribution as anything of outright significance.
The DIY’er into active-as-separates has the option to optimize and go tweak galore on all product category fronts, and as well go all-in with regard to accommodate physics and a pre-existing, passive speaker package - not to mention what can be learned in the process.
Don’t get me wrong, there are some great DIY designs out there, but as you move into active designs, the complexity of what is possible just went well beyond "DIY". Its a lot more than just a digital crossover and amps (and drivers, and box, and ...)
You’re evading an important point: with the complexity chosen in the active-as-separates set-ups I’ve heard, an outset that could as well be favorably chosen by others, the results are great - not to say among the best I’ve ever heard. They better their passive iteration (if they were such to begin with) by a noticeable margin, and in general outperform a range of much more expensive set-ups I’ve heard - mostly passives, because all-in-one active set-ups are relatively far and few between. Whichever way you want to bend it we’ve gone beyond "... just a digital crossover and amps (and drivers, and box, and ...)" and in doing so created impressive sounding set-ups, so we get the gist.
Which is to say: DIY’ers/audiophiles can certainly tackle an active-as-separates approach if they set their minds on it, and in the process produce great results. Whether that complies with your methods and ultimately to your liking is another matter, and not really relevant it would seem.