phusis,
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?
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.
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.
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.
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 ...)
