The funny thing is, I don't find the math or cross-over design work hard at all. Where my dreams of DiY speaker building come to a halt is working with the materials to build the cabinets.
That said, if I were building my ultimate speaker, it would be tri-amped, with the amps strapped to the enclosure. It would take a digital feed. The cross-over work would be done in the digital domain to maintain phase alignment perfectly. Then three separate DACs feeding each of the power amps. Or even better, those "power DACs" which take PCM and use it to drive the class D amp directly.
