DSPs are quite common in car audio. Alpine PXA-H800, mosconi 6to8 are popular among enthusiasts. In the end, they convert the analog input to digital, perform crossover, eq and other operations and then convert back to analog using built in DAC. Ideal for average DACs that we find in car audio head units. But to home audio, we have much better options. I would still prefer good DAC -> active crossover/preamp -> amp -> speakers.
To start with, I am planning to install panasonic bottlehead headunit -> amp with active crossover -> quasi active speaker setup for my car.