To add to Craig's comments, it is the high currents and voltages and heat liberated from the voice coils that cause part specs on the traditional crossover housed inside the speaker cabinet to drift. When those specs drift, amplitude, phase and transient response are all negatively impacted and the effects are audible.
As Craig said, the voltages and currents in the DSP-based digital filter are a lot lower. The signal voltages the DSP deals with are no larger than about 7 Volts and currents are much less than an Amp...likely one tenth of an amp. Contrast that to over 100 Volts and 40 Amps (sourced from an amp) that an analog crossover has to deal with. On top of that load, the voice coil of an HP driver reaches 200 degrees C. Some of that heat gets excreted through the sphincters, some is radiated off the glorious aluminum dust caps and the remainder is trapped in the cabinet and affects the performance of the crossover components (and the voice coil itself). These nasty effects don't take place inside the DSP box.
The DSP can also bring benefits that Axiom isn't currently exploiting. For example, by monitoring the temperature of the voice coils, the digital filter coefficients can be adjusted to compensate for the rise in resistance of the coils (as much as double) due to temperature.
As for the ADA amps, within the present industry paradigm, they are a very good value particularly for multi-channel.
