If you are using a Zobel network to correct the impedance of a driver with a parallel network to work with the passive crossover, then it is not needed for the digital crossover. If it is due to the driver impedance loading on the amp for feedback stability, then the Zobel network would still be required.
I may not have been clear with my question, which I apologize for. I have heard digital crossovers in systems (at shows etc) and still find the "sound" wanting. I am attempting to ascertain the reason.
My first comment is, I have never heard an amp directly connected to a driver have a flat response. The driver frequency response varies with frequency, is impedance related. A zobel attempts to flatten not only the impedance, but also the frequency response over a broad frequency range. This means extremely minute changes, not only in the analog realm, but in the digital realm as well.
For general information, the digital crossover would have to simulate a capacitor and resistor combination (simulate impedance change VS frequency) and be variable to extremely minute levels. I shall give you an example.
I am matching the amplitude level my full range driver to amplitude of the woofer in my test speakers, to 1 part in some 200,000. I am adjusting the full range driver zobel network resistance by less than 1 part in 20,000. Are the very best digital crossovers capable of such minute adjustments? Just asking.
Lastly, what about the need to AD as well as the DA when working with analog? Has those distortions been taken into account? (Distortion is anything that corrupts the music.)
Cheers
Steve