X-over question

Some speaker manufacturers advocate low order slopes in their (passive) speaker designs in order to preserve phase relationships. Conversely, the new digital room correction/x-overs (DEQX, Tact, Lyngdorf) allow very high order slopes because the digital crosses allow this approach in the digital domain - purportedly without impacting phase. My question:

What about active, line level X-overs in an analog, bi-amped configuration. Can anyone describe the relationship between slope and phase for this type of x-over?

Thanks,

Marty