I am building a 2nd Order XO for a 2-Way speaker. I have it pretty much figured out, but I am not sure if I will need a Zobel or not. At this time I have the speakers dialed in at a XO frequency of 520 Hz. I am using an active XO (24dB) and it is the best setting. I would build a 4th order, but simply put, it is too much $. At 520 Hz both drivers are at their flattest impedance curve. For one driver, Markaudio CHR70.3A the rise in impedance starts shortly after, and for the woofer, HiVi M5N, the rise in impedance starts shortly after also. Since, at my XO frequency of 520 Hz my drivers are at their almost flat impedance curve point, do I need a Zobel, or not much needed in this case?