For those who are interested in filters, specifically crossover filters, there's a way to visualize filter behavior and interaction (both amplitude and phase) with nothing but your Apple computer and Smaart v.7.

In addition you need AU Lab, Soundflower and a plug-in called CrossoverUnit. Daniel Lundberg is behind this brilliant solution. Click here for his excellent blog on how to set this up.

The CrossoverUnit plug-in allows you to model all single slope filters like Bessel, Butterworth and Linkwitz-Riley up to 8th order (48 dB/oct.). In addition it also offers complex slope filters like Chebyschev and Inverse Chebyschev used in e.g. Meyer Sound's Galileo and Callisto processors.

Unfortunately CrossoverUnit doesn't support elliptical filters a.k.a. Cauer filters, also used in e.g. Meyer Sound's Galileo and Callisto processors. Fortunately there's another plug-in called EngineersFilter.

EngineersFilter is VST plug-in that offers the same filters as CrossoverUnit and in addition elliptical (Cauer) filters. In order for it to work you need to setup a VST host on your Apple computer. The first document below describes all the necessary steps to get this working. The second document is an extensive comparison of both plug-ins.