I'm putting together an HD system and I want to use apogee converters, specifically two AD16x's and one DA16x. I believe I need the optional HD cards for the DA16x's for direct connectivity to the 192's. I'm just a little confused on how they connect to the 192. As I believe I need 2 Digital 192's i/o boxes, one for the 32-DA in, and one for the 16-AD out. I think that means I need to purchase two 192's and then purchase another 2 digital cards for one of the 192's, as well as 3 HD cards for the DA/AD16x's. I'm not exactly sure how they interface together, but that is what I want, and would appreciate any help on this matter. Also I'm looking at the "Antelope Audio Isochrone OCX" as my master clock as well as their clock distrobution system for sync. How does it compare to the apogee big ben? Thanks for your help, it is greatly appreciated!