There's one other thing we've not mention on the 1820 - and until I got one, it didn't click. It can manage mic or line/inst on each of the first 8 channels - BUT - it uses combo connectors, which totally messes up using a patch bay because you cannot remote all your XLRs to sockets on the patchbay, but retain aother 8 designated line. Physically inserting a jack sets the hig level input and inserting an xlr provides mic level. I guess where you have two 8 way units, the idea is not really to 'patch' but to give you 16 XLR sockets to plug mics in conveniently, rather than jacks. Mine is in a rack and I'm already thinking of doing this because already connecting things is a pain. However - I need the mix of line and mic, which messes it up. I might experiment with the XLRs and the pad and see if theyre happy with this - and if so, make up a panel with XLRS and jacks, wired in pairs? My other two interfaces (Tascam and Presonus) have them on the front.