I'm still on LA 6.3.1 from the Big Box, but in it there's a main menu selection under (I think) Audio called EXS24 Instrument Editor. Selecting it will bring up an Open dialog box. Navigate to the .assignatassignate file you want to edit and open it. You get the Editor window that Peter was talking about, where you can assign different EXS outputs to the instrument groups as you want. I don't have Garage-Band though, so I don't know if this will work with its instrument files. YMMV. However, I haven't been able to get this to work for me (all drums still come through main outputs), although I have confirmed in earlier postings that this is indeed the correct method. Arch Well, the 1st thing to understand (took me a while too,I want to thank Peter Ostry for his last post on the subject)) is that a "Multi Instrument" needs multiple "Aux Out". So, once you've selected your EXS inst as "Multi" (a drum kit I bet!!..),go into the Environment (Audio layer) and create as many Aux Out you need (menu "new"->select Audio Object -> double click it -> go into its parameter window -> select Cha. to Aux "x"). You've now built the sub-mixer that the Multi Inst requested. THEN you can open the EXS's edit window and the big work (pain in the ass!) can start (if somebody knows a short cut!?). You'll have to assign each zone to its aux channel. For this,my tip would be to select (click-shift) first all zones which will go to one aux,(they will appear open in the below window),so you'll just have to check the EXS Output check box and assign the correct aux out . After that,you should be done,you'll just have to set up the new sub-mixer to your taste. Good luck, Alain