Joyof60:
Not sure if I'm missing something here, but I'll give it a whirl:
First some assumptions from the information you've provided.
- Mic1 -> OCIn1 -> MixA -> OCOut1/2 -> MonitorSet2
-> MixB -> OCOut3/4 -> MonitorSet2
-> Sonar - Mic2 -> Outboard Effects -> OCIn2 -> MixA -> OCOut1/2 -> MonitorSet1
-> MixB -> OCOut3/4 -> MonitorSet2
-> Sonar - OCIn1 in both MixA and MixB is not muted and at sufficient level to allow signal into each mix
- OCIn2 in both MixA and MixB is not muted and at sufficient level to allow signal into each mix
If the above assumptions are correct, then all you really need to do to keep Mic2's processed signal from going into MonitorSet1 and MonitorSet2 is to mute OCIn2 in both MixA and MixB on the Direct Mixer of the OC's control panel. This will keep Mic2's signal out of both monitor sets while still allowing the signal to be recorded by Sonar.
As I understand it, the controls on the Direct Mixer of the OC's Control Panel is for each mix, not for what gets routed to the OC's high-speed USB audio channels. It's the VS-Preamps that control the signals, and their levels, that get routed into the OC. Whatever signals comes through any of the OC's VS-Preamps get routed to the each of the direct mixers as well as the high-speed USB audio channels. So you can mute one of the inputs on the mixes and still be able to record the signal in Sonar as I've suggested above.
Hope my assumptions are correct and that this helps you out,
Paul