I've had a AT2020 USB mic for a while but I recently bought a Scarlett 2i2 and a MXL 990. Is it possible for me to record both microphones in Reaper? If so how? I know it'd be ideal to just get another xlr microphone and I will eventually, but for now I'd like to utilize what I have if at all possible.
You can do this, I think, using Mac OS X's aggregate audio devices. Some advice on how these work and how you can set one up is found at the following links:
The Reaper Blog says this is 'ok overall but not reliable enough for professional studio work' due to some latency and timing issues. Fair enough.
If you're on Windows, ASIO4all might do it.
You can select ASIO4all as your audio device within Reaper, and then select multiple devices in ASIO4all's configuration, which will then look like a single device to Reaper. You'll then need to close and reopen Reaper's audio device configuration before you can choose which inputs / outputs Reaper will use.
I haven't tested this, so it's possible you might run into sync problems or something - worth a try though...