RØDE's RØDECaster Pro II is a great, feature-rich audio interface for use with Ecamm Live. It can add some powerful audio features to your broadcast.
There are two important but easy set-up steps for using RCP 2 (or RCPII) with Ecamm Live:
Pick The Rodecaster Pro II Chat Input
In Ecamm Live, find the Sound Levels window. If you don't see it, pick Sound Levels from the Window menu at the top of the screen.
The first row of the Sound Levels window is your microphone input. Click the popup menu to select the device. You may see more than one option there for the RodeCaster device. Be sure to pick the entry called Rodecaster Pro II Chat.
Turn On Stereo Mode In Ecamm
In the Audio section of Ecamm Live's preferences, pick the checkbox labeled Map Input Channels 1 And 2 To Left and Right Stereo. This will use only channels 1 and 2 from the RodeCaster, and ignore any other input channels.