XSplit Broadcaster allows you to add multiple audio sources from your webcam mic, audio interface, headset mics, and more.
Go to Add Source > Audio Device
Right-click on the Audio source to bring up the properties window where additional options are available.
This is locked by default, and should show the name of the Audio input device under this properties window.
Here you can select between Stream Only (which routes the audio input directly to your stream and not through your system sound), or System Sound (which causes the audio to be heard from your system sound output device.
Use this setting to correct audio/video sync issues between your camera sources and this particular audio device.
Allows you to select which audio source will be used and configured under the already-added source.
Use this option (when available) for additional audio input configuration settings for your camera source.
Shows additional audio input properties specific to your camera source.