UE4: How to use the new AudioCapture component to record microphone audio

There are two functions for recording audio:
* Start Recording Output
* Start Recording Submix Output

Steps:
1. Follow this quick start guide to activate the new audio engine, e.g. uncomment AudioDeviceModuleName=AudioMixerXAudio2 in WindowsEditor.ini if you're developing on Windows

2. In your blueprint, add the AudioCapture component

3. Use "Start Recording Output" to record the master output of the game. Otherwise, use "Start Recording Submix Output" to capture a particular sound source (see note #2 below).

4. If you don't specify an output path, it saves the .wav file in Saved\BouncedWavFiles


Note:
* UE4 will crash if no audio input device is connected. Probably should use the "Enumerate Audio Capture Devices" function to check for available devices before recording.

* Setting up a Submix Destination on your Sound Source

Unless otherwise set or specified, all Sound Sources output to the Master Submix (not visible on graph) by default. However, it will sometimes be desirable to have your sound source output into a different Submix.

1. Access the details panel for your sound source
2. Locate the Effects submenu
3. Locate the entry called Sound Submix
   1. If this says “None,” then the sound defaults output to the Master Submix
   2. Here you can enter an alternate Submix
   3. Note the separate Default Master Reverb Send amount if you wish to simply send the source to the Master Reverb

Ref:
Confused about new Audio Capture Component usage in 4.19 - Unreal Engine Forums
New Audio Engine: Early Access Quick-Start Guide - Unreal Engine Forums