Nx Witness allows for audio recording from devices that are audio-enabled and have a microphone connected.
Open the device context menu and go to the General tab, then check the Enable Audio checkbox and click Apply or OK to accept the change.
It may also be useful to use the device's web page for further controls. See "Configuring Proprietary Device Parameters" for details.
You can configure audio for multiple devices at once. See "Sharing Parameters on Multiple Devices".