USB Webcams without built-in microphone: If your webcam does not have a built-in microphone then make sure that your external microphone is properly working and connected to your audio card, try and change your audio settings at http://mycast.orb.com > Open Application > Control Panel > TV/Webcams > Devices > expand the plus sign in front of your Webcam, try a different Audio Input and try again

USB Webcam models with built-in microphone: You may have selected an incorrect audio input at http://mycast.orb.com > Open Application > Control Panel > TV/Webcams > Devices > expand the plus sign in front of your Webcam, try a different Audio Input and try again.