All LIVE classes do require a headset with a microphone. Some courses may use video during class. The feedback created by built-in computer mics is disruptive to classes. You will NOT be able to use your computer microphone and audio.
Here is a list of suggested headsets:
Economical: Logitech Stereo Headset
Middle: Pacrate Gaming Headset with Microphone
Ultra: Corsair Headset
Wireless: Wireless Corsair Headset