So you want to make a Skype call or Beam into a remote location and you're using your computer to generate your voice. You try it out and you find it doesn't work very well.
Teleconferencing software has a feature called acoustic echo cancellation or AEC for short which is used to remove echo and feedback from the audio channel. It works by automatically subtracting the audio coming out of the computer speakers from what it picks up with the microphone -- removing your synthesized voice in the process!
So now you find a workaround, adding a second microphone to your computer to defeat the echo canceller. This works to a point, but it degrades the quality of the call and it's an additional piece of hardware you need to buy & manage that you don't otherwise use.
It turns out there's a better way -- there's a little known feature in Windows called 'Stereo Mix' that lets you use the output of your soundcard as a 'virtual microphone' on some Windows computers, like the Surface Pro 3. It starts from the Sound control panel...
Sound Control Panel
Right Click to Show Disabled Devices
Disabled Stereo Mix device (not present on all sound cards)
Right Click to Enable
Change the microphone in your teleconferencing app to Stereo Mix
There you go, quality sound, no additional hardware needed, and even better no background noise from the dog or the kid or...