title: How to record audio from microphone (Line-In) and playback device (speakers Line-Out) to one MP3 file
body: <p>I am trying to record audio from the microphone and speakers to one MP3 file. </p>
  
  <p>How to achieve this in C# with NAudio? </p>
  
  <p>I have already recorded audio from microphone, but I can't figure out how to record from speakers, and then mix to one MP3 file.</p>