title: How to redirect input from one sound card to another?
body: <p>On my PC, I have a total of 2 sound cards.  One of them is built-in to the motherboard and the other one is a USB sound card similar to the one <a href="https://rads.stackoverflow.com/amzn/click/com/B001MSS6CS" rel="nofollow noreferrer" rel="nofollow noreferrer">below</a>.</p>
  
  <p>I have a microphone connected to sound card #1.  When I speak into it, I want the output to be redirected to the speakers connected to sound card #2. And I need to enable this in my app.</p>
  
  <p>The only app I've seen do this is the <a href="http://software.muzychenko.net/eng/vac.htm" rel="nofollow noreferrer">Virtual Audio Cable</a>.  I'd like to replicate the functionality in my app, but I have no idea where to start.  I can start with just 2 sound cards, but eventually I'll need to be redirecting audio traffic with up to 4-8 sound cards.</p>
  
  <p>I am happy to do it in .NET or VB6.</p>
  
  <p><img src="https://i.stack.imgur.com/5oDZ8.jpg" alt="enter image description here"></p>