In the Perfect World, everything would be digital and the only noise introduced into mix would be intentional. Of course, this isn't a perfect world (at least not yet), and so unwanted noise does exist - but you can do something about it!
AnalogX Gate is the DirectX version of probably one of the oldest and most commonly used audio effects out there - the gate. A gate simply ensures that until the volume of an input passes a certain Threshold, no signal is sent through; then once a signal comes through the gate remains open until the signal drops below another threshold.
Of course, Gate requires an application that supports DirectX Audio plugins (like the Paris or Wavelab), and works with either the realtime or non-realtime applications as well. Gate supports mono or stereo sound streams, as well as 16bit and 32bit data types.