In this video I explain what is sidechain compression, otherwise known as ducking.  I discuss when to use the ducking effect in mixing and why, how to set it up in pro tools or logic, and explain which settings to use in your compressor.  In this example I use Waves C1 plugin, and have my kick and snare drums trigger the compressor to duck my keyboard pad.  Sidechain compression is a good way to add impact to your kick and snare drums.