I originally wrote this article in September of last year - before I saw the movie, "Now You See Me." I'm updating it because we just watched that excellent movie, and the effect I describe below for using ducking in electronic music can be clearly heard in the soundtrack at the end of the movie, during the credits. On the soundtrack album, the song is track number 8, "Now You See Me - Robert DeLong Remix." It's an electronic variation of the "Now You See Me" theme composed by Brian Tyler. Take a listen at the iTunes store here.
Ducking in audio recording is a really useful effect for any number of things. The basic idea is that when the audio on one track (you need multi-track recording software for this) gets louder, the audio on another track (or even all the other tracks) get less loud. It's like one track pushes the other track(s) down and out of the way. Or put another way - the other track(s) "duck" out of the way of of the controlling track.
I wrote about how to do this using Reaper multi-track software in my article What is Ducking In Audio Recording? The object is most commonly to allow a single voice to be clearly heard over some background music. So whenever the audio on the vocal track is sounding, the volume on the music track gets correspondingly less loud. When listening to JUST the music track in that case, it sounds a bit weird. But when combined with the vocal track, you don't even notice that the music is getting softer at those points because the voice fills in the void.
The way that one track controls another is by use of something called "side-chaining," which just means that you send some of the output of one track to another track. In ducking, you put a compressor effect on the track that you want to do the ducking - the music track in the above example. But instead of the music controlling the action of the compressor, you bring in the audio from a different track (the vocal track in our example) to feed/control the compressor on the track doing the ducking.
But remember that I said ducking can be used for a lot of different effects? And remember when I said that listening to JUST the track doing the ducking can sound weird, since it is inexplicably lowering and raising its volume at seemingly random times? Well we can use THAT in Electronic Dance Music (EDM).
The idea is to set up a music track with a pad (synthesizer playing a long, sustained sound - a note or chord), and then to cause the the volume of that music to drop almost completely out periodically - typically to the rhythm of the song. So you set up a drum track to be the controlling track, and whenever a drum hit happens, the volume of the music track drops, gving out a sort of pulsing, throbbing sound perfect for EDM. Then just mute the drum track, and you have a very rhythmic and dance-to-able synth pad track.
The following article shows you how to do the EDM ducking thing using Cakewalk's Sonar X2 Producer software. Of course you can do the same thing in Reaper using the same technique I described in the article linked at the top of the page.
Red that article here: http://blog.cakewalk.com/edm-ducking-synth-melodies/