Many tracks, especially within the genres of house and trance, have a habit of arranging a track for a DJ. The producer purposely places a section at the start, beginning with a simple kick drum and building up adding a new sound at the end of every 4, 8 or 16 bars finally adding the bass at some point. Then whilst getting towards the end of the track, the parts are faded out, most of the time as a mirrored version of the intro. This was started as a way to make life easier for the DJ by allowing long and smooth transitions between tracks when the are mixed together. I have some thoughts about this that I want to share.