Creating a music visualizer is done using different ways. You can use an application which has pre-built effects and animations which work when the music is playing or use an advanced application (Eg: Adobe After Effects) which requires a little more knowledge because of the action-scripting that needs additional coding.
One simple tool to get you started is called WhiteCap and it has motion and render effects according to what is playing. You can customize the settings to look just how you please.
