All my beats that were used or people freestyle over have a distinct progressive, "beep. beep. beep.. beep.. beep beep" melody pattern. Don't believe me?
it’s basically an automation, all that mix level automation clip does is turn down the mix level of a reverb making it sound like it’s coming closer to you gradually in fl, just right click the knob you want to automate then click create automation clip. keep in mind some plugins are not native to fl so it might take some extra steps to create an automation clip for those.