Acid

This is the standard that most of producers work on. In these type of projects the base is original from the producer — chords, melodies, leads, etc — but it contains additional melodic elements that complement the track and come from royalty-free sample packs. They are usually vocal chops, real instrument chords or textures, wobbles basses, glitch effects, etc. In a project file of this category you will find MIDI files created by the producer, but also melodic loops