If you know anything about graphic EQs and listen to a lot of music on your phone you must have this app! Its amazing! Im a recording engineer so I like to think I have a pretty good ear for audio, and the things this app lets me do and add to music recorded yesterday or in the 50s is phenomenal! Just make sure you know what and how a graphic EQ is and you will spend hours fine tuning previously recorded music, to sound better through what ever device! Get it now if your in the know!