Rap music is music. However, It's not in the traditional sense of how we understand music. The vocals are filled with slangs that gangs used since the 70s and a lot of the instrumentations are replaced with "Street Sounds" instead of traditional instruments. Music is defined as any combination of sounds that is pleasing to the ear, so while one person may find it as "noise" another person can find it pleasing to the ear and so call "vibe" with it as how I think the kids would say it these days.
Comment