On his very solid debut Issa Album, Atlanta's 21 Savage sticks to a storied rap tradition arguably perfected by the South: that of making your music as nightmarish as possible. Admittedly, the album's not as much of a sonic black hole as last year's impeccable Savage Mode with comparatively lighter crossover attempts alleviating the dark aura that pervades 21's work. Nonetheless, the album is unapologetically gangsta, and not just in the words. Though it's not the first to do so, the production on the album uses repetitive strands of melody to illustrate the bleakness and aggression of 21's outlook.
Obviously, instrumental loops are among hip-hop's musical foundations. Thus, when composing an original beat that doesn't use samples, producers will typically find any reasonably memorable 4-bar melody and use that as the basis for the track. Issa Album main beatmaker Metro Boomin utilizes this technique on "Numb," "Bank Account" and others, as he has for years on his beats for Atlanta's finest. A melody that repeats with no change whatsoever is called an ostinato. Guitar and keyboard riffs in rock and pop also count as ostinatos, but they're typically more inviting. In rap, especially Southern rap, the repetitive, ringing ostinato is an alarum that signifies fights, mayhem, and death.
One can trace the uses of ostinato in the South back to Three 6 Mafia's horrorcore-leaning early music as displayed on 1995's seminal Mystic Stylez and the work of other Hypnotize Minds affiliates. At the time, the dominant styles of LA and NYC rap were sample-based, which meant that the synth-based beats of the South stood out. Crunk further developed this, with the timeless "Knuck If You Buck" possibly the greatest example of the tear-the-club-up Dirty South ostinato melody. Possible influences are the classic horror movie scores of Halloween, Suspiria, and The Exorcist, which contain high-pitched ostinatos as their main themes. Many of these themes have been sampled in hip-hop as well, so the link between the worlds of film and rap is pretty apparent. But why are these ostinatos so innately eerie?
The answer is in how our ears expect melodies to resolve. The distance between notes is called an interval, and most of them sound pleasant to us. The two that don't are the tritone and the semitone. Tritones are famous as "the devil in music" and through their omnipresence in heavy metal but semitones don't get as much shine, despite being more dissonant when played together (mash two piano keys that sit next to each other at the same time and tell me if that sounds nice—it probably doesn't). Utilizing notes that are semitones apart—as heard in "Knuck if You Buck" and 21's "Bank Account"— is part of what's called chromaticism, which is essentially considered "wrong" when adhering to the "normal" diatonic scale. These tones have been associated with everything from weeping to the "other," so the message is clear: these melodies are sorrow.
The ostinatos of trap buck trends of conventional, "nice" harmony (pun intended) and unbalance the listener, letting them know that they are not in safe waters. Combined with their repetitive nature, they're a needling pinprick in the ear of the listener, meant to agitate and irritate. Granted, many producers probably don't think this hard: "Crank That" uses a chromatic note in its signature MIDI steel drum hook but Soulja Boy was definitely just hitting whatever felt right on the keyboard. Still, that this is what the ears of Atlanta producers gravitate to says a lot about they consider to be effective compositions. Even fictional Southern rappers have spit on chromatic compositions, after all. 21 Savage is part of a long history of making scary music to party to, of turning horrific real-life experiences into resonant hits. He does that with the help of the subtly disharmonious backdrops, upsetting the natural order but nonetheless inciting the need to get up and wild out.
Phil is a Noisey staff writer. He's on Twitter.