Trap music is a music genre that originated in the early 1990s in the Southern United States. It is a sub-genre of hip-hop music. It is typified by its aggressive lyrical content and sound, where the instrumentals are propelled by 808 kick drums or heavy extended sub-bass lines, double-time, triple-time and other faster time division hi-hats, layered synthesizers, and "cinematic" strings. Trap music is defined by its ominous, bleak, gritty and belligerent lyrical content which varies widely according to every artist. Typical lyrical themes portrayed include observations of hardship in the "trap", street life, poverty, violence and harsh experiences in urban surroundings. Trap music incorporates an extensive use of multi-layered hard-lined and melodic synthesizers; crisp, grimy and rhythmic snares; deep 808 sub-bass kick drums or heavy sub-bass lines; double-time, triple-time and similarly divided hi-hats; and a cinematic and symphonic utilization of string, brass and keyboard instruments creating an overall dark, harsh, grim and bleak atmosphere for the listener. These primary characteristics would go on to be the signature sound of trap music originating from producer Shawty Redd. The tempo of a typical trap beat is around 140 BPM.