R&B originated after the demise of disco in the 1980s and is now often referred to as urban contemporary. Hip hop emerged in the South Bronx and first involved DJs creating beats by looping breaks on turntables, later accompanied by rap in 16 bar measures and beat boxing. Dubstep originated in South London and has tight bass lines and drum patterns at a tempo of 138-142 BPM, often with a snare on the third beat.