Stoner metal is typically slow-to-mid tempo, low-tuned, and bass-heavy. It combines elements of psychedelic rock, blues-rock and doom metal, often with melodic vocals and ‘retro’ production. The genre emerged during the early 1990s and was pioneered foremost by the Californian bands Kyuss and Sleep. Other prominent stoner metal bands include Acid King, Electric Wizard, and Sons of Otis.