The bass guitar gives most metal bands their distinctive low-pitched foundation. It commonly reinforces the rhythm guitar and drums while adding its own melodic, rhythmic, or textural lines.
A standard electric bass usually has four strings tuned E–A–D–G from lowest to highest, although five- and six-string instruments are common in metal. Lower tunings and extended-range basses help performers match the deep sound of down-tuned guitars.
The bass should not be confused with the electric guitar, which generally plays in a higher register and carries many metal riffs and solos. In bands such as Iron Maiden, Metallica, and Tool, the bass can be especially prominent in the overall arrangement.