An electric guitar is a type of guitar that uses pickups to convert the vibration of its steel-cored strings into an electrical current, which is made louder with an instrument amplifier and a speaker. The signal that comes from the guitar is sometimes electronically tainted with guitar effects such as reverb or distortion. While most electric guitars have six strings, seven-string instruments are used by some jazz guitarists and metal guitarists and 12-string electric guitars (with six pairs of strings, four of which are tuned in octaves) are used in genres such as jangle pop and rock.