Double bass
Bass clef is used for the cello, double bass and bass guitar, bassoon and contrabassoon, trombone, tuba, and timpani. It is used for baritone horn or euphonium when their parts are written at concert pitch, and sometimes for the lowest notes of the horn. Baritone and bass voices also use bass clef, and the tenor voice is notated in bass clef if the tenor and bass are written on the same stave. Bass clef is the bottom clef in the grand stave for harp and keyboard instruments. Double bass, bass guitar, contrabassoon, and tuba sound an octave lower than the written pitch; some scores show an "8" beneath the clef for these instruments to differentiate from instruments that sound at the actual written pitch. (see "Octave clefs" below).