 Musical notes are placed by pitch, percussion notes are placed by instrument, and rests and other symbols are placed by convention.The absolute pitch of each line of a non-percussive staff is indicated by the placement of a clef symbol at the appropriate vertical position on the left-hand side of the staff (possibly modified by conventions for specific instruments).For example, the treble clef, also known as the G clef, is placed on the second line (counting upward), fixing that line as the pitch first G above "middle C".