On the song “Portrait of Tracy,” a performer of this instrument innovated its “octave technique” and heavily used artificial harmonics. Another performer of this instrument wrote an elegy to Lester Young that is named after the hat Young wore. The tracks “Goodbye Pork Pie Hat” and “Fables of Faubus” are in an album by a bandleader who primarily played this instrument (10[1])and is partially titled Ah Um. Famous performers of this instrument include Esperanza Spalding, Ron Carter, and Charles Mingus. (10[1]-5[1])For 10 points, (10[1])name this stringed instrument that makes up a jazz rhythm section with the piano and drums and is pitched lower than a guitar. ■END■ (10[1])