Double bass
Double bass symphony parts sometimes indicate that the performer should play harmonics (also called flageolet tones), in which the bassist lightly touches the string–without pressing it onto the fingerboard in the usual fashion–in the location of a note and then plucks or bows the note. Bowed harmonics are used in contemporary music for their "glassy" sound. Both natural harmonics and artificial harmonics, where the thumb stops the note and the octave or other harmonic is activated by lightly touching the string at the relative node point, extend the instrument's range considerably. Natural and artificial harmonics are used in plenty of virtuoso concertos for the double bass.