David Hykes and the Overtone Choir expand beyond the scope of the traditional tantric Tibetan Buddhist chant, in which the singer holds one steady note and one unmoving harmonic.
They also expand beyond the traditional Mongolian Hoomi singing, in which the singer projects soaring harmonic melodies from the overtone series of the steady fundamental.
The singers create new melodies and chords by simultaneously moving both the harmonic and fundamental notes, sometimes in converging directions, or by holding the high harmonic while varying the fundamental.