One vocal tone, heard as two pitches
In overtone-style throat singing, the singer does not produce a separate high note with a second voice. The vocal folds create a low, buzzy sound containing a fundamental pitch and quieter higher components called harmonics. These harmonics are built into the same sound, like the extra tones that give a musical instrument its distinctive timbre.
The mouth acts like a movable filter
The singer changes the shape of the vocal tract—the spaces in the throat and mouth—by moving the tongue, jaw, and lips. Those changes make certain frequencies resonate more strongly, much as the body of a guitar makes some parts of a plucked string’s sound stand out. When one harmonic is amplified while the others remain quieter, the ear can pick it out as a clear, high note above the low drone.
Small changes in mouth shape can shift which harmonic is emphasized, letting the high melody move while the underlying vocal sound stays comparatively steady. The singer is shaping the sound after it is made, rather than switching between two independent pitches.
Why the effect sounds like two voices
The low fundamental provides a continuous anchor; the emphasized harmonic supplies a brighter, tuneful line. Because both arrive together, the listener hears a drone and melody at once. The striking effect comes from precise control over resonance: a subtle adjustment of the tongue or lips can make a hidden component of one voice suddenly stand out.
