Only a few singers are able to use to whistle voice, normally to produce extremely high pitches at the upper limit of their range. The laryngeal mechanism of the whistle voice is not completely understood. Stroboscopy shows only a horizontal vibration, the entire length of the vocal cords vibrating. The vocal cords are stretched to their maximal length. The spectral analysis of the whistle voice shows that the first two partials are much more pronounced than the higher ones. The 3D-PAN of the modal register is more complex than that of the whistle register.