Nestor Kornblum sings the melody of Amazing Grace using only the overtones (harmonics) in his voice. There are NO musical instruments or electronic effects involved. Nestor is co-director and co-founder of the International Association of Sound Therapy, and also of Harmonics Inc. Nestor has a an OVERTONE GUIDE BOOK +CD available on http://www.soundhealing.net Nestor Kornblum canta la melodía de esta canción tradicional empleando solo los armónicos de su voz NO HAY instrumentos ni efectos o manipulaciones! Su Libro-Guía para aprender a cantar armónicos se encuentra en la tioenda de su página http://www.sonidosquesanan.net.