OVERTONE SINGING - A Western Therapeutic Perspective and Oriental example
Overtone singing is an ancient technique that enables a singer to produce 2 or more sounds simultaneously with his or her voice. Overtone singing as a technique and cultural or spiritual musical artform, developed in Mongolia , Southern Siberia and Central Asia, in Tibet , and in South Africa . It also is used to a lesser degree in Sardinia , the only ancient form of European overtone singing that is still practiced. Many theories exist that overtone singing once had a ritual and spiritual use in Kabbalistic ceremonies, Masonic lodges, mystery schools and Sufi practices. Overtones, known also as harmonics, were first discovered in the West by Pythagoras some 2 600 years ago. The famous Greek philosopher and mathematician was also a musician, and together with his students spent years studying sound and vibration. He found, after studying the monochord, a single stringed instrument, that all sounds were composed of multiple vibrations or frequencies, not just one, as our ears generally perceive. In much the same way that white light is made up of a wide spectrum of colours, which become visible when the light is refracted through a prism, sound too can be refracted so that its constituent parts can be perceived. Just as the rainbow is made up of the colours that the human eye sees as white light, overtones (harmonics) are the colours of sound. These overtones, which usually go unnoticed, are actually vitally important for all human beings, and allow us to differentiate between one sound and another. It is the richness of the overtones in certain parts of the infinite spectrum of sound which help us to tell the difference between one musical instrument and another, even when they both play the same musical note. Our brain can tell immediately whether a certain note has been played by a flute, a guitar or a piano. If the overtones are filtered out, we become unable to distinguish between these instruments. The human voice is the musical instrument richest in overtones, due to our ability to make the tiniest of adjustments at will, thus fine-tuning the voice beyond the capacity of most musical instruments.
Source: http://www.globalsoundhealing.net/es/node/18 Overtone Singing, A Western Therapeutic Perspective