The Superstringtrio (Rollin Rachele and Mark van Tongeren) performs one of hundreds of Permutations from the Cycle 0... ('Zero-points'), using overtone singing techniques. Often described as a technique of singing where 'a voice produces two tones', you can hear in this piece that two voices each have their own fundamental (ground tone), their own overtones (though it is probably hard to say which belongs to which for most listeners), but also other shades of resonance and psycho-acoustic effects.
The Cycle 0... was conceived by Mark van Tongeren in 2007 in order to systematically explore the dazzling number of possible permutations (or natural harmonies) when two skilled overtone singers consciously sing specific numbers from the harmonic series. The Cycle begins with five Permutationes (permutations indeed), from 0.32 down to 0.28, each with many possible constellations of fundamentals (the lowest and 'normal' tone of the voice) and harmonics (the natural, higher resonances that are present in the human voice when speaking or singing).
This particular piece was part of the performances that took place in Amsterdam, the week when Mark van Tongeren defended his PhD thesis 'Thresholds of the Audible. About the Polyphony of the Body' at the Academy of Creative and Performing Arts, Leiden University, March 2013.
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March 12, 2013
Daphne van Tongeren
Frerik de Jonge, Kleinman Audio
The Academy of Creative and Performing Arts of Leiden University
Dr. Frans de Ruiter, Tim Soekkha