Synthesis and Control of Hundreds of Sinusoidal Partials on a Desktop Computer without Custom Hardware

cote interne IRCAM: Rodet92bNational audienceThe idea of synthesizing sounds by summing sinusoidal oscillations [Helmholtz1863] has intrigued generations of musical instrument builders. ThaddeusCahill's electromechanical implementations [Nicholl 93] illustrate graphically thebasic challenge faced by these engineers--the creation of a large number ofoscillators with accurate frequency control. (...)One hundred years after Cahill's work, despite rapid gains in computationalaccuracy and performance, the state of the art in affordable single chip real-timesolutions to the problem of additive synthesis offers only 32 oscillators. Sincehundreds of sinusoids are required for a single low pitched note of the piano, forexample, current single chip solutions fall short by a factor of at least 20. This paper describes a new technique for additive synthesis, FFT-1, that offers aperformance improvement of this order. This technique also provides an efficientmethod for adding colored noise to sinusoidal partials, which is needed tosuccessfully synthesize speech and the Japanese Shakuhachi flute, for example.Before describing the details of the FFT-1 method, additive synthesis will becompared to the popular synthesis methods: frequency modulation[Chowning 73] and digital sampling