Distortion synthesisis a group ofsound synthesistechniques which modify existing sounds to produce more complex sounds (ortimbres), usually by usingnon-linearcircuitsor mathematics.[1]
While some synthesis methods achieve sonic complexity by using manyoscillators,distortionmethods create afrequency spectrumwhich has many more components than oscillators.
Some distortion techniques are:FM synthesis,[2]waveshaping synthesis,[3][4]and discrete summation formulas.[5]
FM synthesis
editFrequency modulation synthesisdistorts the carrierfrequencyof an oscillator bymodulatingit with another signal. The distortion can be controlled by means of a modulation index.[6]
The method known asphase distortion synthesisis similar to FM.
Waveshaping synthesis
editWaveshapingsynthesis changes an original waveform by responding to itsamplitudein a non-linear fashion.[7][8]It can generate a bandwidth-limited spectrum, and can be continuously controlled with an index.
Discrete summation formulas
editDSF synthesis refers toalgorithmicsynthesis methods which use mathematical formulas to sum, or add together, many numbers to achieve a desired wave shape.[9]This powerful method allows, for example, synthesizing a 3-formant voice in a manner similar to FM voice synthesis.[10]DSF allows the synthesis ofharmonicandinharmonic,band-limitedor unlimited spectra, and can be controlled by an index. As Roads points out, by reducing digital synthesis of complex spectra to a few parameters, DSF can be much more economical.[11]
Notable users
editJean-Claude Rissetwas one notable pioneer in the adoption of distortion methods.
References
edit- ^Nb. Some authors refer to these techniques as 'modulation synthesis'; e.g. Chapter 6 ofRoads, Curtis (1996).The computer music tutorial.MIT Press.
- ^Dodge 1997, pp.115-138
- ^Roads, Curtis (June 1979). "A Tutorial on Non-Linear Distortion or Waveshaping Synthesis".Computer Music Journal.3(2). MIT Press: 29–34.doi:10.2307/3680281.JSTOR3680281.
- ^Dodge 1997, pp.139-157
- ^Dodge 1997, pp.158-168
- ^J. Chowning (1973). "The Synthesis of Complex Audio Spectra by Means of Frequency Modulation".Journal of the Audio Engineering Society.21(7).
- ^Arfib, D. 1979. "Digital synthesis of complex spectra by means of multiplication of non-linear distorted sine waves."Journal of the Audio Engineering Society27: 10.
- ^Marc Le Brun. "Digital Waveshaping Synthesis" inJournal of the Audio Engineering Society,27(4), 1979, p250-266.
- ^Moorer, J. A. (November 1976). "The Synthesis of Complex Audio Spectra by Means of Discrete Summation Formulae".Journal of the Audio Engineering Society,27(4), pp.717-727.
- ^T Stilson; J Smith (1996). "Alias-free digital synthesis of classic analog waveforms".Proc. Int. Comp. Music Conf. (ICMC'96 Hong Kong):332–335.CiteSeerX10.1.1.60.4437.
- ^C. Roads 1996, p.260-61.
- Dodge, Charles; Thomas A. Jerse (1997). "5. Synthesis Using Distortion Techniques".Computer Music.New York: Schirmer Books. pp.115–168.ISBN0-02-864682-7.
- Chowning, John; Bristow, David (1986).FM Theory & Applications - By Musicians For Musicians.Tokyo: Yamaha.ISBN4-636-17482-8.
External links
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