Vector Phaseshaping Synthesis (VPS)

Proc. of the 14th Int. Conference on Digital Audio Effects (DAFx-11), September 19-23, IRCAM, Paris, France, 2011.

1 Aalto University, School of Electrical Engineering, Espoo, Finland
2 National University of Ireland, Maynooth, Ireland


This paper introduces the Vector Phaseshaping (VPS) synthesis technique, which extends the classic Phase Distortion method by providing flexible means to distort the phase of a sinusoidal oscillator. This is achieved by describing the phase distortion function using one or more breakpoint vectors, which are then manipulated in two dimensions to produce waveshape modulation at control and audio rates. The synthesis parameters and their effects are explained, and the spectral description of the method is derived. Certain synthesis parameter combinations result in audible aliasing, which can be reduced with a novel aliasing suppression algorithm described in the paper. The extension is capable of producing a variety of interesting harmonic and inharmonic spectra, including for instance, formant peaks, while the two-dimensional form of the control parameters is expressive and is well suited for interactive applications.


The figures presented in the paper can be reproduced using these python scripts (tested with SciPy v0.7.1).

Sound Examples

The sounds are 32-bit float wavs, sampling rate is 44.1 kHz.
A) control rate modulation
  Sound   Description   Size (MB) 
vps-chord.wav 5 modulation clips: d, v, v and d, lissajous (sinusoidal LFO on v), lissajous (pulse LFO on v) 2.15
vps-d.wav d modulated, constant v = 0.5 1.76
vps-v.wav v modulated 0..5, constant d = 0.5 3.23
vps-v-aa.wav v modulated 0..5 (alias suppression using two-oscillator crossfading), constant d = 0.5 3.07
vps-resonant.wav varying d and v manually with a 2D controller 1.63
vps-resonant-aa.wav varying d and v manually with a 2D controller (alias suppression using two-oscillator crossfading) 2.55
vps-lissajous1.wav Lissajous modulation #1 1.84
vps-lissajous2.wav Lissajous modulation #2 2.15
B) audio rate modulation
  Sound   Description   Size (MB) 
vps-lissajous1-ar.wav Lissajous modulation #1 1.83
vps-lissajous2-ar.wav Lissajous modulation #2 1.55

All sound examples (18.4 MB):


Please send your comments and remarks to the first author: firstname.lastname[-at-]

Page last modified Sep-21-2011.