Dynamical systems for audio Synthesis: Embracing nonlinearities and delay-free loops

7Citations
Citations of this article
7Readers
Mendeley users who have this article in their library.

Abstract

Many systems featuring nonlinearities and delay-free loops are of interest in digital audio, particularly in virtual analog and physical modeling applications. Many of these systems can be posed as systems of implicitly related ordinary differential equations. Provided each equation in the network is itself an explicit one, straightforward numerical solvers may be employed to compute the output of such systems without resorting to linearization or matrix inversions for every parameter change. This is a cheap and effective means for synthesizing delay-free, nonlinear systems without resorting to large lookup tables, iterative methods, or the insertion of fictitious delay and is therefor suitable for real-time applications. Several examples are shown to illustrate the efficacy of this approach.

Figures

  • Figure 2. Block diagrams showing the signal flow for reciprocal sync. Using dyamical oscillators. (a) Using lookup oscillators; (b) Using dyamical oscillators.
  • Figure 3. The output of (a) two digital lookup oscillators in a tight sync loop and (b) another pair given Equations (16) and (17) fed to the fourth order Runge-Kutta (RK4) method for solution. (a) 950 Hz and 900 Hz digital lookup oscillators in reciprocal sync. θ = 0.9; (b) The same parameters but using the dynamical model in Equations (16) and (17).
  • Figure 4. Signal flow diagram for a reciprocal frequency modulation (FM) scheme without delay.
  • Figure 5. Spectrograms of (a) reciprocal frequency modulation using lookup oscillators of frequencies 800 Hz and 777 Hz in the top and 800 Hz and 600 Hz in the bottom; In (b) the same network with the same frequencies, but using the ODE (ordinary differential equation) + RK4 implementation. In all four plots the modulation index of the 800 Hz oscillator is held fixed while the other modulation index is swept upwards.
  • Figure 6. Sweeping the modulation index in feedback FM.
  • Figure 7. The bowed oscillator model given here (solved with RK4) and that given in [21]. In both implementations, oscillator frequency f = 200, Fb = 500, vb = .2 and a = 100. (a) The system given in Equation (25) solved using RK4; (b) Using Newton-Raphson and Backward Euler to solve Equation (23).
  • Figure 8. RK4 solving Equations (25) using (a) the continuous friction model in Equation (24) and (b) Equation (26). (a) Differentiable friction model; (b) Discontinuous friction model.
  • Figure 9. Plots illustrating the character of the ODE + RK4 implementation of the Moog filter. (a) Shown is the difference between target frequency and highest peak in the spectrum as well as amplitude for the ODE + RK4 Moog filter; (b) Sweeping fc across a noise stimulated Moog filter for various values of r (sampling rate is 48 kHz).

References Powered by Scopus

Numerical Sound Synthesis: Finite Difference Schemes and Simulation in Musical Acoustics

284Citations
N/AReaders
Get full text

Elimination of delay-free loops in discrete-time models of nonlinear acoustic systems

96Citations
N/AReaders
Get full text

Automated physical modeling of nonlinear audio circuits for real-time audio effectspart I: Theoretical development

94Citations
N/AReaders
Get full text

Cited by Powered by Scopus

Antiderivative antialiasing for memoryless nonlinearities

31Citations
N/AReaders
Get full text

Iterative Phase Functions on the Circle and Their Projections: Connecting Circle Maps, Waveshaping, and Phase Modulation

3Citations
N/AReaders
Get full text

Estimating the first and second derivatives of discrete audio data

0Citations
N/AReaders
Get full text

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Cite

CITATION STYLE

APA

Medine, D. (2016). Dynamical systems for audio Synthesis: Embracing nonlinearities and delay-free loops. Applied Sciences, 6(5). https://doi.org/10.3390/app6050134

Readers over time

‘16‘17‘18‘20‘2100.511.52

Readers' Seniority

Tooltip

PhD / Post grad / Masters / Doc 4

67%

Professor / Associate Prof. 1

17%

Researcher 1

17%

Readers' Discipline

Tooltip

Arts and Humanities 3

50%

Computer Science 1

17%

Chemistry 1

17%

Engineering 1

17%

Save time finding and organizing research with Mendeley

Sign up for free
0