Archontis Politis, 2015

Department of Signal Processing and Acoustics, Aalto University, Finland

archontis.politis@aalto.fi

This Matlab/Octave library was developed during my doctoral research in the [Communication Acoustics Research Group] (http://spa.aalto.fi/en/research/research_groups/communication_acoustics/), Aalto University, Finland. If you would like to reference the code, you can refer to my dissertation published here:

Archontis Politis, Microphone array processing for parametric spatial audio techniques, 2016
Doctoral Dissertation, Department of Signal Processing and Acoustics, Aalto University, Finland

This is a collection of MATLAB routines for simulation of array responses of

a) directional sensors and,

b) sensors mounted on, or at a distance from, a rigid spherical/cylindrical scatterer.

The computation of their frequency and impulse responses is based on the theoretical expansion of a scalar incident plane wave field to a series of wavenumber-dependent Bessel-family functions and direction-dependent Fourier or Legendre functions.

A function for arbitrary open arrays of directional microphones is included not based on the expansion but directly on the steering vector formula of inter-sensor delays and sensor gains for directional patterns (e.g. arrays of cardioid microphones).

Most of the functionality of the library is displayed at [http://research.spa.aalto.fi/projects/arraysim-lib/arraysim.html], or in the included script TEST_ARRAY_SIMULATOR.m

For more information on the expansions, you can have a look on

Earl G. Williams, "Fourier Acoustics: Sound Radiation and Nearfield 
Acoustical Holography", Academic Press, 1999

Heinz Teutsch, "Modal Array Signal Processing: Principles and 
Applications of Acoustic Wavefield Decomposition", Springer, 2007

and for example on [http://en.wikipedia.org/wiki/Plane_wave_expansion] and [http://en.wikipedia.org/wiki/Jacobi-Anger_expansion]

For any questions, comments, corrections, or general feedback, please contact archontis.politis@aalto.fi

For more details on using functions, check their help output in Matlab.

• sph_besselj.m : Various spherical Bessel-family functions and their

• sph_bessely.m : derivatives, for the computation of the radial

• sph_function.m : terms of the expansions (modal weights)

• sph_hankel1.m

• sph_hankel2.m

• dbesselj.m

• dbessely.m

• dhankel1.m

• dhankel2.m

• dsph_besselj.m

• dsph_bessely.m

• dsph_function.m

• dsph_hankel1.m

• dsph_hankel2.m

• simulateCylArray.m : Simulate cylindrical open arrays or arrays of sensors mounted on a rigid cylinder

• simulateSphArray.m : Simulate spherical open arrays or arrays of sensors mounted on a rigid sphere

• cylModalCoeffs.m : Compute the radial (modal) weights for a cylindrical scatterer

• sphModalCoeffs.m : Compute the radial (modal) weights for a spherical scatterer

• sphericalScatterer.m : Compute the response for a measurement point at an arbitrary distance from a rigid spherical scatterer

• cylindricalScatterer.m : Compute the response for a measurement point at an arbitrary distance from a rigid cylindrical scatterer

• getArrayResponse.m' : Simulate open arrays of arbitrary directional microphones with axisymmetric responses