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I. Spatial Acoustics Library for MATLAB (SALM)
II. Dataset of near-distance head-related transfer functions

I. Spatial Acoustics Library for MATLAB (SALM)

The spatial acoustics library for MATLAB (SALM) contains a collection of Matlab functions and scripts for spatial acoustic signal processing and spatial audio processing.

The GitHub repository of this project is available at https://github.com/cesardsalvador/SpatialAcousticsLibraryMATLAB.

If you use any script, function, or dataset available in this repository, please cite SALM as below:

  • C. D. Salvador, “Spatial Acoustics Library for MATLAB (SALM),” GitHub, Feb., 2024.
    DOI: 10.5281/zenodo.10648288


    II. Dataset of near-distance head-related transfer functions

    The head-related transfer functions (HRTFs) are linear filters describing the transmission of sound from a point in space to the eardrums of a listener. They describe the acoustic filtering properties of the listener's external anatomical shapes such as their torso, head, and outer ears. The HRTFs contain spatial information used by the listener to locate the source of a sound and constitute a major tool in spatial sound technology for personal use.

    Obtaining HRTFs for sound sources at reaching distances is important to increase the realism and naturalness when presenting sounds in the peripersonal space. A dataset of near-distance HRTFs is being constructed as part of the JSPS Project “Perceptual Constancy in Spatial Hearing” (JP17K12708).

    Currently, four models of listeners' heads compose the HRTF dataset: two generic models captured by laser scanning and two individual models captured by magnetic resonance imaging. Circular and spherical distributions of point sources around the heads, at distances ranging from 10 cm to 100 cm, spaced 1 cm, are being considered. HRTFs are calculated using the boundary element method (BEM) in the frequency domain. The BEM solver runs on the scalar-parallel supercomputer of the Cyberscience Center, Tohoku University. Results are stored as free-field head-related impulses responses (HRIRs) in the time domain.



    Figure 1. Generic (left) and individual (right) models.




    Figure 2. Left-ear HRTFs at 10 kHz for a spherical distribution of sources at 25 cm from the head center.




    Figure 3. Interaural HRTFs for a distribution of sources along distances at azimuth 100° and elevation 20°.

    Circular and spherical HRIR datasets for one of the individual models (third from left in Fig. 1) are publicly available in the spatially-oriented format for acoustics (SOFA). Accessing the data requires MATLAB or GNU Octave. In addition, it is necessary to install the SOFA Matlab/Octave API version 1.0.2. The datasets can be downloaded from the links in Table 1.

    Table 1. HRIRs and metadata for the third model from left in Fig. 1.
    Source distribution Description SOFA File containing HRIRs and metadata MATLAB Script to read SOFA File
    Circular, equiangular distributions on the horizontal plane. ind01_h_circ_hor_dir360_dist141.sofa read_sofa_circ_hor.m
    Circular, equiangular distributions on the median plane. ind01_h_circ_med_dir360_dist91.sofa read_sofa_circ_med.m
    Spherical, equiangular, vertical-polar distributions. ind01_h_sph_equivert_dir614_dist91.sofa read_sofa_sph_equivert.m
    Spherical, equiangular, interaural-polar distributions. ind01_h_sph_equiint_dir614_dist93.sofa read_sofa_sph_equiint.m
    cart2isph.m
    isph2cart.m
    Spherical, nearly-regular, icosahedral distributions. ind01_h_sph_ico_dir642_dist93.sofa
    ind01_h_sph_ico_dir2562_dist21.sofa     		read_sofa_sph.m
    Spherical, nearly-regular, maximum-determinant distributions. ind01_h_sph_md_dir625_dist93.sofa
    ind01_h_sph_md_dir2500_dist21.sofa
    Reference and citation
  • C. D. Salvador, S. Sakamoto, J. Treviño, and Y. Suzuki, “Dataset of near-distance head-related transfer functions calculated using the boundary element method,” in Proc. Audio Eng. Soc. Int. Conf. Spatial Reproduction —Aesthetics and Science—, Tokyo, Japan, August 2018. [Permalink: http://www.aes.org/e-lib/browse.cfm?elib=19602] [PDF]