About Mesh2HRTF

Head-related transfer functions (HRTFs) describe the listener-specific directional filtering of the incoming sound at the entrance of the ear-canal. HRTFs are caused by a scattering process, thus, they can be numerically calculated by simulating the sound-field scattered by the human head and ear. Various simulation methods for the numerical calculation of HRTFs were investigated, with a particular research effort focused on the boundary-element method (BEM). In most of these studies, researchers either had to use commercial software or to implement the BEM by themselves.

In 2012, to simplify the process of HRTF calculation, development of Mesh2HRTF was initiated at the Acoustics Research Institute of the Austrian Academy of Sciences and programmed by Harald Ziegelwanger using the numerical core basis from Wolfgang Kreuzer under the lead of Piotr Majdak.

Nowadays, Mesh2HRTF is a collaborative work of the Acoustics Research Institute of the Austrian Academy of Sciences (Austria) and the Audio Communication Group of the Technical University of Berlin (Germany).

Mesh2HRTF is an open-source project providing an easy-to-use software package targeting researchers in the field of binaural audio. Mesh2HRTF reads geometrical data, calculates the corresponding sound field, and outputs HRTFs as a SOFA file. To support multiple computer platforms, the concept of Mesh2HRTF focuses on a command-line numerical core called NumCalc implementing the 3D Burton-Miller collocation BEM coupled with the multi-level fast multipole method (ML-FMM). Other parts of Mesh2HRT provide add-ons for Blender for geometry preprocessing and tools for Python and Matlab for post-processing and visualization purposes.

Mesh2HRTF 0.x was initially released in 2015 under the GPL3 license. It was used for the numerical calculation of HRTFs in many studies. The current version of Mesh2HRTF, Mesh2HRTF 1.x was released in February 2023 and is available under the EUPL v1.2-or-later. See the License section when using Mesh2HRTF.

Simulate

the sound field

By coupling the BEM with the multi-level fast multipole method, Mesh2HRTF is able to simulate the sound field and to calculate HRTFs for the whole audible frequency-range, i.e., for head and pinnae meshes with more than 100 000 triangular elements.

SOFA

Spatially oriented format for acoustics

Mesh2HRTF saves HRTFs and HRIRs as SOFA files. SOFA is the official standard AES69 of the Audio Engineering Society for storing HRTFs.

References

Mesh2HRTF was presented for the first time at the 22nd ICSV in Florence:

• Ziegelwanger, H., and Kreuzer, W., Majdak, P. (2015). "Mesh2HRTF: An open-source software package for the numerical calculation of head-related transfer functions," in Proceedings of the 22nd International Congress on Sound and Vibration, Florence, Italy.

Since then, Mesh2HRTF was used in many publications:

• Ziegelwanger, H., Majdak, P., and Kreuzer, W. (2015). “Numerical calculation of listener-specific head-related transfer functions and sound localization: Microphone model and geometry discretization,” The Journal of the Acoustical Society of America, 138, 208–222. DOI:10.1121/1.4922518.
• Ziegelwanger, H., and Majdak, P. (2014). “Modeling the direction-continuous time-of-arrival in head-related transfer functions,” The Journal of the Acoustical Society of America, 135, 1278–1293. DOI:10.1121/1.4863196.
• Ziegelwanger, H., Kreuzer, W., and Majdak, P. (2016). “A priori mesh grading for the numerical calculation of the head-related transfer functions,” Applied Acoustics 114, 99–110. DOI:10.1016/j.apacoust.2016.07.005.
• ... a more complete list of publications using Mesh2HRTF 0.x.

The reference to NumCalc:

• Kreuzer, W., Pollack, K., Brinkmann, F., and Majdak, P. (2024). “NumCalc: An open-source BEM code for solving acoustic scattering problems,” Engineering Analysis with Boundary Elements, 161, 157-178. DOI:10.1016/j.enganabound.2024.01.008. Bibtex.

The reference to Mesh2HRTF 1.x:

• Brinkmann, F., Kreuzer, W., Thomsen, J., Dombrovskis, S., Pollack, K., Weinzierl, S., Majdak, P. (2023). "Recent Advances in an Open Software for Numerical HRTF Calculation," The Journal of the Audio Engineering Society, 71: 502-514. DOI:10.17743/jaes.2022.0078. Bibtex.