Local Time-Domain Spherical Harmonic Spatial Encoding for Wave-Based Acoustic Simulation

Stefan Bilbao*, Archontis Politis, Brian Hamilton

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

12 Citations (Scopus)
80 Downloads (Pure)


Volumetric time-domain simulation methods, such as the finite difference time domain method, allow for a fine-grained representation of the dynamics of the acoustic field. A key feature of such methods is complete access to the computed field, normally represented over a Cartesian grid. Simple solutions to the problem of extracting spatially encoded signals, necessary in virtual acoustics applications, result. In this letter, a simple time-domain representation of spatially encoded spherical harmonic signals is written directly in terms of spatial derivatives of the acoustic field at the receiver location. In a discrete setting, encoded signals may be obtained, at very low computational cost and latency, using local approximations with minimal number of grid points, and avoiding large convolutions and frequency-domain block processing of previous approaches. Numerical results illustrating receiver directivity and computed time-domain responses are presented, as well as numerical solution drift associated with repeated time integration.

Original languageEnglish
Article number8656507
Pages (from-to)617-621
Number of pages5
JournalIEEE Signal Processing Letters
Issue number4
Publication statusPublished - 1 Apr 2019
MoE publication typeA1 Journal article-refereed


  • ambisonics
  • Finite difference time domain (FDTD)
  • microphone array
  • room acoustics
  • spatial audio
  • spherical harmonics


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