Audibility of dispersion error in room acoustic finite-difference time-domain simulation as a function of simulation distance

Jukka Saarelma, Brian Hamilton, Jonathan Botts, Lauri Savioja

Research output: Contribution to journalArticlepeer-review

Abstract

Finite-difference time-domain (FDTD) simulation has been a popular area of research in room acoustics due to its capability to simulate wave phenomena in a wide bandwidth directly in the time-domain. A downside of the method is that it introduces a direction and frequency dependent error to the simulated sound field due to the non-linear dispersion relation of the discrete system. In this study, the perceptual threshold of the dispersion error is measured in three-dimensional FDTD schemes as a function of simulation distance. Dispersion error is evaluated for three different explicit, non-staggered FDTD schemes using the numerical wavenumber in the direction of the worst-case error of each scheme. It is found that the thresholds for the different schemes do not vary significantly when the phase velocity error level is fixed. The thresholds are found to vary significantly between the different sound samples. The measured threshold for the audibility of dispersion error at the probability level of 82% correct discrimination for three-alternative forced choice is found to be 9.1 m of propagation in a free field, that leads to a maximum group delay error of 1.8 ms at 20 kHz with the chosen phase velocity error level of 2%.
I. INTRODUCTION
Original languageEnglish
Pages (from-to)1822-1832
Number of pages11
JournalThe Journal of the Acoustical Society of America
Volume139
Issue number4
DOIs
Publication statusPublished - Apr 2016

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