A simple multiband approach for solving frequency dependent problems in numerical time domain methods

Sheaffer, J; Fazenda, BM; Murphy, DT; Angus, JAS

Abstract

With the rapid growth of computational power and recent advances in GP-GPU technology,
numerical time domain methods are becoming increasingly popular for room acoustics applications
due to their accuracy, simplicity and ease of implementation. However, in order to model realistic
spaces one should consider boundary conditions and source directivity functions as empirically
measured frequency dependent quantities. Previously suggested methods rely on performing time
domain convolution or employing recursive filters at the boundaries of the domain. Although shown
to be highly accurate, these formulations normally involve complex implementations which not only
reduce the attractiveness of using such methods, but may also result in computationally expensive
algorithms. In this paper we examine a straightforward approach for solving such frequency
dependent problems at the expense of being able to run a single broadband simulation. Using the
finite difference time domain (FDTD) method, a number of band-limited frequency independent
simulations are initiated in intervals depending on the availability of empirical impedance and
directivity data and the desired spectral resolution. Generated impulse responses are filtered
according to their respective frequency bandwidths and summed to produce a single frequency
dependent impulse response. Intermediate values are automatically interpolated based on the
characteristics of the chosen post processing filters. Results are analysed and validated and
agreement with theoretical models is shown.

Citation

Sheaffer, J., Fazenda, B., Murphy, D., & Angus, J. (2011, June). A simple multiband approach for solving frequency dependent problems in numerical time domain methods. Presented at Forum Acusticum, Aalborg, Denmark

• Presentation Conference Type: Other
• Conference Name: Forum Acusticum
• Conference Location: Aalborg, Denmark
• Start Date: Jun 26, 2011
• End Date: Jul 1, 2011
• Publication Date: Jun 26, 2011
• Deposit Date: Jul 4, 2011
• Publicly Available Date: Apr 5, 2016
• Publisher URL: http://www.fa2011.org/
• Additional Information: Event Type : Conference