Considerations for including surface scattering in room-acoustics auralization

Abstract

Recent research in auralization has centered on including wave-theoretical aspects that are unaccounted for by well-developed but frequency-limited geometrical models [Dalenbäck et al., J. Audio Eng. Soc. 42(10) (1994)]. For example, inclusion of edge diffraction (or edge scattering) has been shown (via scale-model measurements and listening tests) to contribute audibly to the early part of the room impulse response [Torres and Kleiner, Proc. 16th Intl. Congress on Acoust. (1998)]. Modeling room surface scattering requires consideration of at least two main concerns: (1) characteristics of typical room surfaces and (2) types of numerical models most suitable for reasonable speed and accuracy. Typical room surfaces (e.g., in concert halls) can have a periodic nature at one wave number-scale and a statistical nature at another. This suggests use of a multiscale, multiple-scattering description possibly based on a combination of perturbation models, ‘‘boss’’ models, variational models, or higher-order Kirchhoff theory. It may also require simplified surface-descriptors like those used for random rough surfaces. The second main concern influences the form of the model (e.g., time-domain versus frequency-domain formulations, chosen surface parameters) and its usefulness for auralization programs. Possible models are discussed with their respective applicability to room acoustics auralization. [Work supported by Johnsons Stiftelse and Teknikbrostiftelsen.]

Validation of the Numerical Simulation of the Scattered Sound Field With a Geometrical Pyramid Tracing Approach

“…On the other hand, as demonstrated by the picture above, the new formulation produces realistic impulse responses, where also the first-order reflections are always followed by a diffuse tail. as it always happen with measured impulse responses [11].…”

An Initial Investigation of the Audibility of Diffusion in Auralization

“…diffusion not varied below the 125 Hz octave but previous studies on including edge-diffraction in auralization [2] have shown that addition of edge-diffraction is audible in this range. Future subjective tests should also employ more accurate scattering models like those discussed in [4] Or perhaps higher-order diffusion models [11].…”

“…and auralization of various types of surface scattering via scale-model measurements [1][2][3]. This paper stems from a presentation of potential scattering models for room auralization [4] and discusses the subjective tests in detail. What kinds of approximations can be made to complex scattering models, while still retaining accurate auralization?…”