Directional sound field decay analysis in performance spaces

Abstract

The analysis of the spatio-temporal features of sound fields is of great interest in the field of room acoustics, as they inevitably contribute to a listeners impression of the room. The perceived spaciousness is linked to lateral sound incidence during the early and late part of the impulse response which largely depends on the geometry of the room. In complex geometries, particularly in rooms with reverberation reservoirs or coupled spaces, the reverberation process might show distinct spatio-temporal characteristics. In the present study, we apply the analysis of directional energy decay curves based on the decomposition of the sound field into a plane wave basis, previously proposed for reverberation room characterization, to general purpose performance spaces. A simulation study of a concert hall and two churches is presented uncovering anisotropic sound field decays in two cases and highlighting implications for the resulting temporal evolution of the sound field diffuseness.

Common-slope modeling of late reverberation

“…Previous studies have often reported directional or spatial variations of sound energy decay, decay times or reverberation times [28]- [36], [38]. While this sounds at first like a contradiction compared to our proposed common-slope analysis approach, two explanations for the compatibility of previous study results and our approach are given in the following.…”

“…Directional sound energy decay variations can be quantified in terms of directional EDFs (DEDFs), as proposed by Berzborn and Vorländer [38]. To this end, we use beamformers with axisymmetric analysis patterns and steer them to different directions, thus obtaining directionally constrained beamformer outputs that can be used to calculate DEDFs.…”

“…Previous investigations have often quantified late reverberation variations in terms of ISO 3382 parameters [26], [27] like reverberation time, early decay time, or clarity [28]- [35]. Some studies have also explored variations of multiexponential decay parameters [36], [37] or entire energy decay functions [38]. Overall, previous studies investigated both spatial [28]- [30], [33]- [36] and directional [31], [32] variations of late reverberation, and found effects of various magnitudes.…”

A Method for Capturing and Reproducing Directional Reverberation in Six Degrees of Freedom

“…However, rooms lacking good diffusion properties exhibit inhomogeneous and anisotropic decay of sound [4], [15]. Recent work has proposed novel ways to analyze decaying sound fields [16]- [19] while directional decay char-acteristics have also been found to be perceptually important once a certain threshold is met [20], [21].…”

Relation between Direction-of-Arrival distribution of reflected sounds in late reverberation and room characteristics: Geometrical acoustics investigation

“…Recent studies have reported that DoA distribution of late reverberation is not isotropic in real measurements using C-C method [6,7] or plane wave decomposition [8,9]. In late reverberation, many sound waves arrive simultaneously or at very close intervals.…”