Interactive real-time auralization of airborne sound insulation in buildings

Abstract

Sound insulation auralization can be used as valuable tool to study the perceptual aspects of sound transmission in built environments for assessment of noise effects on people. It may help to further develop guidelines for building constructions. One advanced goal of real-time sound insulation auralization is to appropriately reproduce the condition of noise effects on the human perception and cognitive performance in dynamic and interactive situations. These effects depend on the kind of noise signal (i.e. speech, music, traffic noise, etc.) and on the context. This paper introduces a sound insulation auralization model. The sound insulation filters are constructed for virtual buildings with respect to complex sound propagation effects for indoor and outdoor sound sources. The approach considers the source room sound field with direct and diffuse components along with source directivity and position. The transfer functions are subdivided into patches from the source room to the receiver room, which also covers composite building elements, thus providing more detail to the actual building situations. Furthermore, the receiving room acoustics includes the reverberation of the room based on its mean free path, absorption and binaural transfer functions between its radiating walls elements and the listener. This more exact approach of sound insulation model agrees reasonably well with the ISO standard (i.e. diffuse field theory) under standard settings. It is also shown that the sound field significantly influences the transmitted energies via building elements depending on the directivity and position of the source. The proposed method is validated as a general scheme and includes more details for real-time auralization in specific situations especially in the cases where the simplified diffuse sound field approach fails. It is capable to be used in interactive Virtual Reality (VR) systems, which opens new opportunities for psychoacoustics research in noise effects on human.

Virtual Building Acoustics

“…ˆ ‡ , , L <. Subsequently, it is approximately equalised to a white spectrum and normalized in energy [47,80]…”

“…In Section 4.1, it was discussed auralization of sound insulation filters for simple adjacent rooms which is the starting point of the advanced auralization models [80]. In this extended approach, in first place, it is taken into account the source room acoustics by considering a more complex sound field incident on the source room walls consisting of a direct and a diffuse field component.…”

“…Let D(c) be source signal normalized in power and ℎ , (c) is energetically normalised impulse response of the source room calculated at a distance w from it by using Equation 4.9. Let the directivity of source in the direction of receiver point on wall is " , the time domain representation of Equation 4.9 is rewritten in the form of Equation 4.10 [47,80].…”

“…position of the receiver). Finally, the time domain representation of the binaural signal at receiver point is obtained by introducing room impulse response of the receiver room and the HRIR filters for each secondary source to the receiver depending on its position and orientation relative to the secondary sources [80].…”

“…All ℎ(c) are statistically valid for all points inside both the source and the receiving rooms that is why ℎ(c) can be synthesized before implementing the auralization filter chain. However, as it can be assumed that ℎ(c) does not vary significantly for different source/receiver positions, hence, ℎ Z, (c) and ℎ Z, (c) can be computed independently to avoid coherent interferences in the reverberant field coming from different radiating elements [80].…”