A study on the auralization system using flexible rendering for virtual reality-based acoustic simulation

摘要

It is not easy for architects to consider the effect of the acoustic environment of a plan in the early design phase because it requires great expertise to properly use acoustic simulation software. The importance of a room’s acoustics has increased, so a solution that makes the accessibility of acoustic design work for architects is demanded. We developed a kind of acoustic simulation system that can provide a service for architects using virtual reality technology. In this paper, we described how to implement real-time sound representation with the system, which is connected to the visual data of a virtual reality headset and the acoustic simulation. Although there have been many studies using virtual reality technologies in acoustic simulation that have been conducted for a long time, some limitations have been unresolved, such as cost and portability problems. This study tried to realize flexible rendering using vector base amplitude panning (VBAP) and multi-channel speakers with an auralization method. In this paper, we propose a system that implements spatial sound around one person by using 11 speakers and VBAP, and we made a prototype to verify system function. We applied an acoustic ray tracing algorithm by using the Unity game engine and MAX digital signal processing software to control multiple speakers at the same time for VBAP. The hardware part of this system consists of an audio interface, two digital to analog converters (DAC), 11 mono amplifiers, and 11 full-range loudspeakers. The three-dimensional layout of the loudspeakers was based on an icosahedron to maximize the performance of VBAP. We tested the prototype of the system to verify its effectiveness and confirmed the change of sound pressure level according to the distance from the sound source and the sound absorption coefficient of the wall. In a reliability test of the performance of sound image localization by human cognitive ability, the result was a match rate of 89.4%, which proved the usefulness of this system for sound simulation for architects with low cost and easy portability.