Spatial Sound in Virtual Reality

1 Introduction

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Close your eyes, carefully listen to the sounds that surround you. Try to visualize where that bird’s song is coming from. Can you hear the sound of traffic in the background ? Or a plane crossing the sky from left to right? Perhaps those voices behind you or someone approaching at a fast pace draw your attention…

A sound scene can create an immersive experience for the listener without the need for images, smell or touch. Immersive sound can transport the listener to a different place giving her the sensation of being there. Virtual listening environments can be reproduced with speaker arrays or headphones. There are different techniques involving complex systems of reproduction but the simplest way to experience immersive sound is with a pair of headphones and a binaural recording 11Do not confuse binaural with binaural beats. A binaural beat is an auditory illusion perceived when two different pure tone sine waves, both with frequencies lower than 1500 Hz, with less than a 40 Hz difference between them, are presented to a listener dichotically (one through each ear). The word ‘binaural’ refers to hearing with two ears including spatial cues from the ears, head, and body of the listener..

Auditory spatial perception refers to the ability to localize individual sound sources in a real or virtual space. The main cues humans use to localize sound are the interaural time difference ITD, the interaural intensity difference IID, and the spectral shaping by the pinnae, whose convoluted structure changes the spectrum of the sound, thus acting as a filter 22Middlebrooks, J. C., & Green, D. M. (1991). Sound localization by human listeners. Annual Review of Psychology, 42(1), 13i5-159..