The effect of spatial energy spread on sound image size and speech intelligibility

Abstract

This study explored the relationship between perceived sound image size and speech intelligibility for sound sources reproduced over loudspeakers. Sources with varying degrees of spatial energy spread were generated using ambisonics processing. Young normal-hearing listeners estimated sound image size as well as performed two spatial release from masking (SRM) tasks with two symmetrically arranged interfering talkers. Either the target-to-masker ratio or the separation angle was varied adaptively. Results showed that the sound image size did not change systematically with the energy spread. However, a larger energy spread did result in a decreased SRM. Furthermore, the listeners needed a greater angular separation angle between the target and the interfering sources for sources with a larger energy spread. Further analysis revealed that the method employed to vary the energy spread did not lead to systematic changes in the interaural cross correlations. Future experiments with competing talkers using ambisonics or similar methods may consider the resulting energy spread in relation to the minimum separation angle between sound sources in order to avoid degradations in speech intelligibility.

Sound source localization in virtual reality with ambisonics sound reproduction

“…Increasing the ambisonics order further, however, did not improve localization much, again in line with previous studies [14]. Similar effects of the ambisonics order have also been shown for speech intelligbility [11].…”

“…In its basic form (1 st order ambisonics), four channels corresponding to the first four spherical harmonics are used to encode the sound field. However, additional spherical harmonics can be included to improve the directional resolution of the reproduction [9][10][11], referred to as higher-order ambisonics (HOA). To accurately reproduce the encoded sound field, the number of loudspeakers should match the number of spherical harmonics used for the encoding.…”

Speech intelligibility with various head-related transfer functions: A computational modeling approach

“…Houtgast et al , 1980; Plomp, 1976). Reverberation has been shown to mask spectral differences in impulse responses (Ahrens et al , 2020; Oreinos and Buchholz, 2015). Furthermore, individual perception differences (e.g.…”

Ambisonics Sound Source Localization With Varying Amount of Visual Information in Virtual Reality

“…The individual loudspeakers used to reproduce each Ambisonics order are indicated in Figure 2. An Ambisonics decoder with dual-band energy normalization was used as in (Favrot & Buchholz, 2010) and (Ahrens et al, 2020). The low-frequency region received no weighting (basic decoding) and in the high-frequency region 'max-re' decoding was applied.…”

“…In its basic form (1st-order Ambisonics), four channels corresponding to the first four spherical harmonics are used to encode the sound field. However, additional spherical harmonics can be included to improve the directional resolution of the reproduction (Gerzon, 1973;Bertet et al, 2013;Ahrens et al, 2020), referred to as higherorder Ambisonics (HOA). To accurately reproduce the encoded sound field, the number of loudspeakers should match the number of spherical harmonics used for the encoding.…”