Comfortability analysis of immersive sound playback system for cabin noise based on frontal lobe fNIRS experiment: an application of 4th order ambisonics

Lee Y, Oh YS, Song W, Hong J. Comfortability analysis of immersive sound playback system for cabin noise based on frontal lobe fNIRS experiment: an application of 4th order ambisonics. In: Express Paper. Audio Engineering Society; 2026.pp. 461:1-. Available from: https://aes.org/publications/elibrary-page/?id=23271

@inproceedings{Lee2026_23271,
  author = {Lee, Yonghee and Oh, Yong Suk and Song, Wooseok and Hong, Jiyoung},
  title = {{Comfortability analysis of immersive sound playback system for cabin noise based on frontal lobe fNIRS experiment: an application of 4th order ambisonics}},
  pages = {461:1-},
  year = {2026},
  month = may,
  publisher = {Audio Engineering Society},
  url = {}
}

TY  - CPAPER
TI  - Comfortability analysis of immersive sound playback system for cabin noise based on frontal lobe fNIRS experiment: an application of 4th order ambisonics
AU  - Lee, Yonghee
AU  - Oh, Yong Suk
AU  - Song, Wooseok
AU  - Hong, Jiyoung
SP  - 1
M1  - Paper 461
PY  - 2026
DA  - 2026/05/28
UR  - https://aes.org/publications/elibrary-page/?id=23271
PB  - Audio Engineering Society
LA  - en
AB  - This study introduces a fourth-order ambisonic-based decoding system to reproduce railway cabin running noise in a studio environment, enabling enhanced spatial impression and detailed sound field variation. Real-world operational noise was recorded using a multichannel fourth-order Ambisonics microphone (Eigenmike EM32, mh acoustics LLC, USA), and the reproduced sound field was implemented through a multichannel loudspeaker system. The reproduced signals were quantitatively compared with the original operational noise in terms of spectral variation and waveform distortion. To further evaluate cabin acoustic characteristics using brain-response-based quantitative metrics, additional analyses were conducted employing a Sound Quality Index (SQI) and functional near-infrared spectroscopy (fNIRS). The playback system consisted of a 21.1-channel configuration, comprising four upper, twelve middle, and five lower loudspeakers. Waveform distortion relative to the original sound was analyzed under varying panning strategies. For spatial resolution assessment, angular resolutions of 22.5, 30, and 45 were applied. As the angular resolution decreased, precise directional rendering became more challenging; however, approximate directional localization was successfully achieved in most cases. For brain-response-based noise comfort evaluation, comparative experiments were conducted using SQI metrics and fNIRS measurements under operational noise conditions. Diffusion optical tomography (DOT) data obtained during increasing Loudness and Sharpness SQI regions were trained using a Faster R-CNNbased model to identify neural patterns associated with increasing discomfort.
ER  -