Reproducing various wavefronts at low frequencies in a rectangular closed space using room-mode matching with DCT

Maeda N, Haneda Y. Reproducing various wavefronts at low frequencies in a rectangular closed space using room-mode matching with DCT. In: AES Convention 154. Audio Engineering Society; 2023. Paper 78. Available from: https://aes.org/publications/elibrary-page/?id=22103

@inproceedings{Maeda2023_22103,
  author = {Maeda, Natsuko and Haneda, Yoichi},
  title = {{Reproducing various wavefronts at low frequencies in a rectangular closed space using room-mode matching with DCT}},
  booktitle = {AES Convention 154},
  note = {Paper 78},
  year = {2023},
  month = may,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=22103}
}

TY  - CPAPER
TI  - Reproducing various wavefronts at low frequencies in a rectangular closed space using room-mode matching with DCT
AU  - Maeda, Natsuko
AU  - Haneda, Yoichi
T2  - AES Convention 154
M1  - Paper 78
PY  - 2023
DA  - 2023/05/06
UR  - https://aes.org/publications/elibrary-page/?id=22103
PB  - Audio Engineering Society
LA  - en
AB  - Sound field reproduction, a technology that reproduces a desired sound field over a specific area, has been gaining considerable attention in recent years; however, several practical issues exist, such as the degradation of the spatial reproduction accuracy due to room reflections. In this study, we propose room-mode matching at low frequencies using a discrete cosine transform (DCT) for rectangular rooms. The complex modal coefficients obtained by the DCT of the desired sound field are matched with the coefficients of the sound field to be reproduced by the loudspeaker array. We conduct simulations in two-dimensional rooms surrounded by non-rigid walls with a rectangular loudspeaker array covering the entire room, reproducing two control regions: one for the entire room and the other for a specific area. First, we determine the possibility of reproducing the propagating plane waves over an entire room using the proposed method. The simulation results indicate that the proposed approach is practical not only in terms of the reproduction accuracy but also in terms of loudspeaker filter gains. Subsequently, we study the possibility of reproducing the desired sound field in a specific region by applying a spatial window to the desired sound field, performing DCT expansion, and matching the modal coefficients. For example, we confirm that spherical waves radiating from a focused sound source can be reproduced by applying a spatial window outside the focused sound source.
ER  -