A fast and accurate adaptive-filter method to measure directivity of loudspeakers

Nakamura S, Enzner G, Fallah A, van de Par S. A fast and accurate adaptive-filter method to measure directivity of loudspeakers. In: Express Paper. Audio Engineering Society; 2024. Paper 233. Available from: https://aes.org/publications/elibrary-page/?id=22579

@inproceedings{Nakamura2024_22579,
  author = {Nakamura, Shun and Enzner, Gerald and Fallah, Ali and van de Par, Steven},
  title = {{A fast and accurate adaptive-filter method to measure directivity of loudspeakers}},
  note = {Paper 233},
  year = {2024},
  month = jun,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=22579}
}

TY  - CPAPER
TI  - A fast and accurate adaptive-filter method to measure directivity of loudspeakers
AU  - Nakamura, Shun
AU  - Enzner, Gerald
AU  - Fallah, Ali
AU  - van de Par, Steven
M1  - Paper 233
PY  - 2024
DA  - 2024/06/06
UR  - https://aes.org/publications/elibrary-page/?id=22579
PB  - Audio Engineering Society
LA  - en
AB  - In audio engineering, the speed and precision of loudspeaker directivity measurement is intrinsic to product development. Conventional methods for individual measurements are time consuming and may delay progress in loudspeaker design and evaluation. Our novel approach speeds up this process without sacrificing accuracy, using standard lab equipment of existing configurations. By utilizing a continuously rotating loudspeaker, our method quickly generates a full 360-degree directivity map, significantly reducing the conventional time required for comprehensive assessments. Our method uses the Normalized Least Mean-Square (NLMS) adaptive filter algorithm to identify rotating impulse responses and to reject turntable noise. In doing so, it delivers nearly infinite spatial resolution in the azimuth direction, thus offering detailed insights into loudspeaker performance across angles and frequencies. Extensive analysis with two fundamentally different loudspeaker devices confirms our methods effectiveness, allowing for rapid directivity evaluations in about a minute, which is a drastic improvement over the hours needed with traditional approaches. This advancement facilitates quicker product iterations and design, leading to enhanced acoustic quality in audio products from smart speakers to mobile devices.
ER  -