Reduction of Bass-Reflex Port Nonlinearities by Optimizing the Port Geometry

Roozen NB, Vael JEM, Nieuwendijk JA. Reduction of Bass-Reflex Port Nonlinearities by Optimizing the Port Geometry. In: AES Convention 104. Audio Engineering Society; 1998. Paper 4661. Available from: https://aes.org/publications/elibrary-page/?id=8519

@inproceedings{Roozen1998_8519,
  author = {Roozen, N. B. and Vael, J. E. M. and Nieuwendijk, Joris A.},
  title = {{Reduction of Bass-Reflex Port Nonlinearities by Optimizing the Port Geometry}},
  booktitle = {AES Convention 104},
  note = {Paper 4661},
  year = {1998},
  month = may,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=8519}
}

TY  - CPAPER
TI  - Reduction of Bass-Reflex Port Nonlinearities by Optimizing the Port Geometry
AU  - Roozen, N. B.
AU  - Vael, J. E. M.
AU  - Nieuwendijk, Joris A.
T2  - AES Convention 104
M1  - Paper 4661
PY  - 1998
DA  - 1998/05/06
UR  - https://aes.org/publications/elibrary-page/?id=8519
PB  - Audio Engineering Society
LA  - en
AB  - Bass-reflex ports are used to enhance the bass reproduction of loudspeakers. However, at higher output levels, the bass-reflex port nonlinearities, specifically the unsteady separation of the acoustic flow, can lead to blowing sounds and acoustic losses. Calculations and measurements are presented for a number of port geometries. The effect of rounding the port terminations and the effect of converging-diverging ports on the production of blowing sounds are investigated. It appears that the intensity of the unsteady separation of the acoustic flow, as well as the radiation efficiency of the port and the quality factor of the port resonances, altogether determine the level of blowing noise. Maximum reduction of the blowing sounds and acoustic losses is obtained by using a port contour geometry that slowly diverges from the center towards both port ends and is rounded with curvature radii that are not too large at both port terminations.
ER  -