Force Factor Modulation in Electro Dynamic Loudspeakers

Risbo L, Agerkvist FT, Tinggaard C, Halvorsen M, Putzeys B. Force Factor Modulation in Electro Dynamic Loudspeakers. In: AES Convention 141. Audio Engineering Society; 2016. Paper 9607. Available from: https://aes.org/publications/elibrary-page/?id=18411

@inproceedings{Risbo2016_18411,
  author = {Risbo, Lars and Agerkvist, Finn T. and Tinggaard, Carsten and Halvorsen, Morten and Putzeys, Bruno},
  title = {{Force Factor Modulation in Electro Dynamic Loudspeakers}},
  booktitle = {AES Convention 141},
  note = {Paper 9607},
  year = {2016},
  month = sep,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=18411}
}

TY  - CPAPER
TI  - Force Factor Modulation in Electro Dynamic Loudspeakers
AU  - Risbo, Lars
AU  - Agerkvist, Finn T.
AU  - Tinggaard, Carsten
AU  - Halvorsen, Morten
AU  - Putzeys, Bruno
T2  - AES Convention 141
M1  - Paper 9607
PY  - 2016
DA  - 2016/09/06
UR  - https://aes.org/publications/elibrary-page/?id=18411
PB  - Audio Engineering Society
LA  - en
AB  - The relationship between the non-linear phenomenon of “reluctance force” and the position dependency of the voice coil inductance was established in 1949 by Cunningham, who called it “magnetic attraction force.” This paper revisits Cunningham’s analysis and expands it into a generalized form that includes the frequency dependency and applies to coils with non-inductive (lossy) blocked-impedance. The paper also demonstrates that Cunningham’s force can be explained physically as a modulation of the force factor that again is directly linked to modulation of the flux of the coil. A verification based on both experiments and simulations is presented along discussions of the impact of force factor modulation for various motor topologies. Finally, it is shown that the popular L2R2 coil impedance model does not correctly predict the force unless the new analysis is applied.
ER  -