Low Impedance Voice Coils for Improved Loudspeaker Efficiency

Iversen NE, Knott A, Andersen MAE. Low Impedance Voice Coils for Improved Loudspeaker Efficiency. In: AES Convention 139. Audio Engineering Society; 2015. Paper 9389. Available from: https://aes.org/publications/elibrary-page/?id=17946

@inproceedings{Iversen2015_17946,
  author = {Iversen, Niels Elkjær and Knott, Arnold and Andersen, Michael A. E.},
  title = {{Low Impedance Voice Coils for Improved Loudspeaker Efficiency}},
  booktitle = {AES Convention 139},
  note = {Paper 9389},
  year = {2015},
  month = oct,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=17946}
}

TY  - CPAPER
TI  - Low Impedance Voice Coils for Improved Loudspeaker Efficiency
AU  - Iversen, Niels Elkjær
AU  - Knott, Arnold
AU  - Andersen, Michael A. E.
T2  - AES Convention 139
M1  - Paper 9389
PY  - 2015
DA  - 2015/10/06
UR  - https://aes.org/publications/elibrary-page/?id=17946
PB  - Audio Engineering Society
LA  - en
AB  - In modern audio systems utilizing switch-mode amplifiers the total efficiency is dominated by the rather poor efficiency of the loudspeaker. For decades voice coils have been designed so that nominal resistances of 4 to 8 Ohms is obtained, despite modern audio amplifiers, using switch-mode technology, can be designed to much lower loads. A thorough analysis of the loudspeaker efficiency is presented and its relation to the voice coil fill factor is described. A new parameter, the drivers mass ratio, is introduced and it indicates how much a fill factor optimization will improve a driver’s efficiency. Different voice coil winding layouts are described and their fill factors analyzed. It is found that by lowering the nominal resistance of a voice coil, using rectangular wire, one can increase the fill factor. Three voice coils are designed for a standard 10” woofer and corresponding frequency responses are estimated. For this woofer it is shown that the sensitivity can be improved approximately 1 dB, corresponding to a 30% efficiency improvement, just by increasing the fill factor using a low impedance voice coil with rectangular wire.
ER  -