The Use of Negative Source Impedance with Moving Coil Loudspeaker Drive Units: A Review and Analysis

Turner MJ, Wilson DA. The Use of Negative Source Impedance with Moving Coil Loudspeaker Drive Units: A Review and Analysis. In: AES Convention 122. Audio Engineering Society; 2007. Paper 7072. Available from: https://aes.org/publications/elibrary-page/?id=14057

@inproceedings{Turner2007_14057,
  author = {Turner, Michael J. and Wilson, David A.},
  title = {{The Use of Negative Source Impedance with Moving Coil Loudspeaker Drive Units: A Review and Analysis}},
  booktitle = {AES Convention 122},
  note = {Paper 7072},
  year = {2007},
  month = may,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=14057}
}

TY  - CPAPER
TI  - The Use of Negative Source Impedance with Moving Coil Loudspeaker Drive Units: A Review and Analysis
AU  - Turner, Michael J.
AU  - Wilson, David A.
T2  - AES Convention 122
M1  - Paper 7072
PY  - 2007
DA  - 2007/05/06
UR  - https://aes.org/publications/elibrary-page/?id=14057
PB  - Audio Engineering Society
LA  - en
AB  - The effect of negative source impedance on the frequency response and pole-zero pattern of a moving coil loudspeaker drive unit is explored from first principles, and closed form expressions for the transfer function and system poles are developed. Direct control of motor velocity via the substantial cancellation of voice coil impedance is discussed. Implementation using positive current feedback is analyzed, considering loop gain, damping and stability from a control theory perspective. Pole placement techniques are shown to be effective in controlling theoretical system behavior at high frequencies. Modeled and measured results are presented. A selection of previous papers and applications concerned with operation of loudspeakers from negative source impedances is briefly reviewed. Practical issues and some possible applications are discussed.
ER  -