Active Loudspeaker Heat Protection

Tassart S, Valcin S, Menu M. Active Loudspeaker Heat Protection. J Audio Eng Soc. 2014;62(11):767-775. doi:10.17743/jaes.2014.0041

@article{Tassart2014_17551,
  author = {Tassart, Stéphan and Valcin, Simon and Menu, Michel},
  title = {{Active Loudspeaker Heat Protection}},
  journal = {Journal of the Audio Engineering Society},
  volume = {62},
  number = {11},
  pages = {767--775},
  year = {2014},
  month = nov,
  publisher = {Audio Engineering Society},
  doi = {10.17743/jaes.2014.0041},
  url = {https://doi.org/10.17743/jaes.2014.0041}
}

TY  - JOUR
TI  - Active Loudspeaker Heat Protection
AU  - Tassart, Stéphan
AU  - Valcin, Simon
AU  - Menu, Michel
T2  - Journal of the Audio Engineering Society
J2  - J. Audio Eng. Soc.
VL  - 62
IS  - 11
SP  - 767
EP  - 775
PY  - 2014
DA  - 2014/11/06
DO  - 10.17743/jaes.2014.0041
UR  - https://doi.org/10.17743/jaes.2014.0041
PB  - Audio Engineering Society
LA  - en
AB  - Because of the intrinsic inefficiency in loudspeakers, most electrical energy is converted into heat with a corresponding rise in temperature of the driver structure. To avoid the harmful effects of elevated temperatures on the voice coil, an active heat control (AHC) process limits the electrical signal when the temperature nears the danger limit. Typical AHC using a closed-loop approach can produce oscillations and audible artifacts because of sensor delays. This paper demonstrates that an open-loop AHC can work. A bounded voice-coil temperature can be achieved using a dynamic range compressor configured as a brick-wall limiter with a threshold that is controlled by the temperature of magnetic components. The temperature of the magnetic assembly and the driving force of the loudspeaker can both be estimated in real-time by a linear quadratic observer (a Kalman filter) and an envelope follower respectively. The new AHC scheme is compared to closed-loop AHC using a simulation example.
ER  -