- Reliable mechanical and thermal protection
- Exploits the entire voice coil swing
- Minimum artifacts
- Zero latency possible
Electro-mechanical transducers need active protection against mechanical overload at high excursion and against thermal overload at high input power to avoid excessive audible distortion or even destruction. The nonlinear and thermal modeling combined with the permanent parameter identification of KCS provide a very accurate displacement and voice coil temperature estimation. Thus, the protection system can anticipate critical situations and attenuate signal components to prevent overload.
While the thermal protection reduces the level of the entire input signal to reduce the electrical power, the mechanical protection system only attenuates low frequencies where the voice coil excursion is high. Hence the maximum allowed excursion is fully utilized because the audio level can still be increased while only the excursion is restrained. This technique allows the transducer to be reliably protected without latency and avoids artifacts generated by compressors and limiters that impair the perceived sound quality.
The video shows the impact of the mechanical protection system. A music stimulus is applied to the speaker at maximally allowed excursion level. When the signal amplitude is further increased the excursion limit is not exceeded but the mean SPL is still enhanced. The activation of the mechanical protection as well as the influence on the sound pressure output is observable in the video.