If the excursion limit of the diaphragm of a speaker is exceeded, the speaker exhibits nonlinear behavior which manifests as distorted sound and degraded acoustic echo cancelation (AEC) performance. Moreover, if a speaker is driven too hard, the resulting excessive heat can damage the voice-coil and speaker. While the aforementioned problems are present in speakers of all sizes, these become more acute for smaller, portable speakers, e.g., as used in smartphones, smart speakers, micro-speaker, wearable devices, etc.

This disclosure describes techniques to simultaneously protect the speaker and achieve an optimum, multi-band audio experience by modeling the speaker, dynamically adjusting the excursion, and driving the speaker to its true limit while avoiding non-linear distortion. Per the techniques, real-time variations in the speaker are directly sensed, and feedforward and feedback control procedures are applied to deliver an optimum sound performance while maintaining safe speaker operating conditions.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.