Brinks Gilson & Lione
Audio control device
A first fixed filter extracts high-frequency and low-frequency sound signals outside the audible band, and a level integrator integrates levels of the sound signals to obtain a first integrated value. With a second fixed filter, the level integrator integrates levels of sound signals in a low frequency band within the audible band to obtain a second integrated value. A control unit determines whether the high-frequency sound signals are dominant by comparing the first integrated value with the second integrated value. When the high-frequency sound signals are dominant, the control unit attenuates high-frequency speaker drive signals using a variable filter.
Alpine Electronics, Inc.
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Minoru Yoshikazu Masashi
Matsuyama Maeda Saito