Parrot

Devialet

Parrot Drones

Vu Hoang Co Thuy

Benoit Pochon

Phong Hua

Pierre Guiu

Artur Zorzo

Benoît Pochon

The headphones () comprise: a transducer () (); an noise-canceling processing chain () comprising: The secondary path is formed between the transducer () and the eardrum, and the transfer function of the processed secondary path is the transfer function of the secondary path combined with the transfer functions of the processing components, excluding the processing filter ().

Noise canceling headphones

The present invention relates to a device () for controlling a loudspeaker in an enclosure, the device () comprising:

Device for controlling a loudspeaker and associated sound reproduction facility

The headset includes an active noise control, with an internal ANC microphone () placed inside the acoustic cavity () and delivering a signal including an acoustic noise component. A digital signal processor DSP () comprises a feedback ANC branch () applying a filtering transfer function (, H) to the signal delivered by the ANC microphone, and a mixer () for mixing the signal of the feedback branch with an audio signal to be reproduced (M). The headset comprises a movement sensor () mounted on one of the earphones. The DSP comprises an anti-saturation module () for analyzing concurrently i) the signal delivered by the internal microphone () and ii) the signal delivered by the movement sensor (), and verifying whether current characteristics of these signals fulfill or not a set of predetermined criteria. Upstream from the feedback ANC filter (), an anti-saturation filter (, H) is selectively switched as a function of the result of this verification. The filtering of an equalization branch (, H) of the signal to be reproduced (M) is also modified by a similar anti-saturation filter (, H).

ANC noise active control audio headset with prevention of the effects of a saturation of the feedback microphone signal

The method comprises the determination of an observation vector that comprises only electrical measurements of the voltage (U) at the loudspeaker terminals and of the current (i) passing through the loudspeaker, and a state vector (X) whose components comprise: values of linear parameters of the loudspeaker response such as the electrical (R) and mechanical (R) resistance, and polynomial coefficients of nonlinear parameters such as the force factor (BI), the equivalent stiffness (K) and the electrical inductance (L). The voltage and current measurements are applied to an estimator with a predictive filter of the extended Kalman filter incorporating a representation of a dynamic model of the loudspeaker. This filter operates a prediction of the state vector (X) and readjusts this prediction by calculation of an estimate (U) of the voltage based on the state vector and on the measured current and comparison of this estimate with the measurement (U) of the voltage.

Method for processing an audio signal with modeling of the overall response of the electrodynamic loudspeaker

The method comprises the steps of: a) converting the digital audio signal (PCM) into a voltage signal (V); b) first lowshelf filtering of fixed gain (G); c) calculating a value of excursion (x) of the loudspeaker; d) comparing the excursion with a maximum value and calculating a first gain of possible attenuation (G); e) second lowshelf filtering of gain (G+G) taking into account the first gain of possible attenuation; g) comparing with the maximum saturation or clipping voltage (v) and calculating a second gain of possible attenuation (G); h) third lowshelf filtering gain (G+G+G) taking into account the first and/or second gains of possible attenuation; i) comparing with the maximum saturation or clipping voltage (v) and applying a gain of possible overall attenuation (G); j) optionally compensating for the nonlinearities of the loudspeaker response; and k) reversely converting the signal (V) into a digital audio signal (S) without dimension, for later amplification.

Method for enhancing low frequences in a digital audio signal

An automatic gain control system applied to a audio signal as a function of the ambient noise, the system comprising: an ambient noise estimator module suitable for establishing a current noise value estimated at least from a signal provided by a microphone; and an automatic gain control module suitable for applying to the audio signal gain of a value that is determined as a function of the current noise value received from the ambient noise estimator module. According to the invention, the ambient noise estimator module comprises an MCRA estimator suitable for establishing the current noise value from a signal provided by the microphone picking up the real noise, the echo of the music, and where appropriate speech. The system also includes a module for estimating the power of the audio signal and suitable for providing the automatic gain control module with a current power value for the audio signal.

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Paris, France

Vu Hoang Co Thuy