According to one embodiment, a sound emitting apparatus includes an elastic member, three or more excitation actuators, and a control circuit. The elastic member has an annular shape. The excitation actuators are arranged at a predetermined angular interval on the elastic member and are configured to apply vibration to the elastic member. The control circuit is configured to generate drive signals for driving the three or more excitation actuators. There is a phase difference between drive signals for two excitation actuators separated by the predetermined angular interval, the phase difference depending on an order of a Lobe mode being a vibration mode excited on the elastic member and the predetermined angular interval.

An active noise control device includes a secondary path filter coefficient updating unit. The secondary path filter coefficient updating unit is configured to update a coefficient of a secondary path filter by using a coefficient of the secondary path filter after previous updating as a previous value, when a phase characteristic of the secondary path filter that sets an initial value as the coefficient and a phase characteristic of the secondary path filter that uses the previous value as the coefficient are not approximate to each other.

Systems and methods for selectively providing audio alerts via a speaker device are disclosed herein. A system plays first audio content through a speaker. A microphone captures second audio content comprising an alert. Output of the second audio content through the speaker is suppressed by using noise cancellation. The system identifies the alert within the second audio content and determines a priority level of the alert. The system determines, based on the priority level, that the alert should be reproduced, and audibly reproduces the alert via the speaker, with the first audio content or instead of the first audio content.

A vehicle sound synthesis system is provided with a controller and a loudspeaker. The controller is programmed to receive an input indicative of at least one of a gear selection, an engine speed, and a pedal position and to generate an audio signal indicative of synthesized engine noise (SEN). The controller is further programmed to attenuate the audio signal at a first rate in response to at least one of the gear selection, the engine speed, and the pedal position indicating first vehicle conditions. The loudspeaker is adapted to project sound within a passenger compartment of a vehicle in response to receiving the attenuated audio signal.

An active noise reduction device includes: a reference signal input terminal that receives a reference signal from a reference signal source attached to an automobile; a simulated vibration transfer characteristics filter unit that generates a second signal by correcting, using simulated vibration transfer characteristics, a first signal for outputting, from a loudspeaker attached to the automobile, a sound different from a canceling sound, the simulated vibration transfer characteristics simulating vibration transfer characteristics from the loudspeaker to the reference signal source; a first subtracter that outputs a corrected reference signal obtained by subtracting the second signal generated, from the reference signal received by the reference signal input terminal; and an adaptive filter unit that applies an adaptive filter to the corrected reference signal outputted from the first subtracter to generate a canceling signal to be used to output the canceling sound.

Aspects of the disclosure relate to using a display as a sound emitter and may relate to an electronic device including a display. In particular a vibration sensor such as an accelerometer is physically coupled to the display and senses display vibration to provide a high accuracy feedback loop with respect to representing actual audio output from the display. The electronic device includes an actuator physically coupled to the display and configured to cause vibration of the display in response to an audio signal. The electronic device further includes a vibration sensor physically coupled to the display and configured to output a vibration sensor signal proportional to the vibration of the display due to the actuator. The electronic device further includes a processor operably coupled to the vibration sensor. The processor is configured to adjust the audio signal based on the vibration sensor signal from the vibration sensor.

A noise controlling method, comprising: generating one reference signal representing a primary noise; generating one secondary noise in response to a control signal, for cancelling the primary noise; generating one error signal representing a superposition of the primary noise and the secondary noise at a position. The method further comprises: generating at least one additional reference signal, and/or at least one additional secondary noise, and/or at least one additional error signal; and generating the control signal(s) for generating the secondary noise(s), by executing an adaptive subband filtering algorithm based on the reference signal(s) and the error signal(s); wherein the step of generating the control signal(s) comprises: decomposing the reference signal(s) and the error signal(s) into subband reference signal(s) and subband error signal(s), respectively, for each subband of a plurality of subbands; updating a subset of one or more subband adaptive filters for at least one subband of the plurality of subbands, based on a subset of the subband reference signal(s) of the at least one subband and a subset of the subband error signal(s) of the at least one subband, wherein at least one of said three subsets is a proper subset; updating at least one fullband adaptive filter based on the updated subband adaptive filter(s); generating the control signal(s) by filtering the reference signal(s) by the updated at least one fullband adaptive filter.

A active noise cancellation (ANC) system may include an adaptive filter divergence detector for detecting divergence of the one or more controllable filters as they adapt, based on various temporal or frequency domain amplitude characteristics. Upon detection of a controllable filter divergence, the ANC system may be deactivated, or certain speakers may be muted. Alternatively, the ANC system may modify the diverged controllable filters to restore proper operation of the noise cancelling system. This may include adjusting a leakage value of an adaptive filter controller.

A vehicle-implemented noise-cancellation system, includes: a noise-cancellation system disposed in a vehicle, the noise-cancellation system comprising an adaptive filter being adjusted according to a reference signal and an error signal, the adaptive filter outputting a noise-cancellation signal, which, when transduced into a noise-cancellation audio signal by a speaker, cancels road noise within at least one zone within a cabin of the vehicle; and an adjustment module configured to vary a power of the noise-cancellation signal or a rate of adaptation of the adaptive filter from a first value to a second value, passing through at least one intermediate value between the first value and the second value, based on a time-varying signal indicative of a signal-to-noise ratio of the reference signal with respect to a first criterion.

An engine harmonic cancellation system includes an accelerometer disposed within a vehicle to detect a harmonic produced by an engine of the vehicle and to produce a harmonic reference signal representative of the harmonic; a controller configured to produce a harmonic cancellation signal that, when transduced into an acoustic signal, cancels the harmonic within at least one cancellation zone within a cabin of the vehicle, wherein the harmonic cancellation signal is based, at least in part, on mixing the harmonic reference signal converted to baseband with a baseband signal output from a look up table; and a speaker disposed within the cabin and configured to receive the harmonic cancellation signal and to transduce the harmonic cancellation signal into an acoustic harmonic cancellation signal, such that the harmonic is cancelled within the cancellation zone.