A method of masking road noise for a vehicle includes monitoring, through a processor, one or more vehicle mounted transducers for noise produced by an interaction between the vehicle and a road surface, detecting, through the processor, an audible signal having one of an undesirable frequency and an undesirable magnitude associated with the interaction between the vehicle and the road surface, generating, through the processor, a masking signal having a frequency that will mask the audible signal having the one of the undesirable frequency and undesirable magnitude, and emitting the masking signal through one or more vehicle speakers.

In-car communication and hands-free talking with good sound quality are realized. An echo cancelation apparatus (4) is for use in a vehicle in which microphones (M1, M2) and loudspeakers (S1, S2) are disposed in acoustic regions (100, 200). A loudspeaker (S1) and a microphone (M1) are disposed in a first acoustic region (100), and a loudspeaker (S2) and a microphone (M2) are disposed in a second acoustic region (200). An acoustic signal picked up by the microphone (M1) disposed in the first acoustic region (100) is emitted from the loudspeaker (S2) disposed in the second acoustic region (200). An acoustic signal picked up by the microphone (M2) disposed in the second acoustic region (200) is emitted from the loudspeaker (S1) disposed in the first acoustic region (100). The microphone (M1) is designed to hardly collect a sound emitted from the loudspeaker (S2).

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.

An active noise control device performs signal processing on a basic signal corresponding to a control target frequency by a control filter, which is an adaptive notch filter, to generate a control signal that controls a speaker, sequentially and adaptively updates coefficients of the control filter, compares a magnitude of a primary path filter with a magnitude of the control filter, and determines whether the state of the control filter is unstable or not.

An acoustic noise suppressing apparatus includes a sound pickup circuit, a first and second suppression circuits, and an output signal selection circuit. The sound pickup circuit picks up sound. The first suppression circuit processes the sound, in which the first suppression circuit is configured to calculate a first suppression sound signal in which acoustic noise is suppressed from the sound by using a first algorithm suitable for multiple sound sources. The second suppression circuit processes the audio signal in parallel with the first suppression circuit, in which the second suppression circuit is configured to calculate a second suppression sound signal in which acoustic noise is suppressed from the sound signal by using a second algorithm suitable for a single sound source. The output signal selection circuit outputs only one of the first suppression audio signal and the second suppression audio

An active noise control device includes a first adaptive filter configured to generate a control signal by performing a filtering process on a reference signal corresponding to noise, and a first filter coefficient updating unit configured to update a filter coefficient of the first adaptive filter based on based on the reference signal and an added error signal acquired by adding a first error signal acquired by detecting residual noise by a first microphone and a second error signal acquired by detecting residual noise by a second microphone.

A method and an apparatus for active noise suppression in a vehicle. The apparatus includes an actuator in the vehicle and a part of the vehicle. The part of the vehicle is designed according to a first transfer function, which characterizes a transmission behavior of the part of the vehicle for sound. At least a part of the actuator is configured according to a second transfer function, which characterizes a transmission behavior of the at least one part for sound. The actuator is controllable in dependence on a control variable for active noise suppression.

Noise abatement within a signal stream containing unwanted signal referred to as noise is performed by acquiring a digitized noise signal and using a digital processor circuit to subdivide the acquired noise signal into different frequency band segments and thereby generate a plurality of segmented noise signals. Then individually for each segmented noise signal, the processor shifts in time the segmented noise signal by an amount dependent on a selected frequency of the segmented noise signal to produce a plurality of shifted segmented noise signals. The precise time shift applied to each noise segment considers the frequency content of the segment and the system processing time. Individually for each segmented noise signal, amplitude scaling is applied. The shifted and amplitude-scaled segmented noise signals are then combined to form a composite anti-noise signal which is output into the signal stream to abate the noise through destructive interference.

Provided is an information processor including a signal processing section that acquires a first signal to be detected by an acoustic input section of a first unit including the acoustic input section disposed within a predetermined distance from one ear hole of a user in a state of being worn by the user, acquires a second signal, which indicates a noise generated from a noise source, to be acquired by a second unit, and generates a noise cancellation signal directed to the noise on the basis of the first signal and the second signal.

Noise cancellation systems and methods are provided that receive a reference signal representative of a noise to be reduced and provide a noise cancellation signal based upon the reference signal. Some examples include a feedback signal representative of a residual noise in the environment. At least one of the reference signal, the noise cancellation signal, or the feedback signal is filtered to remove components based upon a rotational rate of a rotating equipment associated with the environment, such as an engine of a vehicle. Accordingly, the noise cancellation system may not interfere with sounds related to the engine.