Abstract: A device for manipulating the exhaust outlet noise of a motor vehicle, having an exhaust flap which can be positioned in an exhaust pipe and which can be displaced in oscillatory fashion about an exhaust flap basic position in a defined angle range about the exhaust flap basic position in order to manipulate the exhaust outlet noise, wherein the exhaust flap basic position can be actively adjusted as a function of an engine rotational speed and/or an engine load, and wherein the angle range can be actively adjusted as a function of a frequency to be eliminated or attenuated, or a frequency to be generated or enhanced, of the exhaust outlet noise.

Abstract: The invention relates to a hair dryer including a tapered plastic shell between a rear end and a front end through which flows out the air set into motion and heated by the hair dryer, this plastic shell defining at least one air inlet and an air outlet and being intended to accommodate at least one motor and one fan, the shaft of which is borne by an attached internal structure in the central portion of the fuselage. According to the invention, the plastic shell is conformed in order to receive the air between the air inlet and the internal structure bearing the fan, on a longer acoustic path as compared with the length of the acoustic path between the rear end and the internal structure bearing the fan.

Abstract: A device for manipulating the exhaust outlet noise of a motor vehicle, having an exhaust flap which can be positioned in an exhaust pipe and which can be displaced in oscillatory fashion about an exhaust flap basic position in a defined angle range about the exhaust flap basic position in order to manipulate the exhaust outlet noise, wherein the exhaust flap basic position can be actively adjusted as a function of an engine rotational speed and/or an engine load, and wherein the angle range can be actively adjusted as a function of a frequency to be eliminated or attenuated, or a frequency to be generated or enhanced, of the exhaust outlet noise.

Abstract: The invention relates to a hair dryer including a tapered plastic shell between a rear end and a front end through which flows out the air set into motion and heated by the hair dryer, this plastic shell defining at least one air inlet and an air outlet and being intended to accommodate at least one motor and one fan, the shaft of which is borne by an attached internal structure in the central portion of the fuselage. According to the invention, the plastic shell is conformed in order to receive the air between the air inlet and the internal structure bearing the fan, on a longer acoustic path as compared with the length of the acoustic path between the rear end and the internal structure bearing the fan.

Abstract: The invention relates to a method and a device for passive and active acoustic reduction, including m electro-acoustic bars (41) side by side and separated by gaps (D), thus constituting an open-work acoustic barrier combining passive and active noise-reduction.

Abstract: The present invention relates to a device for attaching at least one acoustic panel (1) to a wall (P) characterized by having first attaching means (10) associated with wall (P) and second attaching means (20) associated with said acoustic panel(s) (1), said first (10) and second (20) attaching means being connected to each other by elastic connecting means (30). By adjusting the elasticity of the connecting means, the frequency of each acoustic panel can be individually tuned to treat the various sound frequency ranges. In addition, the device according to the invention enables the acoustic panels to be disconnected from the wall on which they are mounted, thus increasing the insulation of the room.

Abstract: The device for the active sound attenuation of a sound signal propagated in a duct comprises: at least first sensor means for a first sound signal, attenuation actuating means supplying an active sound attenuation signal in response to a selected control signal, an electronic control means generating the active sound attenuation signal for the actuating means. The first sensor means and the actuating means are arranged completely inside the duct opposite one another and at a selected distance from the casing of the duct, the axis of symmetry of the radiation of the actuating means and the axis of symmetry of the first sensor means are substantially parallel to the direction of propagation of the sound signal in the duct, and the actuating means are arranged upstream of the first sensor means in the direction of propagation of the sound signal in the duct.

Abstract: The device for the active sound attenuation of a sound signal propagated in a duct comprises: at least first sensor means for a first sound signal, attenuation actuating means supplying an active sound attenuation signal in response to a selected control signal, an electronic control means generating the active sound attenuation signal for the actuating means. The first sensor means and the actuating means are arranged completely inside the duct opposite one another and at a selected distance from the casing of the duct, the axis of symmetry of the radiation of the actuating means and the axis of symmetry of the first sensor means are substantially parallel to the direction of propagation of the sound signal in the duct, and the actuating means are arranged upstream of the first sensor means in the direction of propagation of the sound signal in the duct.

Abstract: A filtering device consisting of a nonadaptive feedback filter that generates active attenuation of the vibration on the framework, without generating instability in a first frequency band, and an adaptive feedforward filter is disclosed. Feedforward filtering coefficients are adapted in real time according to an algorithm chosen to minimize the energy of the types of vibration which are picked up by a sensing device as a function of the energy of the types of vibration which are picked up by the sensing device, and of the previously measured transfer function, in the presence of a feedback filtering device and in the absence of a feedforward filtering device, between an actuator device and a first sensing device. The device makes it possible to linearize the feedback attenuation throughout a second frequency band which is wider than the first frequency band, to accelerate the convergence of the minimization algorithm and to enhance the robustness of the feedforward filter.

Abstract: The invention concerns a loudspeaker having an elongate parallelepiped hollow body, whereof one longitudinal surface is made up of a stretched elongate rectangular planar diaphragm. The diaphragm is suspended by its edges to the body adjacent side surfaces, and is integral with an elongate rigid inner part extending in the body longitudinal direction, and bearing a mobile electromagnetic coil, parallel to the diaphragm. The coil is arranged between two fixed magnets located along the body two longitudinal side surfaces which form, with the base of said body, polar parts. Said loudspeaker is useful as component of an active anti-noise system, associated with a double glazing.

Abstract: A selected electrical signal is first applied to the input of a source (30) to determine at least the impulse response (H), over a predetermined time, between the source output and the input of sensors (20). The values of the active cancellation control signal are determined in real time according to a predetermined law established in accordance with the previously determined impulse response (H), whereby the energy of the output signal from the sensors is minimised. The acoustic structure (2) is arranged so that the space (534) containing the sensors (20) and the source (30) is invariant at least during the determination of the active cancellation control signal and in the presence of a person, whereby the impulse response (H) between the output of the source (30) and the input of the sensors (20) may remain invariant.

Abstract: The device for extracting a useful acoustic signal from a composite acoustic signal including nuisance components includes: first sensor component for picking up the composite acoustic signal; second sensor component for picking up, in real-time, the reference acoustic signal, which is substantially correlated with the nuisance components of the composite acoustic signal; adaptive filtering component; and extraction component. The coefficients of the filtering component are adapted in real time according to an algorithm chosen so as to minimize the energy of the composite acoustic signal as a function of the energy of the reference acoustic signal, until the signal leaving the output of the extraction component corresponds substantially to the useful acoustic signal selectively rid of the nuisance components.

Abstract: The present invention relates to a device for detecting and locating leaks of fluids circulating in a pipe system. The technical field of the invention is that of fluid leak detection devices. The device comprises a pick-up sensor not in contact with the pipe system, signal-processing means for processing the signals delivered by said pick-up sensor and headphones equipped with speakers supplied by said signal-processing means, said headphones further comprising a microphone connected to said signal-processing means, and said signal-processing means comprising electronic noise-reducing means.