Abstract: The invention relates to an installation having at least one caisson positioned at a given depth in a marine environment, said caisson including a rigid tank in which an oscillating plate moves, said oscillating plate being adapted to oscillate in relation to a vertical axis depending on fluctuations in the height of the water column created by the swell perpendicular to the plate, said tank and plate defining a chamber. The installation is characterized in that the chamber is sealed by a flexible hermetic pouch which is filled with a gas and deforms according to the oscillations of the oscillating plate, the pressure of the gas inside the pouch being adjusted so as to compensate for all or part of the weight of the water column perpendicular to the plate in the absence of swell.

Abstract: A multi-glazed window formed by a frame produced from profiles supporting at least two glass panes separated by an air layer. The window incorporating an active noise reduction device for a noise coming from a noise source. At least one loudspeaker an actuator associated with the membrane, which actuator is capable of inducing a vibratory movement of said membrane, at least one control microphone carried by the frame, said microphone being installed in the air layer in order to sense the acoustic signals in said air layer, and a control electronics suitable for controlling the actuator according to the acoustic signals sensed by the control microphone.

Abstract: An apparatus for natural ventilation of a room, including a room, at least one door or one window that has an opening frame produced by profiles supporting at least one glass panel, which opening frame is mounted so as to move in a fixed stationary frame formed by profiles surrounding said opening frame, a ventilation passage which communicates between the outside of the room and the inside of the room in such a way as to allow natural ventilation between the outside and inside of said room, and a noise absorber capable of attenuating sound waves propagating in the ventilation passage.

Abstract: An apparatus for natural ventilation of a room, with a room delimited by walls, at least one door or one window installed in one of the room walls, a ventilation passage which is fitted to the door or the window and which communicates between the outside of the room and the inside of said room in such a way as to allow natural ventilation between the outside and inside of said room, the passage having a first end opening into the room and a second end opening to the outside of said room, and a noise absorber capable of attenuating sound waves propagating in the ventilation passage, the attenuation being realized by the generation of a counter-noise which is superimposed on said sound waves or by absorbing all or part of said sound waves.

Abstract: A multi-glazed window incorporating an active or passive noise reduction device, with at least one vibrating membrane disposed between two adjacent glass panes in such a way as to vibrate in the air layer separating the two glass panes. The device includes a hollow body with two longitudinal side walls and one face of which is constituted at least partially by the membrane suspended at the side walls, on either side of same. The membrane has two distal edges at each of which is arranged an attachment member, which attachment member engages with a complementary attachment member arranged on a respective side wall of the body.

Abstract: An apparatus for natural ventilation of a room, with a room delimited by walls. At least one door or one window includes a fixed stationary frame surrounding a movable opening frame, a ventilation passage provided on the door or the window and which communicates between the outside of the room and the inside of the room in such a way as to allow natural ventilation between the outside and inside of said room, and a noise absorber capable of attenuating sound waves propagating in the ventilation passage, the attenuation being realized by the generation of a counter-noise which is superimposed on the sound waves or by absorbing all or part of said sound waves.

Abstract: A multi-glazed window formed by a frame produced from profiles supporting at least two glass panes separated by an air layer. The window incorporating an active noise reduction device for a noise coming from a noise source. At least one loudspeaker an actuator associated with the membrane, which actuator is capable of inducing a vibratory movement of said membrane, at least one control microphone carried by the frame, said microphone being installed in the air layer in order to sense the acoustic signals in said air layer, and a control electronics suitable for controlling the actuator according to the acoustic signals sensed by the control microphone.

Abstract: The invention relates to an installation having at least one caisson positioned at a given depth in a marine environment, said caisson including a rigid tank in which an oscillating plate moves, said oscillating plate being adapted to oscillate in relation to a vertical axis depending on fluctuations in the height of the water column created by the swell perpendicular to the plate, said tank and plate defining a chamber. The installation is characterised in that the chamber is sealed by a flexible hermetic pouch which is filled with a gas and deforms according to the oscillations of the oscillating plate, the pressure of the gas inside the pouch being adjusted so as to compensate for all or part of the weight of the water column perpendicular to the plate in the absence of swell.

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 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 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 invention relates to an electroaeroacoustic source (2) placed in a flow (V) or at the edge of a flow, consisting of an electrodynamic or electromagnetic motor means (5) generating an oscillating motion, and an element (3) coupled to the motor means (5) obstructing the flow so as to exert a dynamic action on said flow. This source can be used to produce an electroaeroacoustic system for the active noise control, particularly in a confined flow.

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 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.