Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Muller-bbm Gmbh

Müller-bbm Active Sound Technology Gmbh

Roland Lippold

Helmut V Fuchs

Philip Leistner

Jan Krueger

Rolf Schirmacher

Florian Walter

Fabian Evert

Method for influencing noise, wherein a noise source (), in particular an engine in a motor vehicle, generates the noise with a substantially periodically variable excitation, and wherein a reference variable which is characteristic of the noise source, in particular an engine speed, is present at predetermined successive supply instants (t), comprising the method steps; reading out at least a first value (N) of the reference variable at a first supply instant (t) and a second predetermined value at a second supply instant (t); generating the reference signal () at at least one instant (t) between the second supply instant (t) and a third supply instant (t) as a function of the first and second values that were read out; and sending the reference signal () to a device for actively influencing noise (), which generates activation signals () for at least one actuator () as a function of the reference signal (), wherein the at least one actuator () emits compensation sound, which interferes with the noise.

Method and system for actively influencing noise, and use thereof in a motor vehicle

A reactive sound attenuator which includes a sensor for detecting a sound parameter in a space, e.g. a duct, consists of a signal amplifier that is used to amplify a detected signal, an electroacoustic transducer and a cavity with at least one membrane. The membrane, which is capable of moving in a vibratory manner, is part of a wall of a space, e.g. a duct wall. A sensor, which is disposed in the immediate vicinity of, in or on the membrane, detects the vibrations of the membrane. The sensor's signal, which is amplified and inverted by the amplifier, controls the membrane vibration via the electroacoustic transducer.

Reactive sound absorber

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Dresden, Germany

Roland Lippold