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

Inventio Ag

Philip Leistner

Helmut V Fuchs

Jan Krueger

Karlheinz Bay

Michael Leistner

Daniel Beer

Lutz Ehrig

Lorenz Betz

Alex Oberer

Yvan Kurzo

Xueqin Zha

Roland Lippold

Gerhard Babuke

Horst Drotleff

Klaus Sedlbauer

Klaus Breuer

Waldemar Maysenhölder

Mark Koehler

Xiaoru Zhou

Andreas Liebl

An acoustic system is provided that includes a transducer having a housing, which encloses a volume and in which at least a surface or a sub-surface is formed by a sheet-like structure configured to vibrate. Powder made of adsorbent material having an adsorption effective surface may be present in the volume. The powder may be selected such that, through a movement of the powder caused by vibrations of the sheet-like structure configured to vibrate, the adsorption effective surface is enlarged. The adsorbent material may be selected such that an adsorption of air or gas present in the volume is caused by an increase of the pressure caused from vibrations of the sheet-like structure configured to vibrate. The powder is freely movable within the housing.

Acoustic system having a housing with adsorbent powder

An electroacoustic driver includes a diaphragm, a diaphragm drive system and a diaphragm suspension. The diaphragm system is configured to subject the diaphragm to a motion, wherein the diaphragm suspension is configured to guide the diaphragm. The diaphragm drive system includes an active element configured to actively influence the motion of the diaphragm.

Electroacoustic driver

The invention relates to a controlled acoustic wave guide configured as an elongated hollow chamber () which via an opening () in its first face end () is connected to a sound-conducting channel (). The longitudinal resonances of the hollow chamber () can be adjusted to a sound spectrum to be dampened. To this end diaphragm vibrations are detected by means of a microphone () which is positioned directly in front of the diaphragm () of at least one loud-speaker () at the second face-end () of the hollow chamber (). The microphone signal is then inverted using an amplifier () and fed back to the loud-speaker () after amplification in accordance with a sensor () signal characterizing the sound spectrum in the channel ().

Controlled acoustic waveguide for soundproofing

Structured pre-form bodies as panel lining for wide-band sound absorption are made of an open-cell foam material having a rigid framework co-vibrating in a resonant manner at low frequencies. The pre-form bodies have a base layer and a columnar structure positioned directly in front of or on the base layer. The columnar structure has a non-symmetrical distribution of height and cross-section, thereby forming a wide-band tuned moderator gap and the columnar height corresponds approximately to the density of the base layer. The columnar structure has a framework resonance adjustable as a function of parameters of the base layer.

Structured molded parts for sound absorption

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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Stuttgart, Germany

Philip Leistner