The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 07, 1999
Filed:
Mar. 02, 1998
Volker Bartels, Hannover, DE;
Burkhard Markmann, Seelze, DE;
Sennheiser electronic KG, Wedemark, DE;
Abstract
A sound reproduction device such as a headphone with active noise compensation has a housing and a transducer for converting electrical signals to sound waves is disposed within the housing. The transducer has a diaphragm for separating the volume (V.sub.2) in front of the diaphragm from the volume (V.sub.1) to the rear of the diaphragm. The transducer diaphragm and rear volume (V.sub.1) have a determined compliance. The sound reproduction device includes active noise compensation components for reducing unwanted noise at the output of the transducer. The diaphragm has a compliance (N.sub.M) which is less than the compliance (N.sub.1) of the rear volume (V.sub.1). The diaphragm is preferably constructed from a plurality of layers. In a further preferred arrangement, a damping element is disposed very close to the rear side of the diaphragm. A preferred construction for optimizing the voice coil is described. In an active noise compensation construction employing a microphone having a central axis for picking up noise, a preferred arrangement orients the central microphone axis at an angle of about 45.degree. relative to the central axis of the transducer.