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:
Apr. 23, 2013
Filed:
Mar. 19, 2010
John D. Meyer, Berkeley, CA (US);
Jean Pierre Mamin, La Tour de Peilz, CH;
Pablo Espinosa, Pleasanton, CA (US);
Peter Kowalczyk, Berkeley, CA (US);
John D. Meyer, Berkeley, CA (US);
Jean Pierre Mamin, La Tour de Peilz, CH;
Pablo Espinosa, Pleasanton, CA (US);
Peter Kowalczyk, Berkeley, CA (US);
Meyer Sound Laboratories, Incorporated, Berkeley, CA (US);
Abstract
A loudspeaker is provided that passively achieves a directional polar response at low frequencies with a high degree of attenuation between the front and the back of the loudspeaker. The loudspeakerhas a transducer, an enclosurebehind the transducer, and port openingsin the sidewallsof the enclosure to allow a back-wave produced by the transducer to exit the enclosure and combine with the front wave produced by the transducer. Cancellation behind the loudspeaker at low frequencies is achieved by delaying the back wave with low loss. Low loss delay at low frequencies is achieved by inserting a low-density fibrous fill materialin the acoustic chamberformed behind the transducerby the enclosure. A fibrous material is selected having a low-pass transfer function and low acoustic loss in its low-frequency pass band.