Loudspeaker with passive low frequency directional control
US8428284B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 2010 |
| Grant date | Apr 23, 2013 |
| Priority date | — |
| Expiry date | Apr 1, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R1/288
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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 loudspeaker 11 has a transducer 13, an enclosure 21 behind the transducer, and port openings 29 in the sidewalls 23 of 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 material 33 in the acoustic chamber 27 formed behind the transducer 13 by the enclosure 21. A fibrous material is selected having a low-pass transfer function and low acoustic loss in its low-frequency pass band.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.