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Class Information
Number: 181/206
Name: Acoustics > Sound-modifying means > By wave interference
Description: Subject matter wherein the means for modifying the sound includes modulating the sound by interacting or introducing an additional higher or lower frequency to the sound source, the resulting sound being at a different frequency.

Patents under this class:
1 2 3 4

Patent Number Title Of Patent Date Issued
8712070 Simultaneous enhancement of transmission loss and absorption coefficient using activated cavities Apr. 29, 2014
8613312 Method and apparatus for stimulating wells Dec. 24, 2013
8485309 Apparatus and method for improving the damping of acoustic waves Jul. 16, 2013
8453788 Implementing dynamic noise elimination with acoustic frame design Jun. 4, 2013
8434588 Exhaust device for vehicle internal combustion engine May. 7, 2013
8365861 Muffler unit for fume extractor hood Feb. 5, 2013
8331577 Electronic device having active noise control with an external sensor Dec. 11, 2012
8270628 Method and system for actively influencing noise, and use thereof in a motor vehicle Sep. 18, 2012
8215446 Sound field controller Jul. 10, 2012
8213176 Systems and methods for providing airflow Jul. 3, 2012
8184820 Indirect acoustic transfer control of noise May. 22, 2012
8172036 Apparatus and method for providing acoustic metamaterial May. 8, 2012
8155332 Method and apparatus for attenuating fan noise through turbulence mitigation Apr. 10, 2012
8144889 Noise control system using smart materials Mar. 27, 2012
8122732 Refrigerator with noise reduction structure using inverse phase sound wave Feb. 28, 2012
8116482 Low noise microphone for use in windy environments and/or in the presence of engine noise Feb. 14, 2012
8085944 Device and method for active noise cancellation in an exhaust gas channel of a combustion engine Dec. 27, 2011
8040021 Device for the active damping of the vibrations experienced by a fragile part of moving equipment, with autonomous power supply Oct. 18, 2011
8035966 Electronics package for synthetic jet ejectors Oct. 11, 2011
8005235 Multi-chamber noise control system Aug. 23, 2011
7990701 Computer device with low acoustic noise Aug. 2, 2011
7970148 Simultaneous enhancement of transmission loss and absorption coefficient using activated cavities Jun. 28, 2011
7946383 Acoustic load mitigator May. 24, 2011
7934582 Engine silencing and vibration reduction system and method May. 3, 2011
7929295 Systems and methods for providing airflow Apr. 19, 2011
7896126 Methods and apparatus for sound suppression Mar. 1, 2011
7891463 Active muffler Feb. 22, 2011
7854295 Active noise control system Dec. 21, 2010
7819221 Lightweight acoustic damping treatment Oct. 26, 2010
7800895 Electronic apparatus and sound insulating method thereof Sep. 21, 2010
7775320 Method for reducing noise in a vehicle cabin Aug. 17, 2010
7762373 Fan noise control apparatus Jul. 27, 2010
7753165 Device and method for active noise cancellation in exhaust gas channel of a combustion engine Jul. 13, 2010
7724515 Disk array apparatus May. 25, 2010
7711124 Method and device for attenuating the noise generated at the outlet of an exhaust line May. 4, 2010
7644803 Silencing device Jan. 12, 2010
7631726 Silencer for air induction system and high flow articulated coupling Dec. 15, 2009
7533759 Active muffler for an exhaust system May. 19, 2009
7530426 Device for actively reducing sound transmission, and panel comprising such device May. 12, 2009
7497300 Noise reduction tubes Mar. 3, 2009
7416051 Assembly and method for fan noise reduction from turbofan engines using dynamically adaptive Herschel-Quincke tubes Aug. 26, 2008
7380635 Interference-based exhaust noise attenuation Jun. 3, 2008
7353908 Method and system for attenuating noise from a cabinet housing computer equipment Apr. 8, 2008
7352870 Active sound muffler and active sound muffling method Apr. 1, 2008
7293627 Active exhaust muffler Nov. 13, 2007
7227957 Noise-suppressing receiver Jun. 5, 2007
7077164 Pipe Jul. 18, 2006
6896219 Process and apparatus for noise reduction in multi-engine propeller-driven aircraft May. 24, 2005
6796859 Air intake silencer Sep. 28, 2004
6786037 Segmented mixing device having chevrons for exhaust noise reduction in jet engines Sep. 7, 2004

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