ATE166992T1 - Hybrider aktiver schalldämpfer - Google Patents

Hybrider aktiver schalldämpfer

Info

Publication number
ATE166992T1
ATE166992T1 AT86309564T AT86309564T ATE166992T1 AT E166992 T1 ATE166992 T1 AT E166992T1 AT 86309564 T AT86309564 T AT 86309564T AT 86309564 T AT86309564 T AT 86309564T AT E166992 T1 ATE166992 T1 AT E166992T1
Authority
AT
Austria
Prior art keywords
hybrid active
silencer
duct
active silencer
acoustic wave
Prior art date
Application number
AT86309564T
Other languages
English (en)
Inventor
Mark C Allie
Larry J Eriksson
Richard H Hoops
Original Assignee
Nelson Ind Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nelson Ind Inc filed Critical Nelson Ind Inc
Application granted granted Critical
Publication of ATE166992T1 publication Critical patent/ATE166992T1/de

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N1/00Silencing apparatus characterised by method of silencing
    • F01N1/06Silencing apparatus characterised by method of silencing by using interference effect
    • F01N1/065Silencing apparatus characterised by method of silencing by using interference effect by using an active noise source, e.g. speakers
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10KSOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785Methods, e.g. algorithms; Devices
    • G10K11/17857Geometric disposition, e.g. placement of microphones
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10KSOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785Methods, e.g. algorithms; Devices
    • G10K11/17861Methods, e.g. algorithms; Devices using additional means for damping sound, e.g. using sound absorbing panels
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10KSOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787General system configurations
    • G10K11/17879General system configurations using both a reference signal and an error signal
    • G10K11/17881General system configurations using both a reference signal and an error signal the reference signal being an acoustic signal, e.g. recorded with a microphone
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10KSOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10Applications
    • G10K2210/112Ducts
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10KSOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30Means
    • G10K2210/321Physical
    • G10K2210/3219Geometry of the configuration
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10KSOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30Means
    • G10K2210/321Physical
    • G10K2210/3227Resonators
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10KSOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/50Miscellaneous
    • G10K2210/509Hybrid, i.e. combining different technologies, e.g. passive and active

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Pipe Accessories (AREA)
  • Materials For Photolithography (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)
AT86309564T 1985-12-18 1986-12-09 Hybrider aktiver schalldämpfer ATE166992T1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US06/811,029 US4665549A (en) 1985-12-18 1985-12-18 Hybrid active silencer

Publications (1)

Publication Number Publication Date
ATE166992T1 true ATE166992T1 (de) 1998-06-15

Family

ID=25205347

Family Applications (1)

Application Number Title Priority Date Filing Date
AT86309564T ATE166992T1 (de) 1985-12-18 1986-12-09 Hybrider aktiver schalldämpfer

Country Status (5)

Country Link
US (1) US4665549A (de)
EP (1) EP0227372B1 (de)
AT (1) ATE166992T1 (de)
CA (1) CA1255608A (de)
DE (1) DE3650683T2 (de)

Families Citing this family (103)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5257316A (en) * 1990-10-31 1993-10-26 Matsushita Electric Works, Ltd. Acoustic conductance and silencer utilizing same
US5119427A (en) * 1988-03-14 1992-06-02 Hersh Alan S Extended frequency range Helmholtz resonators
US4815139A (en) * 1988-03-16 1989-03-21 Nelson Industries, Inc. Active acoustic attenuation system for higher order mode non-uniform sound field in a duct
JPH01245795A (ja) * 1988-03-28 1989-09-29 Daikin Ind Ltd 電子消音装置
US4837834A (en) * 1988-05-04 1989-06-06 Nelson Industries, Inc. Active acoustic attenuation system with differential filtering
WO1990004071A1 (en) * 1988-10-12 1990-04-19 Computerswitch Pty Ltd System for modifying acoustic environment
JP2651383B2 (ja) * 1989-03-14 1997-09-10 パイオニア株式会社 指向性を有するスピーカ装置
US5033082A (en) * 1989-07-31 1991-07-16 Nelson Industries, Inc. Communication system with active noise cancellation
US5024288A (en) * 1989-08-10 1991-06-18 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Sound attenuation apparatus
US5044464A (en) * 1990-01-23 1991-09-03 Nelson Industries, Inc. Active acoustic attenuation mixing chamber
US5272286A (en) * 1990-04-09 1993-12-21 Active Noise And Vibration Technologies, Inc. Single cavity automobile muffler
US5133017A (en) * 1990-04-09 1992-07-21 Active Noise And Vibration Technologies, Inc. Noise suppression system
AU7572191A (en) * 1990-04-09 1991-10-30 Active Noise And Vibration Technologies, Inc. Single cavity automobile muffler
US5229556A (en) * 1990-04-25 1993-07-20 Ford Motor Company Internal ported band pass enclosure for sound cancellation
US5323466A (en) * 1990-04-25 1994-06-21 Ford Motor Company Tandem transducer magnet structure
US5119902A (en) * 1990-04-25 1992-06-09 Ford Motor Company Active muffler transducer arrangement
US5319165A (en) * 1990-04-25 1994-06-07 Ford Motor Company Dual bandpass secondary source
DE4027511C1 (de) * 1990-08-30 1991-10-02 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V., 8000 Muenchen, De
US5088575A (en) * 1990-09-13 1992-02-18 Nelson Industries, Inc. Acoustic system with transducer and venturi
US5255321A (en) * 1990-12-05 1993-10-19 Harman International Industries, Inc. Acoustic transducer for automotive noise cancellation
KR930007959B1 (ko) * 1990-12-19 1993-08-25 주식회사 금성사 에어컨디셔너의 소음 저감장치 및 방법
US5511127A (en) * 1991-04-05 1996-04-23 Applied Acoustic Research Active noise control
JPH06508445A (ja) * 1991-04-19 1994-09-22 ノイズ キャンセレーション テクノロジーズ インコーポレーテッド 伝送管路拡声器に関する改良
US5224168A (en) * 1991-05-08 1993-06-29 Sri International Method and apparatus for the active reduction of compression waves
US5283834A (en) * 1991-08-26 1994-02-01 Nelson Industries, Inc. Acoustic system suppressing detection of higher order modes
US5347585A (en) * 1991-09-10 1994-09-13 Calsonic Corporation Sound attenuating system
EP0615648B1 (de) * 1991-12-02 1999-04-21 Noise Cancellation Technologies, Inc. Aktive lärmverminderung in einem gehäuse mit hilfe einer vielzahl von wandlern
US5210805A (en) * 1992-04-06 1993-05-11 Ford Motor Company Transducer flux optimization
US5347586A (en) * 1992-04-28 1994-09-13 Westinghouse Electric Corporation Adaptive system for controlling noise generated by or emanating from a primary noise source
US5822439A (en) * 1992-05-01 1998-10-13 Fujitsu Ten Limited Noise control device
WO1994018923A1 (en) * 1993-02-16 1994-09-01 Noise Cancellation Technologies, Inc. Broad band zonal cancellation in a short duct
US5414775A (en) * 1993-05-26 1995-05-09 Noise Cancellation Technologies, Inc. Noise attenuation system for vibratory feeder bowl
CN1064158C (zh) * 1993-07-07 2001-04-04 莱斯特里兹股份有限公司&废气处理技术公司 有源消声器
US5446249A (en) * 1993-07-13 1995-08-29 Digisonix, Inc. Dry acoustic system preventing condensation
US5494151A (en) * 1993-08-06 1996-02-27 Shinko Electric Co., Ltd. Vibratory parts-feeder apparatus
JP2587683Y2 (ja) * 1993-08-12 1998-12-24 カルソニック株式会社 能動型消音器
US5519637A (en) * 1993-08-20 1996-05-21 Mcdonnell Douglas Corporation Wavenumber-adaptive control of sound radiation from structures using a `virtual` microphone array method
DE4342133A1 (de) * 1993-12-10 1995-06-14 Nokia Deutschland Gmbh Anordnung zur aktiven Schalldämpfung
US6160892A (en) * 1993-12-30 2000-12-12 Bbn Corporation Active muffler
US5660255A (en) * 1994-04-04 1997-08-26 Applied Power, Inc. Stiff actuator active vibration isolation system
US5513266A (en) * 1994-04-29 1996-04-30 Digisonix, Inc. Integral active and passive silencer
US5828768A (en) * 1994-05-11 1998-10-27 Noise Cancellation Technologies, Inc. Multimedia personal computer with active noise reduction and piezo speakers
US5541373A (en) * 1994-09-06 1996-07-30 Digisonix, Inc. Active exhaust silencer
US5693918A (en) * 1994-09-06 1997-12-02 Digisonix, Inc. Active exhaust silencer
FR2740599B1 (fr) 1995-10-30 1997-12-19 Technofirst Dispositif d'attenuation acoustique active destine a etre dispose a l'interieur d'un conduit, en particulier pour l'insonorisation de reseau de ventilation et/ou de climatisation
US5828759A (en) * 1995-11-30 1998-10-27 Siemens Electric Limited System and method for reducing engine noise
JP3654980B2 (ja) * 1995-11-30 2005-06-02 富士通株式会社 能動騒音制御装置及び波形変換装置
US5848168A (en) * 1996-11-04 1998-12-08 Tenneco Automotive Inc. Active noise conditioning system
US5930371A (en) * 1997-01-07 1999-07-27 Nelson Industries, Inc. Tunable acoustic system
US6295363B1 (en) 1997-03-20 2001-09-25 Digisonix, Inc. Adaptive passive acoustic attenuation system
US6084971A (en) * 1997-06-10 2000-07-04 Siemens Electric Limited Active noise attenuation system
DE19832979C1 (de) * 1998-07-22 1999-11-04 Friedmund Nagel Vorrichtung und Verfahren zur Reduzierung der Schallemission bei Verbrennungsmotoren
ATE226684T1 (de) * 1998-07-22 2002-11-15 Friedmund Nagel Vorrichtung und verfahren zur reduzierung der schallemission bei verbrennungsmotoren und zu deren diagnose
US7783055B2 (en) * 1998-07-22 2010-08-24 Silentium Ltd. Soundproof climate controlled rack
US6232994B1 (en) 1998-09-29 2001-05-15 Intermec Ip Corp. Noise cancellation system for a thermal printer
ATE248497T1 (de) * 1999-12-09 2003-09-15 Frederick Johannes Bruwer Sprachsverteilungssystem
US20010046302A1 (en) * 2000-04-14 2001-11-29 Daly Paul D. Active noise cancellation optimized air gaps
US20010046300A1 (en) * 2000-04-17 2001-11-29 Mclean Ian R. Offline active control of automotive noise
US20010036282A1 (en) * 2000-05-12 2001-11-01 Roy Haworth Active noise attenuation inlet microphone system
US6996242B2 (en) * 2000-06-06 2006-02-07 Siemens Vdo Automotive Inc. Integrated and active noise control inlet
US6557665B2 (en) 2000-06-06 2003-05-06 Siemens Canada Limited Active dipole inlet using drone cone speaker driver
AU2001289524A1 (en) * 2000-06-09 2001-12-24 Ziyi Cheng A noise-suppressing receiver
US20020013906A1 (en) * 2000-06-14 2002-01-31 Walter Wallach Secure medical test and result delivery system
FR2812751B1 (fr) * 2000-08-01 2002-11-08 Ecia Equip Composants Ind Auto Dispositif acoustique pour une installation d'attenuation active de bruit
US6775384B2 (en) 2000-09-20 2004-08-10 Siemens Vdo Automotive Inc. Environmentally robust noise attenuation system
US6898289B2 (en) 2000-09-20 2005-05-24 Siemens Vdo Automotive Inc. Integrated active noise attenuation system and fluid reservoir
US20020039422A1 (en) * 2000-09-20 2002-04-04 Daly Paul D. Driving mode for active noise cancellation
US6702061B2 (en) 2001-03-15 2004-03-09 Siemens Vdo Automotive, Inc. Environmentally protected microphone for an active noise control system
US6668970B1 (en) 2001-06-06 2003-12-30 Acoustic Horizons, Inc. Acoustic attenuator
US6684977B2 (en) 2001-09-13 2004-02-03 Siemens Vdo Automotive, Inc. Speaker retention assembly for an active noise control system
WO2003028007A1 (en) * 2001-09-25 2003-04-03 Siemens Vdo Automotive Inc. Modular active noise cancellation air filter speaker and microphone assembly
US7006639B2 (en) * 2001-11-20 2006-02-28 Maximilian Hans Hobelsberger Active noise-attenuating duct element
US20030112981A1 (en) * 2001-12-17 2003-06-19 Siemens Vdo Automotive, Inc. Active noise control with on-line-filtered C modeling
DE10201494A1 (de) * 2002-01-17 2003-07-31 Mann & Hummel Filter Resonator
JP4677744B2 (ja) * 2003-11-04 2011-04-27 ソニー株式会社 噴流発生装置、電子機器及び噴流発生方法
US20070125592A1 (en) * 2005-12-07 2007-06-07 Frank Michell Excitation of air directing valves and air handling surfaces in the cancellation of air handling system noise
US8302456B2 (en) 2006-02-23 2012-11-06 Asylum Research Corporation Active damping of high speed scanning probe microscope components
US7869607B2 (en) 2006-03-02 2011-01-11 Silentium Ltd. Quiet active fan for servers chassis
WO2007099541A2 (en) 2006-03-02 2007-09-07 Silentium Ltd. Quiet active fan for servers chassis
US20110123036A1 (en) * 2006-03-02 2011-05-26 Yossi Barath Muffled rack and methods thereof
EP1993496B1 (de) * 2006-03-02 2020-09-09 Silentium Ltd. Schalldichtes klimagesteuertes gestell
JP4958154B2 (ja) * 2006-11-29 2012-06-20 本田技研工業株式会社 自動二輪車
WO2008090544A2 (en) * 2007-01-22 2008-07-31 Silentium Ltd. Quiet fan incorporating active noise control (anc)
US20080187147A1 (en) * 2007-02-05 2008-08-07 Berner Miranda S Noise reduction systems and methods
DE102007032600A1 (de) * 2007-07-11 2009-01-15 Deutsches Zentrum für Luft- und Raumfahrt e.V. Vorrichtung und Verfahren zur Verbesserung der Dämpfung von akustischen Wellen
DE102008015929A1 (de) * 2008-03-27 2009-10-01 J. Eberspächer GmbH & Co. KG Abgasanlage
US8331577B2 (en) * 2008-07-03 2012-12-11 Hewlett-Packard Development Company, L.P. Electronic device having active noise control with an external sensor
FR2949273B1 (fr) * 2009-08-21 2015-09-25 Christian Carme Barriere acoustique ajouree permettant un traitement hybride passif/actif du bruit
US8452041B2 (en) 2011-03-17 2013-05-28 Eugen Nedelcu Opposing dual-vented woofer system
ES2834442T3 (es) 2011-05-11 2021-06-17 Silentium Ltd Sistema y método de control del ruido
US9928824B2 (en) 2011-05-11 2018-03-27 Silentium Ltd. Apparatus, system and method of controlling noise within a noise-controlled volume
US9508337B2 (en) * 2013-05-17 2016-11-29 Ask Industries Societa Per Azioni Low-noise fume extractor hood
FR3005993B1 (fr) * 2013-05-23 2015-06-26 Dcns Systeme de silencieux actif pour ligne d'echappement d'un moteur diesel notamment de plateforme navale
US9164805B2 (en) * 2013-11-14 2015-10-20 Lenovo Enterprise Solutions (Singapore) Pte. Ltd. Managing workload distribution to reduce acoustic levels
EP2915967B1 (de) * 2014-03-04 2017-08-02 Eberspächer Exhaust Technology GmbH & Co. KG Aktives Design von Auspuffgeräuschen
US9383388B2 (en) 2014-04-21 2016-07-05 Oxford Instruments Asylum Research, Inc Automated atomic force microscope and the operation thereof
FR3023645B1 (fr) * 2014-07-10 2020-02-28 Centre National De La Recherche Scientifique Dispositif et methode d'attenuation du son
KR20170097153A (ko) 2014-12-19 2017-08-25 제네럴 일렉트릭 컴퍼니 능동 소음 제어 시스템
US10839302B2 (en) 2015-11-24 2020-11-17 The Research Foundation For The State University Of New York Approximate value iteration with complex returns by bounding
JP2017141976A (ja) * 2016-02-08 2017-08-17 パナソニックIpマネジメント株式会社 送風装置
WO2017183999A1 (en) 2016-04-20 2017-10-26 General Electric Company Active noise cancelation systems and devices
EP3242292A1 (de) 2016-05-04 2017-11-08 Sontech International AB Schalldämpfungsvorrichtung
DE102017200822A1 (de) * 2017-01-19 2018-07-19 Bayerische Motoren Werke Aktiengesellschaft Belüftungseinrichtung für einen Innenraum eines Kraftwagens und Verfahren zum Betrieb einer solchen Belüftungseinrichtung

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2983790A (en) * 1953-04-30 1961-05-09 Rca Corp Electronic sound absorber
US3936606A (en) * 1971-12-07 1976-02-03 Wanke Ronald L Acoustic abatement method and apparatus
US4025724A (en) * 1975-08-12 1977-05-24 Westinghouse Electric Corporation Noise cancellation apparatus
GB1583758A (en) * 1976-10-01 1981-02-04 Nat Res Dev Attenuation of sound waves in ducts
US4122303A (en) * 1976-12-10 1978-10-24 Sound Attenuators Limited Improvements in and relating to active sound attenuation
EP0040613B1 (de) * 1979-11-21 1986-02-05 Sound Attenuators Limited Verbessertes verfahren und apparat zum dämpfen der vibration
US4473906A (en) * 1980-12-05 1984-09-25 Lord Corporation Active acoustic attenuator
ZA825676B (en) * 1981-08-11 1983-06-29 Sound Attenuators Ltd Method and apparatus for low frequency active attennuation

Also Published As

Publication number Publication date
DE3650683D1 (de) 1998-07-09
EP0227372A2 (de) 1987-07-01
EP0227372B1 (de) 1998-06-03
EP0227372A3 (de) 1988-01-07
US4665549A (en) 1987-05-12
DE3650683T2 (de) 1999-02-25
CA1255608A (en) 1989-06-13

Similar Documents

Publication Publication Date Title
ATE166992T1 (de) Hybrider aktiver schalldämpfer
GB2088951B (en) Acoustic attenuators with active sound cancelling
EP0333461A3 (en) Active acoustic attenuation system for higher order mode non-uniform sound field in a duct
GB949503A (en) Noise attenuating method and apparatus
ATE135130T1 (de) Kopfhörer
DK440983A (da) Lyddaempningsorganer til stoevsuger
ES2134645T3 (es) Dispositivo de atenuacion acustica activa para ser colocado dentro de un conducto, en especial para insonorizar una red de ventilacion y/o climatizacion.
PT806922E (pt) Almofada de auscultador
CZ132299A3 (cs) Zařízení na absorbování a/nebo tlumení zvukových vln
MY125747A (en) Speaker system
AU3534378A (en) Room reverberation and noise cancelling system
MX9300120A (es) Sistema mejorado de distribucion de audio.
Eriksson et al. Higher order mode cancellation in ducts using active noise
ES449356A1 (es) Perfeccionamientos en sistemas amplificadores para redes te-lefonicas.
DE69913726D1 (de) Lautsprecher mit phasenunkorrelierter diffuser schallquelle
FR2329929A1 (fr) Dispositifs absorbeurs acoustiques actifs pour des conduits
ES2160639T3 (es) Dispositivo de composicion de numeros telefonicos.
CA2124183A1 (en) Active Noise Control of an Enclosure with Multiple Transducers
CA2188534A1 (en) Active Noise Cancelling Muffler
FR2307330A1 (fr) Attenuateur acoustique, inserable notamment dans un conduit d'air
SE0003350D0 (sv) Ljuddämpare
SE8406282D0 (sv) Ljuddempare for reducering av kanalburet luftljud
Sha et al. An active sound absorber in ducts
JPS5229213A (en) Fire retardant speaker diaphragm
HASSAN Analysis of combustion generated noise[Final Technical Report, May 1974- Dec. 1976]