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WO1992019080A1 - Perfectionnements apportes aux haut-parleurs a ligne de transmission - Google Patents

Perfectionnements apportes aux haut-parleurs a ligne de transmission Download PDF

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Publication number
WO1992019080A1
WO1992019080A1 PCT/US1991/002731 US9102731W WO9219080A1 WO 1992019080 A1 WO1992019080 A1 WO 1992019080A1 US 9102731 W US9102731 W US 9102731W WO 9219080 A1 WO9219080 A1 WO 9219080A1
Authority
WO
WIPO (PCT)
Prior art keywords
drain
back chamber
chamber
loudspeaker
transmission line
Prior art date
Application number
PCT/US1991/002731
Other languages
English (en)
Inventor
Khosrow Eghtesadi
William John Joseph Hoge
Original Assignee
Noise Cancellation Technologies, 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 Noise Cancellation Technologies, Inc. filed Critical Noise Cancellation Technologies, Inc.
Priority to HK98112067.6A priority Critical patent/HK1011163B/en
Priority to JP3518527A priority patent/JPH06508445A/ja
Priority to DE69129664T priority patent/DE69129664T2/de
Priority to DK91920600T priority patent/DK0580579T3/da
Priority to CA002108696A priority patent/CA2108696A1/fr
Priority to EP91920600A priority patent/EP0580579B1/fr
Priority to ES91920600T priority patent/ES2118093T3/es
Priority to PCT/US1991/002731 priority patent/WO1992019080A1/fr
Publication of WO1992019080A1 publication Critical patent/WO1992019080A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
    • H04R1/2807—Enclosures comprising vibrating or resonating arrangements
    • H04R1/2838—Enclosures comprising vibrating or resonating arrangements of the bandpass type
    • H04R1/2842—Enclosures comprising vibrating or resonating arrangements of the bandpass type for loudspeaker transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/30—Combinations of transducers with horns, e.g. with mechanical matching means, i.e. front-loaded horns

Definitions

  • This invention relates to a method of and apparatus for improving the performance of transmission line loudspeakers and has particular applications in active noise control, high fidelity audio, and sound reinforcement systems.
  • the simplest form of a loudspeaker system is the direct radiator.
  • a loudspeaker radiates sound directly form the enclosure aperture(s) ⁇ the driver diaphragm and, in the case of vented-box systems, a vent or port. There are no additional devices through which the sound passes.
  • a transmission line loudspeaker adds an additional device, such as a horn for impedance matching, through which some or all of the sound passes.
  • Prior forms of transmission line systems may be divided into three classes.
  • a type A transmission line system consists of a closed-box direct radiator loudspeaker with a transmission line added to the driver aperture. All radiated sound passes through the transmission line.
  • a Type B or C system consists of a direct radiator system with the transmission line coupled to the back chamber of the enclosure. Both the Type B or Type C form exhibit the fault that the transmission line presents an acoustical short circuit to the back of the driver at least at some frequencies. This can cause serious dips in the system response.
  • This invention relates to an improved form of the Type A System in which the signals from both the drive aperture and the port of a vented-box direct radiator system are combined to drive the transmission line.
  • the original form of the Type A system prevents the back wave from the drive diaphragm from interfering with the front wave by trapping the back wave in the closed cavity behind the driver.
  • the improved system passes the back wave trough an acoustic phase inverter so that it may be combined with the output from the front side of the driver. This doubles the energy available to drive the transmission line. This improvement should not be confused with hybrid systems which used a vented-box system with the transmission line coupled to either the driver aperture or the vent but not both.
  • the improved performance is roughly analogous to that seen in a vented-box direct radiator system as compared to a closed- box system. Either the efficiency or the bandwidth may be increased; or the system size may be decreased; or a tradeoff may be made among these possible benefits.
  • one or more electrodynamic loudspeaker drivers is installed in a vented-box direct radiator enclosure, and a cover is added to the front of the enclosure.
  • This cover forms a front chamber into which both the driver and the vent radiate sound. The sound passes through the front chamber and into the transmission line.
  • the transmission line should be a horn.
  • a compact system might use a short tube. Such a tube is too short to exhibit transmission line characteristics. It will act as lumped parameter acoustic mass instead.
  • the transmission characteristics of the improved system using a horn will be determined in great measure by the horn and the acoustic load it presents to the front chamber, but will, in general, be high-pass in nature.
  • the transmission characteristics of the short tube system will be band-pass in nature, the driver and the vented-box portion of the enclosure will provide a 4-pole high-pass response, and the front chamber and the outlet tube will provide a 2-pole low-pass response.
  • Another arrangement of the apparatus according to the present invention is particularly useful for active noise cancellation applications such as exhaust mufflers or duct silencers. In this arrangement the pipe or duct through which the noisy signal is flowing passes through the enclosure and exists through the outlet tube.
  • the end of the noisy pipe or duct is aligned with the end of the loudspeaker and the two are coaxial.
  • the antinoise signal radiated by the loudspeaker during the active cancellation is coaxial with the noise.
  • Very good cancellation may be obtained at frequencies with wavelenghts which are long compared to the size of the outlet.
  • FIGS. 1 and 3 are signal flow graphs of the improved loudspeaker with a long transmission line and a short outlet tube
  • FIGS. 2 and 4 are simplfied drawings of the invention, and FIGS. 5 to 9 show two ways in which the invention may be put to practical use in noise cancellation applications.
  • FIG. 10 shows a general form of a vented box bandpass loudspeaker.
  • FIG. 11 shows a simplified acoustical analagous circuit.
  • FIG. 2 shows an electrodynamic loudspeaker driver 1 mounted in an enclosure 2 so that one side of the driver diaphragm radiates sound into the fornt chamber of the enclosure 3.
  • the sound form the other side of the driver passes through the acoustic phase inverter comprising the back chamber 4 and the inner vent 5 which connects the front and back chambers.
  • the total system output consists of the sum of the front wave and the phase corrected back wave flowing through the front chamber and out via the transmission line 6.
  • FIG. 1 shows the basic signal flow graph of the system using an electroydnamic driver 1.
  • Electric potential E g is applied accross the driver voice coil which has a resistance R E and a resulting current I VC flows.
  • the electrodynamic coupling Bl of the motor causes a driving force.
  • the sum of this force and the various reaction forces in the system gives in the total force driving the diaphragm F D .
  • This force accelerates the diaphrgam at a rate inversely proportional to the moving mass M MS of the driver.
  • the resulting acceleration of the diaphragm a D is integrated once with respect to time (the 1/s operation in the LaPlace domain) to find the velocity of the diaphragm u D and a second time to find the displacement of the diaphragm x D .
  • moving the diaphragm results in some reaction forces.
  • an opposing force inversely proportional to the mechanical compliance C MS of the driver is added to the total force F D .
  • Another opposing force results from the motion through the mechanical losses R MS of the system and is equal to the product of R MS and u D .
  • the front side pushes against the surrounding air and a flow into the front chamber 3 results.
  • This volume U D is equal to the product of the diaphragam velocity u D and its effective area S D .
  • This volume velocity is one of the components of the total flow into the from chamber U F .
  • the conservation of matter requires that the flow into the back chamber U B across the boundary between it and the front chamber be equal to U F but opposite in polarity.
  • the volume velocity U B presurizes the back chamber 4.
  • the acoustic pressure of the back chamber p B is equal to the integral of U B with respect to time divided by the acoustic compliance to the back chamber C AB . This pressure exerts another reaction force against the back of the diaphragm which is equal to the pressure p B times the diaphragm area S D .
  • This another component of F D is another component of F D .
  • the analysis of the system is similar, except that the line impedance is simplifed because the short tube presents a lumped parameter element.
  • the output flow U O is equal to the front chamber pressure p F integrated with respect to time and divided by the acoustic mass of the outlet vent M AF .
  • the opposing pressure component of p F results from the flow losses in the outlet R AF .
  • FIGS. 5 to 8 show views of a practical loudspeaker system using the present invention which has particular application in active noise control systems.
  • a flow tube 7 for the noisy flow (such as the exhaust of an engine)
  • a drain tube 8 has been added between the front and back chamber so that water or other liquids trapped in the back chamber may escape. If the loudspeaker were used in an active noise cancellation system on a vehicle and if the vehicle were driven through deep water, the muffler could be flooded. The drain tube would allow the trapped water to flow out of the back chamber.
  • the drain tube must be sized so that it acts as an acoustic mass rather than an acoustic leak between the chambers. Its mass must either be considered when adjusting the enclosure tuning or be trivial compared to the inner vent 5 so that the effect of the drain may be ignored.
  • FIG. 9 shows an apparatus using the present invention which also has particular application for active noise control.
  • the short tube 6 is formed by the area between the heat shield plate 7 and the connection to the noisy duct 8.
  • a long, narrow tube 9 allows outsider air to enter the enclosure.
  • This tube like the drain tube discussed above, should be sized so that it has no adverse effect on the system acoustic performance. It may enter the enclosure through either the front or back chamber. Air is forced through the system because of the venturi-like detail 10 in the noisy duct. The flow through the duct over the "venturi” cause a low pressure region which "draws" the outside air. This air may be useful for cooling or removal of corrosive gases.
  • VBBP Vented Box Bandpass Loudspeaker
  • Fig. 11 shows the simplified acoustical analagous circuit of the Vented Box Bandpass Loudspeaker (VBBP) configuration.
  • the terms R o and P g are determined by the following formulal:
  • Equation (1) Substitute Equations (4) and (6) into the Equation (1)

Landscapes

  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Circuit For Audible Band Transducer (AREA)

Abstract

L'onde acoustique émise à partir de la face avant (UF) de la membrane amplificatrice d'un haut-parleur présente une polarité opposée à celle de l'onde émise à partir de la face arrière (UB). Si l'on associe les signaux directement l'un à l'autre, ils auront tendance à se neutraliser. On utilise un réseau inverseur de phase acoustique (5) pour s'assurer que l'onde arrière est en phase avec l'onde avant, et l'on utilise les signaux associés pour commander l'entrée d'une ligne de transmission (6) de haut-parleur.
PCT/US1991/002731 1991-04-19 1991-04-19 Perfectionnements apportes aux haut-parleurs a ligne de transmission WO1992019080A1 (fr)

Priority Applications (8)

Application Number Priority Date Filing Date Title
HK98112067.6A HK1011163B (en) 1991-04-19 Noise control apparatus
JP3518527A JPH06508445A (ja) 1991-04-19 1991-04-19 伝送管路拡声器に関する改良
DE69129664T DE69129664T2 (de) 1991-04-19 1991-04-19 Vorrichtung zur geräuschunterdrückung
DK91920600T DK0580579T3 (da) 1991-04-19 1991-04-19 Støjkontrolapparat
CA002108696A CA2108696A1 (fr) 1991-04-19 1991-04-19 Ameliorations pour enceintes acoustiques a labyrinthe
EP91920600A EP0580579B1 (fr) 1991-04-19 1991-04-19 Dispositif de suppression de bruit
ES91920600T ES2118093T3 (es) 1991-04-19 1991-04-19 Aparato de control del ruido.
PCT/US1991/002731 WO1992019080A1 (fr) 1991-04-19 1991-04-19 Perfectionnements apportes aux haut-parleurs a ligne de transmission

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA002108696A CA2108696A1 (fr) 1991-04-19 1991-04-19 Ameliorations pour enceintes acoustiques a labyrinthe
PCT/US1991/002731 WO1992019080A1 (fr) 1991-04-19 1991-04-19 Perfectionnements apportes aux haut-parleurs a ligne de transmission

Publications (1)

Publication Number Publication Date
WO1992019080A1 true WO1992019080A1 (fr) 1992-10-29

Family

ID=25676762

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/002731 WO1992019080A1 (fr) 1991-04-19 1991-04-19 Perfectionnements apportes aux haut-parleurs a ligne de transmission

Country Status (7)

Country Link
EP (1) EP0580579B1 (fr)
JP (1) JPH06508445A (fr)
CA (1) CA2108696A1 (fr)
DE (1) DE69129664T2 (fr)
DK (1) DK0580579T3 (fr)
ES (1) ES2118093T3 (fr)
WO (1) WO1992019080A1 (fr)

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0828466A4 (fr) * 1994-05-10 1998-03-18
EP1323332A4 (fr) * 2000-10-06 2006-01-25 Logitech Europ Sa Enceinte acoustique a chambre double
EP1994793A4 (fr) * 2006-03-15 2011-11-02 Thomas J Danley Reproduction sonore avec caracteristiques en basse frequence ameliorees
EP2581567A1 (fr) * 2011-10-14 2013-04-17 J. Eberspächer GmbH & Co. KG Silencieux actif
US9564146B2 (en) 2014-08-01 2017-02-07 Bongiovi Acoustics Llc System and method for digital signal processing in deep diving environment
US9615813B2 (en) 2014-04-16 2017-04-11 Bongiovi Acoustics Llc. Device for wide-band auscultation
US9621994B1 (en) 2015-11-16 2017-04-11 Bongiovi Acoustics Llc Surface acoustic transducer
US9638672B2 (en) 2015-03-06 2017-05-02 Bongiovi Acoustics Llc System and method for acquiring acoustic information from a resonating body
US9741355B2 (en) 2013-06-12 2017-08-22 Bongiovi Acoustics Llc System and method for narrow bandwidth digital signal processing
US9793872B2 (en) 2006-02-07 2017-10-17 Bongiovi Acoustics Llc System and method for digital signal processing
EP3162084A4 (fr) * 2014-06-26 2017-12-13 Bisset, Anthony Allen Système compact de haut-parleur à pavillon de graves et médial à large bande
US9883318B2 (en) 2013-06-12 2018-01-30 Bongiovi Acoustics Llc System and method for stereo field enhancement in two-channel audio systems
US9906858B2 (en) 2013-10-22 2018-02-27 Bongiovi Acoustics Llc System and method for digital signal processing
US9906867B2 (en) 2015-11-16 2018-02-27 Bongiovi Acoustics Llc Surface acoustic transducer
US10069471B2 (en) 2006-02-07 2018-09-04 Bongiovi Acoustics Llc System and method for digital signal processing
US10158337B2 (en) 2004-08-10 2018-12-18 Bongiovi Acoustics Llc System and method for digital signal processing
US10639000B2 (en) 2014-04-16 2020-05-05 Bongiovi Acoustics Llc Device for wide-band auscultation
US10701505B2 (en) 2006-02-07 2020-06-30 Bongiovi Acoustics Llc. System, method, and apparatus for generating and digitally processing a head related audio transfer function
US10820883B2 (en) 2014-04-16 2020-11-03 Bongiovi Acoustics Llc Noise reduction assembly for auscultation of a body
US10848118B2 (en) 2004-08-10 2020-11-24 Bongiovi Acoustics Llc System and method for digital signal processing
US10848867B2 (en) 2006-02-07 2020-11-24 Bongiovi Acoustics Llc System and method for digital signal processing
US10959035B2 (en) 2018-08-02 2021-03-23 Bongiovi Acoustics Llc System, method, and apparatus for generating and digitally processing a head related audio transfer function
CN113504663A (zh) * 2021-07-23 2021-10-15 歌尔光学科技有限公司 发声模组、发声模组的消声方法和智能眼镜
US11202161B2 (en) 2006-02-07 2021-12-14 Bongiovi Acoustics Llc System, method, and apparatus for generating and digitally processing a head related audio transfer function
US11211043B2 (en) 2018-04-11 2021-12-28 Bongiovi Acoustics Llc Audio enhanced hearing protection system
US11431312B2 (en) 2004-08-10 2022-08-30 Bongiovi Acoustics Llc System and method for digital signal processing

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US4549631A (en) * 1983-10-24 1985-10-29 Bose Corporation Multiple porting loudspeaker systems
US4616731A (en) * 1984-03-02 1986-10-14 Robinson James R Speaker system
US4875546A (en) * 1988-06-02 1989-10-24 Teledyne Industries, Inc. Loudspeaker with acoustic band-pass filter
US5025885A (en) * 1989-07-14 1991-06-25 Bose Corporation Multiple chamber loudspeaker system

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JPS5789393A (en) * 1980-11-17 1982-06-03 Bose Corp Controller for low end response for loudspeaker system
US4473906A (en) * 1980-12-05 1984-09-25 Lord Corporation Active acoustic attenuator
US4665549A (en) * 1985-12-18 1987-05-12 Nelson Industries Inc. Hybrid active silencer
JPH0787628B2 (ja) * 1989-02-22 1995-09-20 株式会社ケンウッド 低音再生用スピーカシステム
JP4862491B2 (ja) * 2005-05-25 2012-01-25 東レ株式会社 植毛用パイルおよび植毛製品

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US4549631A (en) * 1983-10-24 1985-10-29 Bose Corporation Multiple porting loudspeaker systems
US4616731A (en) * 1984-03-02 1986-10-14 Robinson James R Speaker system
US4875546A (en) * 1988-06-02 1989-10-24 Teledyne Industries, Inc. Loudspeaker with acoustic band-pass filter
US5025885A (en) * 1989-07-14 1991-06-25 Bose Corporation Multiple chamber loudspeaker system

Non-Patent Citations (1)

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Title
See also references of EP0580579A4 *

Cited By (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0828466A4 (fr) * 1994-05-10 1998-03-18
EP1323332A4 (fr) * 2000-10-06 2006-01-25 Logitech Europ Sa Enceinte acoustique a chambre double
US11431312B2 (en) 2004-08-10 2022-08-30 Bongiovi Acoustics Llc System and method for digital signal processing
US10666216B2 (en) 2004-08-10 2020-05-26 Bongiovi Acoustics Llc System and method for digital signal processing
US10158337B2 (en) 2004-08-10 2018-12-18 Bongiovi Acoustics Llc System and method for digital signal processing
US10848118B2 (en) 2004-08-10 2020-11-24 Bongiovi Acoustics Llc System and method for digital signal processing
US10069471B2 (en) 2006-02-07 2018-09-04 Bongiovi Acoustics Llc System and method for digital signal processing
US10848867B2 (en) 2006-02-07 2020-11-24 Bongiovi Acoustics Llc System and method for digital signal processing
US11425499B2 (en) 2006-02-07 2022-08-23 Bongiovi Acoustics Llc System and method for digital signal processing
US11202161B2 (en) 2006-02-07 2021-12-14 Bongiovi Acoustics Llc System, method, and apparatus for generating and digitally processing a head related audio transfer function
US10701505B2 (en) 2006-02-07 2020-06-30 Bongiovi Acoustics Llc. System, method, and apparatus for generating and digitally processing a head related audio transfer function
US9793872B2 (en) 2006-02-07 2017-10-17 Bongiovi Acoustics Llc System and method for digital signal processing
EP1994793A4 (fr) * 2006-03-15 2011-11-02 Thomas J Danley Reproduction sonore avec caracteristiques en basse frequence ameliorees
US9206717B2 (en) 2011-10-14 2015-12-08 Eberspaecher Exhaust Technology Gmbh & Co. Kg Active sound absorbers
CN103114889A (zh) * 2011-10-14 2013-05-22 J·埃贝斯佩歇合资公司 有源消声器
EP2581567A1 (fr) * 2011-10-14 2013-04-17 J. Eberspächer GmbH & Co. KG Silencieux actif
US9883318B2 (en) 2013-06-12 2018-01-30 Bongiovi Acoustics Llc System and method for stereo field enhancement in two-channel audio systems
US9741355B2 (en) 2013-06-12 2017-08-22 Bongiovi Acoustics Llc System and method for narrow bandwidth digital signal processing
US10999695B2 (en) 2013-06-12 2021-05-04 Bongiovi Acoustics Llc System and method for stereo field enhancement in two channel audio systems
US10412533B2 (en) 2013-06-12 2019-09-10 Bongiovi Acoustics Llc System and method for stereo field enhancement in two-channel audio systems
US10917722B2 (en) 2013-10-22 2021-02-09 Bongiovi Acoustics, Llc System and method for digital signal processing
US10313791B2 (en) 2013-10-22 2019-06-04 Bongiovi Acoustics Llc System and method for digital signal processing
US9906858B2 (en) 2013-10-22 2018-02-27 Bongiovi Acoustics Llc System and method for digital signal processing
US11418881B2 (en) 2013-10-22 2022-08-16 Bongiovi Acoustics Llc System and method for digital signal processing
US11284854B2 (en) 2014-04-16 2022-03-29 Bongiovi Acoustics Llc Noise reduction assembly for auscultation of a body
US10820883B2 (en) 2014-04-16 2020-11-03 Bongiovi Acoustics Llc Noise reduction assembly for auscultation of a body
US9615813B2 (en) 2014-04-16 2017-04-11 Bongiovi Acoustics Llc. Device for wide-band auscultation
US10639000B2 (en) 2014-04-16 2020-05-05 Bongiovi Acoustics Llc Device for wide-band auscultation
EP3162084A4 (fr) * 2014-06-26 2017-12-13 Bisset, Anthony Allen Système compact de haut-parleur à pavillon de graves et médial à large bande
US9564146B2 (en) 2014-08-01 2017-02-07 Bongiovi Acoustics Llc System and method for digital signal processing in deep diving environment
US9638672B2 (en) 2015-03-06 2017-05-02 Bongiovi Acoustics Llc System and method for acquiring acoustic information from a resonating body
US9621994B1 (en) 2015-11-16 2017-04-11 Bongiovi Acoustics Llc Surface acoustic transducer
US9906867B2 (en) 2015-11-16 2018-02-27 Bongiovi Acoustics Llc Surface acoustic transducer
US9998832B2 (en) 2015-11-16 2018-06-12 Bongiovi Acoustics Llc Surface acoustic transducer
US11211043B2 (en) 2018-04-11 2021-12-28 Bongiovi Acoustics Llc Audio enhanced hearing protection system
US12175960B2 (en) 2018-04-11 2024-12-24 Bongiovi Acoustic Llc Audio enhanced hearing protection system
US10959035B2 (en) 2018-08-02 2021-03-23 Bongiovi Acoustics Llc System, method, and apparatus for generating and digitally processing a head related audio transfer function
CN113504663A (zh) * 2021-07-23 2021-10-15 歌尔光学科技有限公司 发声模组、发声模组的消声方法和智能眼镜

Also Published As

Publication number Publication date
EP0580579A1 (fr) 1994-02-02
DE69129664D1 (de) 1998-07-30
CA2108696A1 (fr) 1992-10-20
DE69129664T2 (de) 1998-12-03
HK1011163A1 (en) 1999-07-02
EP0580579A4 (en) 1994-06-15
EP0580579B1 (fr) 1998-06-24
ES2118093T3 (es) 1998-09-16
DK0580579T3 (da) 1999-04-06
JPH06508445A (ja) 1994-09-22

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