WO1999045742A1 - Haut parleur a friction acoustique pour amortissement de resonance - Google Patents

Haut parleur a friction acoustique pour amortissement de resonance Download PDF

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Publication number
WO1999045742A1
WO1999045742A1 PCT/IB1999/000242 IB9900242W WO9945742A1 WO 1999045742 A1 WO1999045742 A1 WO 1999045742A1 IB 9900242 W IB9900242 W IB 9900242W WO 9945742 A1 WO9945742 A1 WO 9945742A1
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WO
WIPO (PCT)
Prior art keywords
housing
loudspeaker
damping means
configuration
duct
Prior art date
Application number
PCT/IB1999/000242
Other languages
English (en)
Inventor
Erich Klein
Original Assignee
Koninklijke Philips Electronics N.V.
Philips Ab
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 Koninklijke Philips Electronics N.V., Philips Ab filed Critical Koninklijke Philips Electronics N.V.
Publication of WO1999045742A1 publication Critical patent/WO1999045742A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details

Definitions

  • the invention relates to a loudspeaker configuration for radiating sound into an acoustic free space, comprising an electrodynamic loudspeaker and a housing which accommodates the loudspeaker and which isolates the loudspeaker at its back in an acoustically impermeable manner with respect to the free space, and damping means accommodated in the housing and providing an acoustic friction, by which damping means the sound pressure rise, caused by the housing, at the basic loudspeaker resonant frequency which has been shifted by the housing is damped.
  • Such a loudspeaker configuration of the type defined in the opening paragraph is commercially available in different versions and is consequently known.
  • the known loudspeaker configuration uses for example wadding, cellular plastics or similar damping materials as damping means inside the housing.
  • damping means must be fitted separately in the housing of such a loudspeaker configuration during the manufacture of the loudspeaker configuration, which is an additional operation and, moreover, such damping means lead to additional costs, which make the loudspeaker configuration more expensive.
  • damping means are merely capable of damping the sound pressure rise caused by the housing at the basic loudspeaker resonant frequency which is shifted by the housing.
  • the damping means are formed by at least one duct which provides an acoustic friction, and the at least one duct is realized with the aid of a part of the housing and an associated part of the loudspeaker configuration, which associated part adjoins the part of the housing.
  • the at least one duct provided as damping means can be formed between a part of the housing and an associated part of a magnet system of the electrodynamic loudspeaker.
  • the measures defined in the dependent Claim 2 are taken.
  • Such a construction has the advantage that it can be manufactured easily.
  • each duct serving as a damping means can be manufactured with a high accuracy, as a result of which the friction realized by means of such a duct is within comparatively narrow tolerance limits and, consequently, a highly controlled damping of the sound pressure rise caused by the housing at the basic loudspeaker resonant frequency which is shifted by the housing can be achieved.
  • a loudspeaker configuration in accordance with the invention having the characteristic features defined in the dependent Claim 1 it has further proved to be very advantageous if, in addition, the measures defined in the dependent Claim 3 are taken. This is advantageous for simple production, particularly if the housing, i.e. the two housing sections, are made of a plastic and are manufactured in an injection-molding process.
  • the housing may alternatively comprise more than two housing sections, in which case at least one duct, which acts as a damping means for the sound pressure rise caused by the housing at the basic loudspeaker resonant frequency which is shifted by the housing, can be provided between every two housing sections.
  • Figure 1 shows, partly in diagrammatic form, a loudspeaker configuration having a housing comprising two housing sections by means of which ducts acting as damping means have been realized.
  • Figure 2 is a diagram which represents the sound pressure that can be generated by the loudspeaker of the loudspeaker configuration of Figure 1 in dependence on the frequency under different conditions.
  • FIG. 1 shows a loudspeaker configuration 1.
  • the loudspeaker configuration 1 serves for the emission of sound into a acoustic free space 2.
  • the loudspeaker configuration 1 includes an electrodynamic loudspeaker 3 and has a housing 4.
  • the electrodynamic loudspeaker 3 has a plastic supporting member 5 which is constructed to support a magnet system 6 and to support a diaphragm 7 and a centering ring 8.
  • the magnetic system 6 comprises a permanent magnet 9, which is disposed between a discshaped yoke member 10 and an annular yoke member 11.
  • a cylindrical yoke member 12 is integral with the disc-shaped yoke member 10 and its end portion 13 is surrounded by the annular yoke member 11 , an annular air gap being formed between the cylindrical yoke member 12 and the annular yoke member 11.
  • a moving coil 14 is arranged in the air gap and is connected to the diaphragm 7 of the loudspeaker 3 in a manner not shown in Figure 1.
  • connection between the moving coil 14 and the diaphragm 7 can be made, for example, by means of an adhesive joint and, moreover, in the area of the connection between the moving coil 14 and the diaphragm 7 a connection to the centering ring 8 is formed, which is realized by ultrasonic spot-welding and the additional application of an adhesive.
  • the diaphragm 7 is connected to the supporting member 5 by means of an adhesive joint.
  • the centering ring 8 is also connected to the supporting member 5 by means of an adhesive joint.
  • the moving coil 14 is connected to two contact terminals, of which only one contact terminal 18 is visible in Figure 1, via two connecting wires which extend behind the diaphragm 7, of which also only one connecting wire 17 is visible in Figure 1.
  • the housing 4 of the loudspeaker configuration 1 comprises two housing sections 19 and 20.
  • the first housing section 19 is substantially pot-shaped and 4 thus has a bottom wall 21 and a hollow cylindrical circumferential wall 22, while in addition an annular end wall 23 is connected to the hollow cylindrical circumferential wall 22.
  • the first housing section 19 has a stepped portion 24 in which the supporting member 5 is fitted, the supporting member 5 being fixed in the stepped portion 24 by means of an adhesive joint.
  • the second housing section 20 is also substantially pot-shaped and thus has a bottom wall 25 and a circumferential wall 26.
  • the first housing section 19 is placed onto the second housing section 20 with its end wall 23.
  • the bounding wall 23 may be connected to the circumferential wall 26 in the area of the free end 27 of the circumferential wall 26.
  • the curve referenced 28 relates to the variation of the sound pressure produced by the loudspeaker 3 when the loudspeaker 3 without its housing 4 is mounted in an infinitely large baffle. This curve shows that the basic resonant frequency fi of the loudspeaker 3 lies at approximately 250 Hz and that a slight sound pressure rise of approximately 77 dB occurs at this basic loudspeaker resonant frequency fi .
  • the curve referenced 29 relates to the variation of the sound pressure produced by the loudspeaker 3 when the loudspeaker 3 is built into a housing which corresponds to the housing 4 of the loudspeaker configuration 1 but which does not have damping means for damping a resonance rise.
  • This curve 29 shows that in this case the basic loudspeaker resonant frequency f 2 of the loudspeaker 3 lies at approximately 450 Hz and that a distinct sound pressure rise of approximately 83 dB occurs at this basic loudspeaker resonant frequency f 2 .
  • the loudspeaker configuration 1 shown in Figure 1 has been provided with damping means 30 comprised in the housing 4 and providing an acoustic 5 friction, which damping means damp the sound pressure rise, caused by the housing 4, at the basic loudspeaker resonant frequency f shifted by the housing 4 during operation of the loudspeaker configuration 1.
  • the damping means 30 are advantageously formed by a plurality of ducts which each form an acoustic friction, two of said ducts 31 and 32 being shown in Figure 1, as will be described in detail hereinafter.
  • Each of the ducts 31 and 32 are shown in Figure 1, as will be described in detail hereinafter.
  • the afore-mentioned part of the housing 4 is formed by the bottom wall 21 of the first housing section 19.
  • the afore-mentioned associated part of the loudspeaker configuration 1 is formed by an annular and, consequently, hollow cylindrical intermediate wall 33 of the second housing section 20, which wall 33 projects from the bottom wall 25 of the second housing section 20 towards the loudspeaker 3.
  • the bottom wall 21 of the first housing section 19 has an opening so that the bottom wall 21 of the first housing section 19 is, in fact, annular.
  • the hollow cylindrical intermediate wall 33 of the second housing section 20 projects through the opening in the bottom wall 21.
  • a press-fit is formed between the bottom wall 21 and the intermediate wall 33 and, consequently, the cylindrical bounding surface 34 of the annular bottom wall 21 fits snugly against the cylindrical bounding surface 35 of the intermediate wall
  • a plurality of grooves have been formed at the location of the bounding surface 35 of the intermediate wall 33 of the second housing section 20, of which only two grooves 36 and 37 are shown in bold lines in Figure 1.
  • Each of these grooves 36 and 37 forms with the bounding surface 34 of the bottom wall 21 of the first housing section 19 a duct which acts as a damping means, i.e. also the two ducts 31 and 32 visible in Figure 1.
  • the grooves 36 and 37 i.e. the ducts 31 and 32, locally interrupt the inherently acoustically impermeable connection between the bottom wall 21 and the intermediate wall 33, which is advantageously utilized for damping purposes.
  • the sound pressure rise, caused by the housing 4, at the basic loudspeaker resonant frequency f 2 which has been shifted by the housing 4, which frequency is 6 450 Hz in the present case, during operation of the loudspeaker configuration 1, is damped clearly, as is apparent from the curve 38 representing the variation of the sound pressure produced by the loudspeaker 3, when the loudspeaker 3 has been mounted in the housing 4 provided with the damping means 30, i.e. with the ducts 31 and 32.
  • the damping thus obtained results in a sound pressure of substantially 77 dB at the shifted basic loudspeaker resonant frequency f 2 .
  • the loudspeaker configuration 1 shown in Figure 1 has the advantage that it does not require any separate means for realizing an acoustic friction for damping the sound pressure rise, caused by the housing 4, at the basic loudspeaker resonant frequency f 2 which has been shifted by the housing 4.
  • the damping means 30 for damping said sound pressure rise have been realized by means of the two housing sections 19 and 20, which is advantageous for a very simple and low-cost construction.
  • the provision of damping means 30 realized by means of the ducts 31 and 32 have the advantage that a rise in sound pressure at higher frequencies around 1500 Hz is obtained, which neither requires any separate means.
  • the invention is not limited to the embodiment described hereinbefore by way of example.
  • a construction can be used in which similarly, but as a variant to the loudspeaker configuration 1 shown in Figure 1, the bottom wall 21 of the first housing section 19 cooperates with the supporting member 5, in which case the supporting member extends through an opening in the bottom wall 21 of the first housing section 19, which bottom wall is again annular, and is formed with grooves at the location of the bounding surface 34 of the bottom wall 21, which grooves in conjunction with the cylindrical bounding surface of the supporting member each form a duct which provides acoustic friction, so that all these ducts again act as damping means for damping the sound pressure rise, caused by the housing 4, at the basic loudspeaker resonant frequency f 2 which has been shifted by the housing 4.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)

Abstract

La présente invention concerne une configuration de haut-parleur (1) comprenant un haut-parleur électrodynamique (3), une enceinte (4), et un dispositif d'amortissement (30) servant à amortir l'augmentation de la pression acoustique provoquée par l'enceinte (4), à la fréquence de résonance de base f2 du haut parleur qui a été décalée par l'enceinte (4). Le dispositif d'amortissement (30) est formé par au moins un conduit (31, 32) et fournit une friction acoustique, chaque conduit (31, 32) étant réalisé à l'aide d'une partie (21) de l'enceinte (4) et d'une partie associée (33) de la configuration du haut-parleur (1), dont la partie associée (33) jouxte la partie (21) de l'enceinte (4).
PCT/IB1999/000242 1998-03-03 1999-02-11 Haut parleur a friction acoustique pour amortissement de resonance WO1999045742A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP98890054.4 1998-03-03
EP98890054 1998-03-03

Publications (1)

Publication Number Publication Date
WO1999045742A1 true WO1999045742A1 (fr) 1999-09-10

Family

ID=8237150

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB1999/000242 WO1999045742A1 (fr) 1998-03-03 1999-02-11 Haut parleur a friction acoustique pour amortissement de resonance

Country Status (1)

Country Link
WO (1) WO1999045742A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9107003B2 (en) 2011-12-15 2015-08-11 Apple Inc. Extended duct with damping for improved speaker performance
US10299032B2 (en) 2017-09-11 2019-05-21 Apple Inc. Front port resonator for a speaker assembly
US11451902B1 (en) 2021-05-07 2022-09-20 Apple Inc. Speaker with vented resonator
US11490190B1 (en) 2021-05-07 2022-11-01 Apple Inc. Speaker with multiple resonators

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3790724A (en) * 1971-04-14 1974-02-05 Philips Corp Electromagnetic microphone including at least one acoustic resistance
JPS6184992A (ja) * 1984-10-02 1986-04-30 Matsushita Electric Ind Co Ltd スピ−カ
US4618025A (en) * 1980-09-15 1986-10-21 Sherman Dan R Acoustical ducting for speakers and enclosures
EP0453230A2 (fr) * 1990-04-20 1991-10-23 Matsushita Electric Industrial Co., Ltd. Système de haut-parleur
DE29515842U1 (de) * 1994-11-17 1995-12-07 Philips Electronics Nv Elektroakustischer Wandler mit einer Durchsteckreibung

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3790724A (en) * 1971-04-14 1974-02-05 Philips Corp Electromagnetic microphone including at least one acoustic resistance
US4618025A (en) * 1980-09-15 1986-10-21 Sherman Dan R Acoustical ducting for speakers and enclosures
JPS6184992A (ja) * 1984-10-02 1986-04-30 Matsushita Electric Ind Co Ltd スピ−カ
EP0453230A2 (fr) * 1990-04-20 1991-10-23 Matsushita Electric Industrial Co., Ltd. Système de haut-parleur
DE29515842U1 (de) * 1994-11-17 1995-12-07 Philips Electronics Nv Elektroakustischer Wandler mit einer Durchsteckreibung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Vol. 7, No. 107, (E-174); & JP 58029297 A (MATSUSHITA DENKI SANGYO K.K.) 21 February 1983. *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9107003B2 (en) 2011-12-15 2015-08-11 Apple Inc. Extended duct with damping for improved speaker performance
US10299032B2 (en) 2017-09-11 2019-05-21 Apple Inc. Front port resonator for a speaker assembly
US11451902B1 (en) 2021-05-07 2022-09-20 Apple Inc. Speaker with vented resonator
US11490190B1 (en) 2021-05-07 2022-11-01 Apple Inc. Speaker with multiple resonators

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