WO2001047320A1 - Haut-parleurs - Google Patents

Haut-parleurs Download PDF

Info

Publication number
WO2001047320A1
WO2001047320A1 PCT/GB2000/004655 GB0004655W WO0147320A1 WO 2001047320 A1 WO2001047320 A1 WO 2001047320A1 GB 0004655 W GB0004655 W GB 0004655W WO 0147320 A1 WO0147320 A1 WO 0147320A1
Authority
WO
WIPO (PCT)
Prior art keywords
acoustic
loudspeaker according
radiator
filter means
pattern
Prior art date
Application number
PCT/GB2000/004655
Other languages
English (en)
Inventor
Neil Harris
Original Assignee
New Transducers Limited
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 New Transducers Limited filed Critical New Transducers Limited
Priority to AU17201/01A priority Critical patent/AU1720101A/en
Priority to GB0209536A priority patent/GB2371941A/en
Publication of WO2001047320A1 publication Critical patent/WO2001047320A1/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
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/045—Plane diaphragms using the distributed mode principle, i.e. whereby the acoustic radiation is emanated from uniformly distributed free bending wave vibration induced in a stiff panel and not from pistonic motion

Definitions

  • the invention relates to loudspeakers. More particularly, but not exclusively, the invention relates to resonant panel -form loudspeakers generally of the kind disclosed in International patent application WO97/09842 of New Transducers Ltd. BACKGROUND ART
  • loudspeaker uses resonant bending wave modes excited by an exciter to produce output sound and may be referred to as a distributed mode loudspeaker.
  • Such resonant panel -form loudspeakers may comprise a member having capability to sustain and propagate input vibrational energy by bending waves m at least one operative area extending transversely of thickness to have resonant mode vibration components distributed over said at least one area and have preferential locations or sites within said area for transducer means and having an exciter mounted on said member at one of said locations or sites to vibrate the member to cause it to resonant forming an acoustic radiator.
  • the invention is loudspeaker comprising an acoustic radiator capable of supporting bending waves, an exciter mounted on the acoustic radiator to excite bending waves in the acoustic radiator to produce an acoustic output and filter means located adjacent to the acoustic radiator for directing the acoustic output from the acoustic radiator, said filter means adapted to have a pattern of varying acoustic absorbency, the pattern being selected to produce a desired directivity of the acoustic output.
  • the filter means may be m the form of an acoustic mask comprising a pattern of at least one acoustic aperture.
  • the desired directivity may be achieved by purely mechano-acoustic means, without associated electronic components or signal processing.
  • a resonant bending wave mode loudspeaker having an acoustic radiator and an exciter fixed to the acoustic radiator for exciting resonant bending wave modes.
  • a loudspeaker is described in WO97/09842 and other patent applications and publications and may be referred to as a distributed mode loudspeaker.
  • the acoustic radiator may be m the form of a panel .
  • the panel may be flat and may be lightweight.
  • the material of the acoustic radiator may be amsotropic or lsotropic.
  • the acoustic mask is preferably of a material which does not propagate the acoustic output from the radiator, i.e. the mask is preferably acoustically opaque and non- resonant .
  • the acoustic mask may be co-extensive with the resonant panel.
  • the acoustic mask is preferably not directly connected to the panel, to prevent direct transmission of acoustic energy from the panel to the mask.
  • the distance between the mask and the panel is preferably as small as possible and is preferably significantly less than the shortest acoustic wavelength in the operating frequency range.
  • the acoustic radiator is preferably of the kind described International application WO97/09842.
  • the properties of the acoustic radiator may be chosen to distribute the resonant bending wave modes, particularly the lower frequency resonant bending wave modes, substantially evenly in frequency.
  • the lower frequency resonant bending wave modes are preferably the ten to twenty lowest frequency resonant bending wave modes of the acoustic radiator.
  • the resonant bending wave modes associated with each conceptual axis of the acoustic radiator may be arranged to be interleaved frequency. There may be two conceptual axes and the axes may be symme ry axes .
  • the transducer location may be chosen to couple substantially evenly to the resonant bending wave modes. In particular, the transducer location may be chosen to couple substantially evenly to lower frequency resonant bending wave modes.
  • the transducer may be at a location where the number of vibrationally active resonance anti- nodes is relatively high and conversely the number of resonance nodes is relatively low.
  • the pattern of acoustic apertures is a function of the desired . ar-field directivity and may be determined so as ootentially to produce any desired directivity P x . In practice an arbitrary and complex transmission index for the filter means may not be easy to produce.
  • the or each acoustic aperture may be of arbitrary shape.
  • the or each acoustic apertures may be the form of a hole or a slots.
  • the width of a hole is similar to its height, whereas the width of a slot is large compared to its height.
  • the pattern of acoustic apertures may be a binary function wherein the value 1 represents a hole or a slot and the value 0 denotes no transmission. Obviously, it is impossible to realise an acoustic aperture which is outside the range [0,1] passively.
  • variable damping may be provided as a way of controlling directivity from a resonant panel loudspeaker.
  • the filter means may be m the form a plate of contoured acoustic foam giving position dependent absorption.
  • This method for calculating the position and/or shape of the hole(s) and slot (s) is similar to focal-plane processing which is used the field of optics.
  • Focal- plane processing uses the fact that an optical lens produces at its focus, a spatial Fourier transform of the source. The transformed image is selectively obscured by a pattern of slots, holes, rings etc., effecting a spatial filter. The image is formed using a second lens to invert the Fourier transform. It is possible that the source is virtual, whereby an illuminated shadow mask (or hologram) is focused to produce a pre-calculated image. Thus a combination of lenses and shadow masks are used to process images. These systems work best in monochromatic light .
  • One advantage that optics has over acoustics is the relatively narrow bandwidth that is required. White light covers less than one octave of wavelengths, whereas the acoustic equivalent can cover up to three decades.
  • the method may be used in conjunction with standard optimisation techniques to give desired levels of optimality over specified frequency ranges.
  • the opacity of the mask may not be absolute, i.e. the mask strength may be between 0 and 1 (or even complex) . Optimisation may then be applied and may produce a different solution to the binary case.
  • Figure 2 is a side view of a second embodiment 1-D according to the invention.
  • Figure 3 is a plot of the directivity of the unfiltered resonant panel loudspeaker of Figure 2.
  • Figure 4 is a plot of the directivity of the resonant panel loudspeaker of Figure 2 filtered according to the invention.
  • FIG. 1 shows an acoustic radiator (10) in the form of a resonant panel and substantially co-extensive filter means (12) located m front of and adjacent to the radiator (10) for directing acoustic output from the radiator (10) , said filter means (12) being m the form of an acoustic mask comprising four acoustic apertures.
  • the pattern (11) of acoustic apertures s determined so as to produce the desired directivity of acoustic output.
  • the pattern of acoustic apertures consists of three holes ( 14 ) and one s lot ( 16 ) .
  • the acoustic mask (12) is not directly connected to the panel (10) .
  • Figure 2 shows an acoustic radiator (28) in the form of a 1-D resonant panel and substantially co-extensive filter means (30) located in front of and adjacent to the radiator (28) for directing acoustic output from the radiator (28) , said filter means (30) being m the form of an acoustic mask comprising two acoustic apertures (31,32) .
  • the position and width of acoustic apertures (31,32) is determined so as to produce the desired directivity of acoustic output.
  • the acoustic mask (A) is calculated from a simple function
  • A(a,b,c, ⁇ ) (
  • the values of a, b and c are then calculated to give the desired directivity Pj by minimising the error between the desired directivity and the calculated directivity using the least mean squared relationship.
  • Figure 3 shows the normal, i.e. unfiltered directivity of the resonant panel of Figure 2 at three frequencies, namely 300Hz (18), 1kHz (20) and 3kHz (22). At 300 Hz, the acoustic output is uniformly distributed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
  • Transducers For Ultrasonic Waves (AREA)

Abstract

L"invention concerne un haut-parleur ayant un radiateur acoustique (10) pouvant supporter des ondes de flexion, un excitateur monté sur le radiateur acoustique (10, 28) servant à exciter les ondes de flexion dans le radiateur acoustique (10, 28) afin de produire une sortie acoustique, et des éléments filtre (12, 30) adjacents au radiateur acoustique (10, 28) et servant à diriger ladite sortie acoustique en provenance du radiateur acoustique (10, 28). Les éléments filtre (12, 30) peuvent avoir un motif (11) d"absorption acoustique variable, ce motif (11) étant sélectionné en vue de produire une directivité recherchée de la sortie acoustique. Les éléments filtre (12, 30) peuvent se présenter sous forme d"un masque acoustique comprenant un motif (11) avec au moins une ouverture acoustique (14, 16).
PCT/GB2000/004655 1999-12-21 2000-12-06 Haut-parleurs WO2001047320A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU17201/01A AU1720101A (en) 1999-12-21 2000-12-06 Loudspeakers
GB0209536A GB2371941A (en) 1999-12-21 2000-12-06 Loudspeakers

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9930275.4A GB9930275D0 (en) 1999-12-21 1999-12-21 Loudspeakers
GB9930275.4 1999-12-21

Publications (1)

Publication Number Publication Date
WO2001047320A1 true WO2001047320A1 (fr) 2001-06-28

Family

ID=10866801

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2000/004655 WO2001047320A1 (fr) 1999-12-21 2000-12-06 Haut-parleurs

Country Status (4)

Country Link
AU (1) AU1720101A (fr)
GB (2) GB9930275D0 (fr)
TW (1) TW494702B (fr)
WO (1) WO2001047320A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002045460A2 (fr) * 2000-11-30 2002-06-06 New Transducers Limited Hauts-parleurs
US6839444B2 (en) 2000-11-30 2005-01-04 New Transducers Limited Loudspeakers

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862366A (en) * 1971-08-16 1975-01-21 Elektroakusztikai Gyar Sound radiation system
US5297214A (en) * 1988-09-19 1994-03-22 Bruney Paul F Loudspeaker structure
US5668886A (en) * 1993-03-30 1997-09-16 Kabushiki Kaisha Kenwood Loudspeaker structure
WO1999002012A1 (fr) * 1997-07-03 1999-01-14 New Transducers Limited Haut-parleurs en forme de panneaux
WO1999011490A1 (fr) * 1997-09-03 1999-03-11 New Transducers Limited Panneau de garniture avec systeme acoustique integre
WO1999012387A1 (fr) * 1997-09-04 1999-03-11 New Transducers Limited Haut-parleur
EP0924960A2 (fr) * 1997-12-20 1999-06-23 NOKIA TECHNOLOGY GmbH Suspension pour des arrangements de reproduction sonore selon le principe des ondes de flexion

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862366A (en) * 1971-08-16 1975-01-21 Elektroakusztikai Gyar Sound radiation system
US5297214A (en) * 1988-09-19 1994-03-22 Bruney Paul F Loudspeaker structure
US5668886A (en) * 1993-03-30 1997-09-16 Kabushiki Kaisha Kenwood Loudspeaker structure
WO1999002012A1 (fr) * 1997-07-03 1999-01-14 New Transducers Limited Haut-parleurs en forme de panneaux
WO1999011490A1 (fr) * 1997-09-03 1999-03-11 New Transducers Limited Panneau de garniture avec systeme acoustique integre
WO1999012387A1 (fr) * 1997-09-04 1999-03-11 New Transducers Limited Haut-parleur
EP0924960A2 (fr) * 1997-12-20 1999-06-23 NOKIA TECHNOLOGY GmbH Suspension pour des arrangements de reproduction sonore selon le principe des ondes de flexion

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002045460A2 (fr) * 2000-11-30 2002-06-06 New Transducers Limited Hauts-parleurs
WO2002045460A3 (fr) * 2000-11-30 2003-03-13 New Transducers Ltd Hauts-parleurs
US6839444B2 (en) 2000-11-30 2005-01-04 New Transducers Limited Loudspeakers

Also Published As

Publication number Publication date
AU1720101A (en) 2001-07-03
GB9930275D0 (en) 2000-02-09
TW494702B (en) 2002-07-11
GB0209536D0 (en) 2002-06-05
GB2371941A (en) 2002-08-07

Similar Documents

Publication Publication Date Title
US8891782B2 (en) Apparatus and method for sound focusing
EP1110426B1 (fr) Dispositif acoustique en forme de panneau utilisant des modes a ondes de flexion
EP1070437B1 (fr) Dispositif acoustique
AU2016210715B2 (en) Acoustic Diffusion Generator
WO2000002417A1 (fr) Haut-parleur se presentant sous forme de panneau resonnant
JPH11220789A (ja) 電気音響変換装置
SK25398A3 (en) Acoustic device
EA002097B1 (ru) Громкоговоритель со звукоизлучающей панелью, излучающим элементом
US6553124B2 (en) Acoustic device
US6694038B1 (en) Acoustic device
US20010005421A1 (en) Loudspeakers
WO2001047320A1 (fr) Haut-parleurs
US6298140B1 (en) Electroacoustic transducer with improved tonal quality
JP2009147951A (ja) スピーカシステム及びスピーカクラスターシステム
US6675932B2 (en) Speaker housing configured to minimize standing waves and resonate above the frequency range of transducers
US6334505B1 (en) Optimum edges for speakers and musical instruments
RU2018207C1 (ru) Способ озвучивания закрытых помещений и открытых пространств
Shen et al. Sound radiation from building elements
RU2237981C2 (ru) Способ излучения звуковых сигналов во внешнее пространство и акустическая система
Wodtke et al. Quieting Plate Modes With Optimally Sized Point Masses: A Volume Velocity Approach
CN117998259A (zh) 扬声器
MXPA01002270A (en) Panel form acoustic apparatus using bending waves modes
JPH0638284A (ja) 位相反転式スピーカ装置
MXPA01004508A (es) Altavoz que comprende una fuente de sonido difusa no correlacionada con la fase

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
ENP Entry into the national phase

Ref country code: GB

Ref document number: 200209536

Kind code of ref document: A

Format of ref document f/p: F

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP