GB1592246A - Creation of Inventions and Patents with Artificial Intelligence

GB1592246A – Sound projection system
– Google Patents

GB1592246A – Sound projection system
– Google Patents
Sound projection system

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Info

Publication number
GB1592246A

GB1592246A
GB39603/76A
GB3960376A
GB1592246A
GB 1592246 A
GB1592246 A
GB 1592246A
GB 39603/76 A
GB39603/76 A
GB 39603/76A
GB 3960376 A
GB3960376 A
GB 3960376A
GB 1592246 A
GB1592246 A
GB 1592246A
Authority
GB
United Kingdom
Prior art keywords
projection system
sound projection
channel
loudspeaker
housing
Prior art date
1976-09-23
Legal status (The legal status 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 status listed.)

Expired

Application number
GB39603/76A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)

Individual

Original Assignee
Individual
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.)
1976-09-23
Filing date
1976-09-23
Publication date
1981-07-01

1976-09-23
Application filed by Individual
filed
Critical
Individual

1976-09-23
Priority to GB39603/76A
priority
Critical
patent/GB1592246A/en

1977-09-14
Priority to CA286,716A
priority
patent/CA1076033A/en

1977-09-16
Priority to US05/833,873
priority
patent/US4181193A/en

1977-09-22
Priority to DE19772742600
priority
patent/DE2742600A1/en

1977-09-22
Priority to JP52113424A
priority
patent/JPS6057759B2/en

1977-09-22
Priority to AU29023/77A
priority
patent/AU515535B2/en

1981-07-01
Publication of GB1592246A
publication
Critical
patent/GB1592246A/en

1983-08-02
Priority to US06/519,752
priority
patent/USRE32183E/en

Status
Expired
legal-status
Critical
Current

Links

Espacenet

Global Dossier

Discuss

239000006185
dispersion
Substances

0.000
claims
description
2

230000005855
radiation
Effects

0.000
claims
description
2

239000000463
material
Substances

0.000
description
4

238000013016
damping
Methods

0.000
description
2

230000002745
absorbent
Effects

0.000
description
1

239000002250
absorbent
Substances

0.000
description
1

238000006243
chemical reaction
Methods

0.000
description
1

238000006073
displacement reaction
Methods

0.000
description
1

239000000428
dust
Substances

0.000
description
1

238000004519
manufacturing process
Methods

0.000
description
1

238000000034
method
Methods

0.000
description
1

239000011120
plywood
Substances

0.000
description
1

239000007787
solid
Substances

0.000
description
1

239000002023
wood
Substances

0.000
description
1

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

H04R1/30—Combinations of transducers with horns, e.g. with mechanical matching means, i.e. front-loaded horns

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

H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only

H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means

Description

PATENT SPECIFICATION ( 11) 1 592 246
9; ( 21) Application No 39603/76 ( 22) Filed 23 Sep 1976 ( 19) ( 23) Complete Specification Filed 12 Sep 1977 ( 44) Complete Specification Published 1 Jul 1981 ( 51) INT CL 3 H 04 R 1/30 l/ ( 52) Index at Acceptance H 4 X 3 C 3 G H 4 J 30 F 31 H B ( 54) SOUND PROJECTION SYSTEM (” 1 \Tmr, trows’, PATENTS ACT 1949 SPECIFICATI ON NO 1592246 The following amendments were allowed under Section 29 on October 1985 Page 1 Line 61 Page 3 Line 58 After diaphragm insert the rear portion being spaced away from the cone diaphragm by a distance substantially greater than the maximum longitudinal displacement of the cone diaphragm in response to an electrical signal.
Page 2 Line b 7 Delete 28 insert 30 THE PATENT OFFICE 9 December 1985 ERRATUM SPECIFICATION NO 1592246
Page No 2 Line No 122 after approximately delete 2 ” insert 12 ” Page No 2 Line No 128 after the (first occurrence) delete face insert fact THE PATENT OFFICE 17 December 1985 4 member detining a single longitudinally of the channel is governed Dy fine cross Yu PATENT SPECIFICATION ( 11) 1 592 246 Application No 39603/76 ( 22) Filed 23 Sep 1976 Complete Specification Filed 12 Sep 1977 ( 44) Complete Specification Published 1 Jul 1981 ( 51) INT CL 3 HO 4 R 1/,30 ( 52) Index at Acceptance H 4 X 3 C 3 G H 4 J 3 OF 31 H B ( 54) SOUND PROJECTION SYSTEM ( 71) 1, TIMOTHY PETER ISAAC, a British subject, of 2 Priory Road, Needingworth, Huntingdon, Cambridgeshire, (previously of 41 Lonsdale Road, Barnes, London SW 13 9 JR), do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:This invention relates to a sound projection system One application of the invention is to a sound projection system which is particularly suitable for use outdoors, and in other environments where it is necessary to transmit sound over relatively long distancs, in the form of a fairly narrow beam.
A large number of special tvpes of transducers, and enclosures for transducers have been proposed, which variously aiim to provide improved directional characteristics, efficiency, and/or band width of response, and one of the more successful types of system is the well known horn-loaded type In this type of system, the transducer feeds into the rear of a flared horn, the characteristics of which are such that very efficient conversion of electrical energy into acoustic energy can be obtained, as compared to a loudspeaker without such adorn.
Such horns do however suffer from a number of disadvantages in practice, fi that in most cases they need to be rather large and of special shape so that they are difficult to fabricate; and furthermore they are not easily adaptable for different environments, since the ideal shape for the horn varies with the environment, e g the size of room, in which it is being used.
Further such horns are not as directional as may be desired in some instances.
According to the invention there is provided a sound projection system comprising a housing and a longitudinally extending member defining a single longitudinally extending acoustic channel which is acoustically open at a front end of the channel and acoustically closed at a rear end and at sides of the channel, and a loudspeaker having a cone diaphragm operating into the channel at the rear end of the channel, the longitudinally extending member being located directly in front of, and with its longitudinal axis in alignment with the radiation axis of, the loudspeaker, the member having a front portion, which is tapered towards the front of the channel, and a rear portion which is tapered more abruptly than the front portion towards the loudspeaker and projects into the part frusto-conical volume defined by the cone diaphragm.
Preferably the loudspeaker is mounted in an aperture in a baffle board, the channel extending forwardly of the baffle board.
Preferably the baffle board is at the front of an enclosure Preferably the enclosure is a sealed enclosure.
The enclosure and the housing may’ be formed as a single cabinet.
The housing may be externally parallel sided along its length.
The member may have a rounded rear end facing the loudspeaker Preferably, however, the member has a flat rear enrd facing the loudspeaker.
A mounting for the member may be adapted to receive a range of such members of various lengths, cross sections and profiles so that the system may be adapted to various working conditions by providing different sound dispersion characteristics.
The member may be divided along its length into two or more separable sections so that the member of a chosen length, cross-section profile, and front and rear termination configuration can be assembled from a set of components.
Because the effective internal crosssectional area at any place along the length of the channel is governed by the cross( 21) ( 23) ( 1 C ell ( 19) So 1 592 246 sectional area of the member at that place, it is relatively easy to form a “horn” type of system using this arrangement Members of various cross-sections and profiles can be simply turned out of wood or other suitable materials, so as to provide almost any desired variations of the effective crosssectional area of the horn along its length.
Clearly, to manufacture a housing with complex variations of cross-sectional area along its length would be very much more complicated.
Two embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a longitudinal cross-section through a sound projection system forming a first embodiment of the invention; Figure 2 is an end view of the system of Figure 1 seen from the open end of the channel; Figure 3 is a cross-section through a sound projection system forming a second embodiment of the invention; and Figure 4 is a fragmentary perspective view of the system of Figure 3.
The system shown in Figures 1 and 2 comprises a cabinet of square cross-section, which is constructed as rigidly as possible from a material which is substantially “dead” acoustically, such as solid timber A loudspeaker enclosure 4 at the rear end of the cabinet is provided with a baffle board 6 facing the front end 8 of the cabinet which is open, and the baffle board has an aperture in which a loudspeaker having a cone diaphragm is mounted The joints of the enclosure 4 and the joint between the loudspeaker and the baffle board are made airtight so as to provide a “totally enclosed” type of enclosure of fixed and relatively small volume behind the speaker The enclosure 4 is preferably filled with acoustically absorbent material to provide internal damping in known manner per se.
The part of the cabinet in front of the speaker is a housing 12, with parallel plane outer surfaces, and is provided with triangular fillets 14 extending along the inside edges of the housing The fillets are in the form of isosceles triangles, each one having its base 16 in contact with, and extending across one corner of the baffle board 6; and having its apex 18 adjacent the corresponding corner of the open end 8 of the housing The housing 12 thus defines a longitudinally extending acoustic channel which is acoustically open at the front end thereof (that is, to the right in Figure 1) but is otherwise acoustically closed, more particularly at the rear end and at the sides of the acoustic channel, the loudspeaker operating into the rear end of the channel The fillets 14 provide the housing 12 with an inernal cross-sectional area which varies along the axis of the housing 12.
A restrictor member 20 is axially mounted in the housing 12 so as to extend into the aperture 10 of the baffle board with its rear end 22 close to the voice coil assembly 24 of the loudspeaker The front end 26 of the restrictor member 20 extends to the region of the front aperture 8 of the housing.
The restrictor member 20 is generally bullet or “stream-line” shaped, having a maximum cross-sectional area in its central region and tapering towards both ends, more rapidly to the rear than the front For different applications, it may be found desirable to use a restrictor member of a different central profile, or having differently profiled end portions, and the restrictor member of this embodiment may therefore be formed in four sections 28, 30, 32 and 34 in Figure 1 In this case only one of these, that is section 28 in the drawings, is fixedly mounted to the cabinet 2 by means of a pair of radially extending fins 36 and the other sections are provided with screw threaded connections by means of which they may be attached to each other and to the fixed section 30.
In order to ensure the smoothest possible sound wave travel along the housing, the mounting fins 36 are preferably of streamlined section, their cross-section corresponding to that of the restrictor member, but on a reduced scale.
A prototype system which has been found to have excellent characteristics compared with an ordinary horn-loaded system, being noticeably lacking in the forms of intermodulation distortion commonly produced by horns, and which manifests itself as a quality of “throatiness” in speech, has been built to the following dimensions:
Overall length of cabinet 12: 2 ‘ 6 ” Aperture at open end 8:12 ” square Length of enclosure 4: 9 ” Length of restrictor means 20: 22 ” Diameter of restrictor means 20 at widest point: 5 ” Diameter of restrictor half way between widest point and front end: 4 ” Restrictor mounting fins 36, length along housing: 51 Spacing between rear end of restrictor means and loudspeaker voice coil dust cap:
The loudspeaker used in this system was approximately 2 ” ( 12 inches) in overall diameter The system was constructed from a” thick plywood It is believed that at least some of the improved characteristics of the system, as compared to an ordinary horn, result from the face that the transducer and the enclosure are more readily “coupled” by the arrangement of the restrictor member.
1 30) 1 592 246 The system illustrated in Figures 3 and 4 is similar in many respects to the system of Figures 1 and 2, and corresponding references are accordingly used in Figures 3 and 4, but with the suffix “a”, for the baffle board 6 a, the open front end 8 a, the baffle board aperture 10 a, the housing 12 a, the restrictor member 20 a, the front end 26 a of restrictor member 20 a and the mounting fins 36 a.
The housing 12 a is both internally and externally parallel-sided, having no fillets corresponding to the fillets 14 of Figures 1 and 2.
The restrictor member 20 a of Figures 3 and 4 is differently shaped from the restrictor member 20 of Figures 1 and 2, the restrictor member 20 a tapering more abruptly towards its rear end 40 from its maximum width and having a flat, instead of rounded, rear end, so that the forwardly tapering part of the restrictor member 20 a can be positioned more closely to the loudspeaker than in the case of restrictor member 20 The flat rear end 40 of restrictor member 20 a is possible without causing standing waves because of the finite diameter of the loudspeaker voice coil 42 with its curved cover The housing 12 a is clad on :0 the outside thereof with acoustic damping material 44, not shown in Figure 4.
The baffle board 6 a is not essential, provided the loudspeaker edge is sealed acoustically to the rear end of the housing 12 a An acoustically “transparent” covering (not shown) may be placed over the front end of the housing 12 a if desired.

Claims (11)

WHAT I CLAIM IS:-

1 A sound projection system comprising a housing and a longitudinally extending member defining a single longitudinally extending acoustic channel which is substantially annular and acoustically open at a front end of the channel and acoustically 4 closed at a rear end and at sides of the channel, and a loudspeaker having a cone diaphragm operating into the channel at the rear end of the channel, the longitudinally extending member being located directly in front of, and with its longitudinal axis in alignment with the radiation axis of, the loudspeaker, the member having a front portion, which is tapered towards the front of the channel, and a rear portion which is tapered more abruptly than the front portion towards the loudspeaker and projects into the part frusto-conical volume defined by the cone diaphragm.

2 A sound projection system as claimed in Claim I wherein the loudspeakeris mounted in an aperture in a baffle board, the channel extending forwardly of the baffle board.

3 A sound projection system as claimed in Claim 2 wherein the baffle board is at the front of an enclosure.

4 A sound projection system as claimed in Claim 3 wherein the enclosure is a sealed enclosure.

A sound projection system as claimed in any preceding claim, wherein the enclosure and the housing are formed as a single cabinet.

6 A sound projection system as claimed in any preceding claim, wherein the housing is externally parallel sided along its length.

7 A sound projection system as claimed in any preceding claim, wherein the member has a rounded rear end facing the loudspeaker.

8 A sound projection system as claimed in any preceding claim, wherein the member has a f Rat rear end facing the loudspeaker.

9 A sound projection system as claimed in any preceding claim wherein a mounting for the member is adapted to receive a range of such members of various lengths, crosssections and profiles so that the system may be adapted to various working conditions by providing different sound dispersion characteristics.

A sound projection system as claimed in any preceding claim wherein the member is divided along its length into two or more separable sections so that the member of a chosen length, cross-section, profile, and front and rear termination configuration can be assembled from a set of components.

11 A sound projection system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
MARKS & CLERK, Chartered Patent Agents, 57-60 Lincoln’s Inn Fields, London, WC 2 A 3 LS.
Agents for the applicant(s).
Printed for Her Majesty’s Stationery Office, by Croydon Printing Company Limited, Croydon Surrey, 1981.
Published by The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.

GB39603/76A
1976-09-23
1976-09-23
Sound projection system

Expired

GB1592246A
(en)

Priority Applications (7)

Application Number
Priority Date
Filing Date
Title

GB39603/76A

GB1592246A
(en)

1976-09-23
1976-09-23
Sound projection system

CA286,716A

CA1076033A
(en)

1976-09-23
1977-09-14
Sound projection system

US05/833,873

US4181193A
(en)

1976-09-23
1977-09-16
Sound projection system

DE19772742600

DE2742600A1
(en)

1976-09-23
1977-09-22

SOUND RADIATION SYSTEM

JP52113424A

JPS6057759B2
(en)

1976-09-23
1977-09-22

acoustic radiation device

AU29023/77A

AU515535B2
(en)

1976-09-23
1977-09-22
Sound projection system

US06/519,752

USRE32183E
(en)

1976-09-23
1983-08-02
Sound projection system

Applications Claiming Priority (1)

Application Number
Priority Date
Filing Date
Title

GB39603/76A

GB1592246A
(en)

1976-09-23
1976-09-23
Sound projection system

Publications (1)

Publication Number
Publication Date

GB1592246A
true

GB1592246A
(en)

1981-07-01

Family
ID=10410463
Family Applications (1)

Application Number
Title
Priority Date
Filing Date

GB39603/76A
Expired

GB1592246A
(en)

1976-09-23
1976-09-23
Sound projection system

Country Status (6)

Country
Link

US
(1)

US4181193A
(en)

JP
(1)

JPS6057759B2
(en)

AU
(1)

AU515535B2
(en)

CA
(1)

CA1076033A
(en)

DE
(1)

DE2742600A1
(en)

GB
(1)

GB1592246A
(en)

Cited By (1)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

GB2316846A
(en)

1996-08-30
1998-03-04
Harman Int Ind
Loudspeaker horn divided by restrictor element

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(en)

1980-11-28
1989-11-10
Topalian Daniel

ACOUSTIC ENCLOSURE WITH UNFOLDED DOUBLE FRONT PAVILION, AND REAR CLOSED BOX

US4493389A
(en)

1982-05-27
1985-01-15
Luis Del Rosario
Speaker assembly

JPS592435A
(en)

1982-06-29
1984-01-09
Fujitsu Ltd
Ecl circuit

US4628155A
(en)

1982-07-12
1986-12-09
Philippe Robineau
Electroacoustic motor for horns

CA1207673A
(en)

1983-10-28
1986-07-15
John H. Woolley
Method for generating high frequency high level noise fields using low frequency excitation of aeroacoustic noise

HU191275B
(en)

1984-02-14
1987-01-28
Miklos Szegheoe
Device for treating organs by external acoustic waves

US4713799A
(en)

1984-10-15
1987-12-15
Deere & Company
Ultrasonic horn with sidelobe suppressing centerpiece

AU573382B2
(en)

1984-10-15
1988-06-02
Deere & Company
Ultrasonic horn with sidelobe suppression

US4882562A
(en)

1986-03-11
1989-11-21
Turbosound Limited
Adaptor for coupling plural compression drivers to a common horn

US4776428A
(en)

1987-11-16
1988-10-11
Belisle Acoustique Inc.
Sound projection system

FR2627886B1
(en)

1988-02-29
1994-05-13
Heil Christian

CYLINDRICAL SOUND WAVE GUIDE

US6026928A
(en)

1999-04-06
2000-02-22
Maharaj; Ashok A.
Apparatus and method for reduced distortion loudspeakers

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(en)

1999-07-14
1999-09-15
Funktion One Research
Loudspeaker

US6909670B1
(en)

2004-03-19
2005-06-21
Shih-Hsiung Li
Ultrasonic sensor assembly for a vehicle reversing radar

FI120126B
(en)

2004-04-30
2009-06-30
Aura Audio Oy

A method for providing a smooth sound wave front with a planar waveguide, speaker structure and acoustic line emitter

ITRM20060637A1
(en)

2006-11-30
2008-06-01
B & C Speakers S P A

ACOUSTIC WAVE GUIDE AND ELECTROACOUSTIC SYSTEM INCLUDING SUCH WAVE GUIDE

US8958269B2
(en)

2011-05-20
2015-02-17
Vaisala, Inc.
Transducer for phased array acoustic systems

CN103578461B
(en)

2012-07-31
2016-04-06
顾康
A kind of asymmetrical high-frequency sound wave controller with angle adjustable

KR102099236B1
(en)

2019-11-08
2020-04-09
김현철
Super directional speaker

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Arthur Stanley
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1976

1976-09-23
GB
GB39603/76A
patent/GB1592246A/en
not_active
Expired

1977

1977-09-14
CA
CA286,716A
patent/CA1076033A/en
not_active
Expired

1977-09-16
US
US05/833,873
patent/US4181193A/en
not_active
Expired – Lifetime

1977-09-22
DE
DE19772742600
patent/DE2742600A1/en
active
Granted

1977-09-22
JP
JP52113424A
patent/JPS6057759B2/en
not_active
Expired

1977-09-22
AU
AU29023/77A
patent/AU515535B2/en
not_active
Expired

Cited By (2)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

GB2316846A
(en)

1996-08-30
1998-03-04
Harman Int Ind
Loudspeaker horn divided by restrictor element

GB2316846B
(en)

1996-08-30
2000-07-26
Harman Int Ind
Loudspeaker

Also Published As

Publication number
Publication date

JPS5339734A
(en)

1978-04-11

AU2902377A
(en)

1979-03-29

CA1076033A
(en)

1980-04-22

US4181193A
(en)

1980-01-01

DE2742600A1
(en)

1978-03-30

DE2742600C2
(en)

1987-06-11

JPS6057759B2
(en)

1985-12-17

AU515535B2
(en)

1981-04-09

Contact information