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EP0639317A1 - Systeme de haut-parleur - Google Patents

Systeme de haut-parleur

Info

Publication number
EP0639317A1
EP0639317A1 EP93903022A EP93903022A EP0639317A1 EP 0639317 A1 EP0639317 A1 EP 0639317A1 EP 93903022 A EP93903022 A EP 93903022A EP 93903022 A EP93903022 A EP 93903022A EP 0639317 A1 EP0639317 A1 EP 0639317A1
Authority
EP
European Patent Office
Prior art keywords
loudspeaker
enclosure
channel
frequency range
degrees
Prior art date
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.)
Withdrawn
Application number
EP93903022A
Other languages
German (de)
English (en)
Other versions
EP0639317A4 (fr
Inventor
Sevag Hrair 20 Sheafe Street Arzoumanian
Hal Perry Greenberger
Richard Harold Lyon
Bradley Mark Starobin
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.)
Technicolor USA Inc
Original Assignee
Thomson Consumer Electronics 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 Thomson Consumer Electronics Inc filed Critical Thomson Consumer Electronics Inc
Publication of EP0639317A4 publication Critical patent/EP0639317A4/fr
Publication of EP0639317A1 publication Critical patent/EP0639317A1/fr
Withdrawn legal-status Critical Current

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
    • H04R5/00—Stereophonic arrangements
    • H04R5/02—Spatial or constructional arrangements of loudspeakers

Definitions

  • the present invention relates to loudspeaker systems, and more particularly to a center channel loudspeaker system for a DOLBY PRO LOGIC home theater system.
  • the Dolby system is a stereophonic system which includes surround sound encoding based upon 4-2-4 matrix methods for four-channel recording devised in the early 1970's.
  • the four original signals are mixed to make a two channel stereo recording which is decoded upon playback to recover an approximation of the original four channels, which are left, center, right, and surround.
  • the center channel signal is added to the left and right channels as a monophonic in-phase signal.
  • the surround channel signal is added to the left and right channel signals but as an out- of-phase signal.
  • the total left and total right channels are added together in a decoder to recover the center channel signal while the L-R subtraction extracts the out- of-phase surround channel signal.
  • Logic steering circuitry is used upon decoding to increase the apparent separation of the left, center, right, and surround signal.
  • the surround channel signal is delayed by about 20 milliseconds to prevent unwanted location of frontal sounds in the surround channel loudspeakers.
  • the center channel provides most of the dialogue for a motion picture or a television program, and carries music and effects sounds as well.
  • the purpose of the center channel is to insure that voices and other sounds originating from on-screen sources, will appear to come from the screen even when viewers are seated off-center.
  • the center channel loudspeaker system must be capable of generating the same acoustic output levels as the left and right loudspeakers over its operating frequency range.
  • center channel loudspeaker system should be located as physically close to the television screen as possible to maintain the fusion of the visual and auditory images.
  • the most practical location to locate the center channel loudspeaker system in a typical living room is either on top of or underneath the television receiver. This requires that the center channel loudspeaker system be compact.
  • the need for compactness, along with a minimum radiating area requirement, are important design considerations for a center channel loudspeaker system.
  • the acoustic outputs from the two sources will interfere destructively causing large notches in the frequency response of the system.
  • This "notching" similar to a comb filter, causes a perceptible degradation in the quality of the sound. It is desirable to minimize this destructive interference so that off axis listeners will not suffer from degraded sound quality.
  • the destructive interference that occurs due to the two woofers displaced in space having the same acoustic radiation can also occur in the crossover frequency range where the woofers and tweeter are both operating. It is desirable to minimize this source of destructive interference.
  • a center channel loudspeaker system for use with a Dolby four channel sound system is presented.
  • a first loudspeaker is mounted at the front of an enclosure.
  • Second and third loudspeakers are mounted at the front of the enclosure, one on each side of the first loudspeaker, at an angle of approximately 40 degrees in the vertical plane back from the first loudspeaker.
  • FIG. 1 shows a representation of a prior art center loudspeaker system with the listeners being exposed to cancellation of sound due to destructive interference.
  • FIG. 2 shows a representation of a center loudspeaker system, according to aspects of the present invention, showing how cancellation of the sound due to destructive interference is minimized.
  • FIG. 1 shows loudspeaker enclosure arrangement according to the prior art.
  • the loudspeaker enclosures shown are for three channels, i.e., left, right, and center, for a Dolby Pro-Logic system, with the surround loudspeakers not shown.
  • the left and right stereophonic loudspeakers are any appropriate loudspeakers suitable for the purpose, and receive standard left and right signals.
  • the structure and operation of the left and right stereophonic sound radiating loudspeakers form no part of the present invention and will not be discussed further.
  • FIG. 1 shows a prior art center loudspeaker system comprised of a pair of 5.25 inch drivers 12 and 14 mounted within a common enclosure 16.
  • Drivers 12 and 14 cover the low and middle frequency ranges.
  • a horn tweeter 18, covering the high frequency range, is mounted between drivers 12, 14.
  • the loudspeaker radiation would produce nulls in the combined response of the two drivers 12, 14. Only in regions A, B, and C would the response be reasonably accurate.
  • the radiation from both drivers 12, 14 would be sufficiently strong to cause cancellation effects, since the path length differences between a listener in these regions and the two drivers is a significant fraction of a wavelength, or even multiple wavelengths within the similar passbands of the two drivers.
  • the polar response for non-optimized loudspeakers includes wide angular spaces in which destructive interference between the acoustic radiation of drivers 12, 14 occurs.
  • each of the 5.25 inch drivers 12, 14 of the exemplary embodiment are mounted at a backward angle of approximately 40 degrees, e.g., 37.5 degrees, within the vertical plane, with respect to loudspeaker 18.
  • the optimum angle will be different for different sized and different frequency range loudspeakers. With such a mounting angle, as one moves off -axis to center loudspeaker 18, one moves on-axis to one of drivers 12, 14, and further off-axis to the other one of drivers 12, 14.
  • horn loudspeaker 18 is mounted so that its acoustic center is approximately 4.5 cm behind the front panel of the speaker (not shown) with the optimal displacement depending on the characteristics of the particular loudspeakers used. This places the acoustic center of loudspeaker 18 in close but not in exact alignment with the acoustic centers of loudspeakers 12 and 14.
  • FIG. 2 shows the approximate coverage of the two mid-woofers 12, 14 just below the frequency at which the crossover frequency for the tweeter 18 occurs in the exemplary center channel loudspeaker system.
  • region A the acoustic outputs of drivers 12, 14 arrive essentially in phase and no cancellations occur.
  • regions B and C the acoustic outputs of loudspeakers 12 and 14 will be shifted in phase with respect to each other.
  • the net effect on the system is small because the mounting angle of loudspeakers 12, 14 significantly reduces the sound level from the further loudspeaker with respect to the nearer loudspeaker.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Stereophonic System (AREA)

Abstract

Système de haut parleur à voie centrale destiné à être utilisé avec un système acoustique à quatre voies 'Dolby'. Un premier (18) haut-parleur est monté sur le devant d'une enceinte (10). Des deuxième (12) et troisième (14) haut-parleurs dont les cônes sont plus grands que celui du premier (18) haut-parleur et dont la gamme de fréquences est inférieure à celle du premier (18) haut-parleur, sont montés sur le devant d'une enceinte (10) de chaque côté du premier (18) haut-parleur, suivant un arc de 40 dégres environ dans le plan vertical à l'arrière du premier (18) haut-parleur. Cette disposition permet de minimiser la suppresion destructrice du son émanant des haut-parleurs à voie centrale qui ne sont pas très éloignés.
EP93903022A 1992-01-08 1993-01-08 Systeme de haut-parleur Withdrawn EP0639317A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9200302 1992-01-08
GB929200302A GB9200302D0 (en) 1992-01-08 1992-01-08 Loud speaker systems
PCT/US1993/000151 WO1993014606A1 (fr) 1992-01-08 1993-01-08 Systeme de haut-parleur

Publications (2)

Publication Number Publication Date
EP0639317A4 EP0639317A4 (fr) 1994-10-17
EP0639317A1 true EP0639317A1 (fr) 1995-02-22

Family

ID=10708255

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93903022A Withdrawn EP0639317A1 (fr) 1992-01-08 1993-01-08 Systeme de haut-parleur

Country Status (6)

Country Link
EP (1) EP0639317A1 (fr)
JP (1) JPH07503112A (fr)
KR (1) KR940704110A (fr)
CA (1) CA2117383A1 (fr)
GB (1) GB9200302D0 (fr)
WO (1) WO1993014606A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8139797B2 (en) 2002-12-03 2012-03-20 Bose Corporation Directional electroacoustical transducing
US7676047B2 (en) 2002-12-03 2010-03-09 Bose Corporation Electroacoustical transducing with low frequency augmenting devices
US7688992B2 (en) 2005-09-12 2010-03-30 Richard Aylward Seat electroacoustical transducing
US8483413B2 (en) 2007-05-04 2013-07-09 Bose Corporation System and method for directionally radiating sound
US9100748B2 (en) 2007-05-04 2015-08-04 Bose Corporation System and method for directionally radiating sound
BR112013031157A2 (pt) * 2011-06-09 2017-02-07 Koninklijke Philips Nv arranjo de alto-falante e método de prover um arranjo de alto-falante
EP3041265B1 (fr) * 2014-09-08 2019-12-18 Adamson Systems Engineering Inc. Haut-parleur à comportement directionnel amélioré et réduction des interférences acoustiques

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3983333A (en) * 1974-03-01 1976-09-28 Allison Acoustics Inc. Loud speaker system
DE2910117A1 (de) * 1978-03-16 1979-09-20 Akg Akustische Kino Geraete Anordnung zur wiedergabe zweikanalig uebertragener schallereignisse
WO1990005434A1 (fr) * 1988-11-08 1990-05-17 Timo Tarkkonen Agencement de haut-parleur

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2143175A (en) * 1937-10-23 1939-01-10 Samuel A Waite Sound reproducing system
US3026957A (en) * 1959-06-02 1962-03-27 Gladstone Lewis Loudspeaker system
US4073365A (en) * 1977-07-11 1978-02-14 Johnson Joseph W Speaker system
US4888804A (en) * 1988-05-12 1989-12-19 Gefvert Herbert I Sound reproduction system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3983333A (en) * 1974-03-01 1976-09-28 Allison Acoustics Inc. Loud speaker system
DE2910117A1 (de) * 1978-03-16 1979-09-20 Akg Akustische Kino Geraete Anordnung zur wiedergabe zweikanalig uebertragener schallereignisse
WO1990005434A1 (fr) * 1988-11-08 1990-05-17 Timo Tarkkonen Agencement de haut-parleur

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
FERNSEH UND KINO TECHNIK, vol.45, no.6, June 1991, BERLIN DE pages 297 - 306, XP000234650 G. STEINKE 'Von der Ambiophonie zur HDTV-Heim-Beschallung' *
See also references of WO9314606A1 *

Also Published As

Publication number Publication date
GB9200302D0 (en) 1992-02-26
KR940704110A (ko) 1994-12-12
EP0639317A4 (fr) 1994-10-17
WO1993014606A1 (fr) 1993-07-22
CA2117383A1 (fr) 1993-07-22
JPH07503112A (ja) 1995-03-30

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