EP0692922A2 - Enceinte acoustique pour haut-parleur basse-fréquence - Google Patents

Enceinte acoustique pour haut-parleur basse-fréquence Download PDF

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Publication number
EP0692922A2
EP0692922A2 EP95111048A EP95111048A EP0692922A2 EP 0692922 A2 EP0692922 A2 EP 0692922A2 EP 95111048 A EP95111048 A EP 95111048A EP 95111048 A EP95111048 A EP 95111048A EP 0692922 A2 EP0692922 A2 EP 0692922A2
Authority
EP
European Patent Office
Prior art keywords
sound
chamber
woofers
loudspeaker housing
sound chamber
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.)
Granted
Application number
EP95111048A
Other languages
German (de)
English (en)
Other versions
EP0692922A3 (fr
EP0692922B1 (fr
Inventor
Siegfried Krüger
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.)
Nokia Technology GmbH
Original Assignee
Nokia Technology GmbH
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 Nokia Technology GmbH filed Critical Nokia Technology GmbH
Publication of EP0692922A2 publication Critical patent/EP0692922A2/fr
Publication of EP0692922A3 publication Critical patent/EP0692922A3/fr
Application granted granted Critical
Publication of EP0692922B1 publication Critical patent/EP0692922B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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
    • H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein

Definitions

  • the invention relates to a housing for bass speakers, which is constructed on the principle of an acoustic bandpass filter.
  • a loudspeaker housing is provided in a special case for improving the sound reproduction of television sets.
  • the problem with the constructive and aesthetic design of television sets is that the sound part has to be subordinate to the design of the image reproduction part.
  • the screen represents the optically dominating part of a television set and for the sound emitters there are generally only narrow areas in the area of the edges, the sound emitters being arranged so that they are barely perceptible to the viewer.
  • the efficiency in the bass range and the lower limit frequency to be expected are lower in a loudspeaker system, the lower the natural resonance of the loudspeaker and the larger the diameter of the membrane of the loudspeaker.
  • loudspeakers require housings with a large closed volume in order to avoid an acoustic short circuit.
  • televisions have too little surface area and an insufficient usable volume in order to ensure optimal conditions for good bass reproduction in the range of, for. B. to create under 150 Hz.
  • the electrical signal power is often limited, since the electrical operating power for the audio amplifiers is provided by a switching power supply which can only supply electrical power to a limited extent at low cost, so that the output power of the audio amplifiers from television sets is usually only less than 2 ⁇ 15 watts at 2 x 8 ohm speaker impedance.
  • a significantly higher sound pressure is required in the bass range than in the mid-range range, this low output power and long-throw woofers cannot produce sufficient sound pressure for good bass reproduction.
  • broadband loudspeakers with a resonance frequency of over 120 Hz are usually used in television sets, which only inadequately reproduce the range up to 60 Hz.
  • woofers in housings that act as acoustic Resonators are designed to be arranged.
  • Known embodiments use the frequency response of a Helmholtz resonator (see DE magazine “Klang &Ton", 1993, Issue 2, pages 48-51).
  • This principle has considerable advantages over other types of housings, such as. B. a low cut-off frequency with a relatively small volume, better acoustic efficiency and a steep filter curve in the range of the upper and lower cut-off frequency of at least 12 dB per octave.
  • the basic design of such a housing consists of a closed and an open, tuned to a resonance frequency, sound chamber with a bass reflex opening. A coordinated sound outlet channel is arranged in this, which realizes the sound emission.
  • the housing is a combination of a compact housing and a Helmholtz resonator, with a resonance frequency f c .
  • the properties of this speaker system are determined on the one hand by the characteristic values of the woofer: Open-air resonance f o , equivalent volume V as , open-air quality Q t and effective radiator area and, on the other hand, determined by the housing parameters: volume V b1 of the closed sound chamber, volume V b2 of the open sound chamber, the damping of the sound chambers and the geometric dimensions of the sound outlet channel.
  • the housing parameters the acoustic properties of the system: Resonance frequency, bandwidth, ripple of the resonance curve and acoustic efficiency can be varied.
  • the efficiency of the bandpass system can be increased.
  • the bandwidth B of the system decreases.
  • Such a housing with two woofers can generate a sound pressure P s of around 90 dB, for example with careful dimensioning in a reproduction range from 50 Hz to 120 Hz with 2 x 1 watt electrical signal power. Compared to other systems, this is a remarkable acoustic efficiency. However, this value is also still too low for the intended application.
  • a television set with a stereo sound part in which two ventilated sound chambers for woofers are arranged acoustically separated from the tweeters and mid-range speakers in the housing of the television set.
  • the two woofers to each of which the output signal of a stereo channel is fed, are arranged and acoustically connected in openings in a sound partition, which is located between the sound chambers in the television set, so that each woofer feeds both ventilated sound chambers.
  • the sound chambers have different volumes.
  • both chambers each have a sound outlet channel for emitting the sound. This creates a bandpass with two ventilated sound chambers that are tuned to different resonance frequencies to achieve a wide bass range.
  • Such a loudspeaker system has the advantage that the loudspeaker housings for the high and mid-range can be realized without reducing the reproduction quality with a small volume and that only one housing with a high expenditure of material and volume is required for the reproduction of the bass range of both stereo channels.
  • the two woofers are each assigned to another of the two stereo channels. Both woofers work in the same frequency range on a pair of chambers consisting of differently tuned ventilated sound chambers.
  • Figure 1 a shows that with this dimensioning in a frequency range from 58 Hz to 170 Hz with 2 x 1 watt electrical signal power, a sound pressure P s between 90 dB and 96 dB can be realized, but the linearity of the sound pressure P s is unsatisfactory . Better linearity can be expected if the housing is dimensioned for an optimal frequency response. In this case, however, the aforementioned sound pressure cannot be achieved.
  • the tuning frequencies f cF and f cR of the two sound chambers must be far apart.
  • the rear ventilated chamber therefore needs a sound outlet duct with a length of 37.6 cm and a cross section of 50 cm2.
  • Figure 1 b) shows the course of the deflection of the voice coil from the woofer. It can be seen that the voice coil is deflected with minimal amplitude at the tuning frequencies f cF and f cR . The disadvantage, however, is that the voice coil has significantly larger amplitudes outside of these frequencies. In the example, the curve has a first amplitude maximum of 4 mm and a second amplitude maximum of 1.5 mm.
  • the woofer Although the frequency at the first maximum value of 25 Hz is at the lower edge of the bandpass range of the loudspeaker housing, the woofer must be able to carry out these high amplitudes without distortion if this frequency occurs in the electrical signal. Otherwise, the harmonics caused by distortion would be radiated more intensely by the resonator effect. In order to achieve such high diaphragm deflections without distortion, long-throw woofers have to be used and these make the effort considerably more expensive.
  • a fundamental disadvantage of bandpass housings is the occurrence of undesirable resonances for r in the sound exit channels above the bass range, which falsify the timbre of the reproduction. These resonances for r are usually between 500 and 1000 Hz and have to be filtered electrically.
  • the invention is therefore based on the object to provide a loudspeaker housing for the low frequency range below approximately 150 Hz, which generates a higher sound pressure P s compared to the known solutions with a small volume, inexpensive woofers and low electrical power.
  • the invention makes use of the knowledge that the signals from the stereo channels are approximately the same in the low-frequency range. It is also possible to accommodate the woofers for both stereo channels in one housing, since the location of the sound is greatly reduced below 200 Hz. This makes it possible to use the woofers that are available for each stereo channel, regardless of the stereo channel to which they are assigned, in a different frequency range to generate sound pressure.
  • each woofer is arranged in the opening of an intermediate wall of a separate sound chamber system.
  • a separate sound chamber system consists of both a closed sound chamber and an open sound chamber designed as a bandpass filter with a coordinated sound output.
  • the sound chamber systems are acoustically separated from each other so that each woofer produces sound pressure in a selected frequency range, unaffected by the other system.
  • the systems are primarily coordinated with the aspect of achieving a particularly high sound pressure in a selected frequency range of the bass range, without sufficient sound pressure being achieved with a single system over the entire bass range becomes.
  • FIG. 2 shows a loudspeaker housing 1 with a predetermined volume V o .
  • this is divided by sound dividing walls 2.1 and 2.2 with openings 3 and sound dividing walls 2.3 and 2.4 without openings into two closed sound chambers 6.1 and 6.2 and two ventilated sound chambers 7.1 and 7.2.
  • a woofer 4.1 and 4.2 is arranged in the openings 3 of the sound dividing walls 2.1 and 2.2.
  • the sound dividing walls 2.3 and 2.4 without openings separate the loudspeaker housing 1 into two acoustically independent sound chamber systems 5.1 and 5.2, each of which contains a closed sound chamber 6.1 or 6.2 and a ventilated sound chamber 7.1 or 7.2.
  • the sound chamber systems 5.1 and 5.2 are tuned to different tuning frequencies f c1 and f c2 and bandwidths B1 and B2.
  • the tuning frequencies f c1 and f c2 and bandwidths B1 and B2 are preferably chosen so that the sound pressure at the transition frequency f t , at which the falling frequency curve of the sound chamber system 5.1 crosses with the rising frequency curve of the sound chamber system 5.2 P s is reduced by 3 dB compared to the maximum.
  • the Sound chamber system 5.1 which is dimensioned for the lower tuning frequency f c1, is tuned by both systems to the lower bandwidth B1.
  • each of the woofers 4.1, 4.2 of the sound chamber systems 5.1, 5.2 is in a different sub-frequency range of the desired bass range, which in the example is from 50 to 130 Hz is sufficient and has a low ripple with optimal efficiency sound pressure P s generated.
  • the loudspeaker housing 1 according to the invention thus contains, instead of the known two large sound chambers, each of which has a different tuning frequency f c1 and f c2 , two small sound chamber systems 5.1 and 5.2, each of which is formed by the known simple basic system, each with an open and a closed sound chamber.
  • FIG. 4 c) shows the deflection of the voice coils of the woofers in the housing according to the invention as a function of the playback frequency.
  • f c1 65 Hz
  • the basic system of a bandpass with a closed sound chamber and a ventilated sound chamber can in principle be expected to have a poorer efficiency.
  • a higher sound pressure P s can be achieved either with a certain nominal power, a given woofer type and volume or with the same volume and smaller woofers the same sound pressure compared to the basic design.
  • the loudspeaker enclosure according to the invention has advantages over the two-chamber housings with two reflex ports and two woofers the advantage that the same electrical signal power, a gain in sound pressure P from 2 to 3 dB is possible over the entire low frequency range, as a result of the attenuation due to the relatively small volume of the closed sound chambers 6.1 or 6.2, the diaphragm deflections of the woofers are significantly reduced. In this way, simple inexpensive standard speakers can be used.
  • the phase positions of the emitted sound waves can also be coordinated with one another.
  • this can be done electrically.
  • different values can be selected for the inductors, which are usually connected in series with the voice coils of the woofers in order to prevent them from consuming signal power in the mid and high range.
  • the sound dividing walls 2.1 and 2.2 with the woofers 4.1 and 4.2 can be arranged in their position in relation to the inner openings of the sound outlet channels 8.1 and 8.2 in such a way that sound paths L1 and L2 and so that there are differences in the length of the running time of the sound in both systems.
  • the sound waves leave the sound chamber systems 5.1 and 5.2 with different Phase position.
  • the phase positions can be selected so that with a sound signal that both woofers 4.1 and 4.2 emit into the room at the transition area from the sound chamber system 5.1 to the sound chamber system 5.2 with the transition frequency f t , the phase difference at the bass reflex openings is minimal.
  • phase relationship between the systems can be varied slightly enough that the undesirable resonances f r described , which occur in the sound exit channels above the bass range and which distort the timbre of the reproduction, at least in their lower range, are extinguished as a result of the opposite phase position of the emerging sound waves.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
EP95111048A 1994-07-15 1995-07-14 Enceinte acoustique pour haut-parleur basse-fréquence Expired - Lifetime EP0692922B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4424995A DE4424995A1 (de) 1994-07-15 1994-07-15 Gehäuse für Baßlautsprecher
DE4424995 1994-07-15

Publications (3)

Publication Number Publication Date
EP0692922A2 true EP0692922A2 (fr) 1996-01-17
EP0692922A3 EP0692922A3 (fr) 1997-06-25
EP0692922B1 EP0692922B1 (fr) 1998-08-19

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EP95111048A Expired - Lifetime EP0692922B1 (fr) 1994-07-15 1995-07-14 Enceinte acoustique pour haut-parleur basse-fréquence

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EP (1) EP0692922B1 (fr)
DE (2) DE4424995A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1372354A2 (fr) * 2002-06-14 2003-12-17 Anthony John Andrews Haut-parleur à basse fréquence
DE102004025146A1 (de) * 2004-05-21 2005-12-22 Elac Electroacustic Gmbh Tiefton-Lautsprecher
CN113596672A (zh) * 2020-04-30 2021-11-02 华为技术有限公司 扬声器模组及电子设备
CN113810800A (zh) * 2021-09-16 2021-12-17 维沃移动通信有限公司 扬声器模组及其声音调节方法、装置和电子设备

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013110535B4 (de) 2013-09-24 2018-03-01 D&B Audiotechnik Gmbh Bassreflex-Lautsprechersystem mit Phasenkorrekturelement

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3892288A (en) * 1971-10-02 1975-07-01 Monitron Ind Speaker enclosure
JPH02309798A (ja) * 1989-05-24 1990-12-25 Kenwood Corp 低音スピーカシステム
US4984653A (en) * 1986-12-02 1991-01-15 Wolfgang Spors Loudspeaker arrangement
EP0532280A2 (fr) * 1991-09-10 1993-03-17 Sony Corporation Configuration de haut-parleur pour un appareil de télévision

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU720830A1 (ru) * 1978-07-07 1980-03-05 Киевский Ордена Ленина Политехнический Институт Им. 50-Летия Великой Октябрьской Социалистической Революции Акустическое устройство
DE3317518A1 (de) * 1983-05-13 1984-11-15 Standard Elektrik Lorenz Ag Lautsprecherbox mit integriertem akustischem bandpassfilter

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3892288A (en) * 1971-10-02 1975-07-01 Monitron Ind Speaker enclosure
US4984653A (en) * 1986-12-02 1991-01-15 Wolfgang Spors Loudspeaker arrangement
JPH02309798A (ja) * 1989-05-24 1990-12-25 Kenwood Corp 低音スピーカシステム
EP0532280A2 (fr) * 1991-09-10 1993-03-17 Sony Corporation Configuration de haut-parleur pour un appareil de télévision

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 015, no. 102 (E-1043), 12.März 1991 & JP 02 309798 A (KENWOOD CORP), 25.Dezember 1990, *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1372354A2 (fr) * 2002-06-14 2003-12-17 Anthony John Andrews Haut-parleur à basse fréquence
EP1372354A3 (fr) * 2002-06-14 2005-11-23 Anthony John Andrews Haut-parleur à basse fréquence
DE102004025146A1 (de) * 2004-05-21 2005-12-22 Elac Electroacustic Gmbh Tiefton-Lautsprecher
DE102004025146B4 (de) * 2004-05-21 2006-06-01 Elac Electroacustic Gmbh Tiefton-Lautsprecher
CN113596672A (zh) * 2020-04-30 2021-11-02 华为技术有限公司 扬声器模组及电子设备
CN113596672B (zh) * 2020-04-30 2022-11-22 华为技术有限公司 扬声器模组及电子设备
CN113810800A (zh) * 2021-09-16 2021-12-17 维沃移动通信有限公司 扬声器模组及其声音调节方法、装置和电子设备
CN113810800B (zh) * 2021-09-16 2024-01-09 维沃移动通信有限公司 扬声器模组及其声音调节方法、装置和电子设备

Also Published As

Publication number Publication date
DE59503239D1 (de) 1998-09-24
EP0692922A3 (fr) 1997-06-25
EP0692922B1 (fr) 1998-08-19
DE4424995A1 (de) 1996-01-18

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