EP0048116A1 - Haut-parleur à bobine mobile - Google Patents
Haut-parleur à bobine mobile Download PDFInfo
- Publication number
- EP0048116A1 EP0048116A1 EP81304042A EP81304042A EP0048116A1 EP 0048116 A1 EP0048116 A1 EP 0048116A1 EP 81304042 A EP81304042 A EP 81304042A EP 81304042 A EP81304042 A EP 81304042A EP 0048116 A1 EP0048116 A1 EP 0048116A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- coil
- voice coil
- loudspeaker
- compensation signal
- former
- 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- Withdrawn
Links
- 238000006073 displacement reaction Methods 0.000 claims abstract description 21
- 238000012886 linear function Methods 0.000 claims description 2
- 230000006835 compression Effects 0.000 abstract description 6
- 238000007906 compression Methods 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 5
- 230000010355 oscillation Effects 0.000 abstract description 4
- 230000001419 dependent effect Effects 0.000 description 8
- 230000004907 flux Effects 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 230000003534 oscillatory effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- VIDTVPHHDGRGAF-UHFFFAOYSA-N selenium sulfide Chemical compound [Se]=S VIDTVPHHDGRGAF-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000002463 transducing effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/002—Damping circuit arrangements for transducers, e.g. motional feedback circuits
Definitions
- This invention relates to moving coil loudspeakers.
- Moving coil loudspeakers have a voice coil carried on a former which is attached to the cone or diaphragm of the loudspeaker.
- the voice coil is suspended in a magnetic flux gap between pole pieces of a permanent magnet, and in response to acoustic signals fed to the coil the latter oscillates in the flux gap and drives the loudspeaker cone or diaphragm.
- the frequency response of a moving coil loudspeaker is affected adversely by non-linearity in the relationship between the forces acting upon the voice coil and the displacement of the voice coil from its rest position.
- non-linearity arises, for example, through the fact that as the coil moves further into the flux gap the loudspeaker cone or diaphragm compresses the air in the magnet enclosure, giving rise to a force resisting the displacement of the coil.
- the voice coil tends to move out of the air gap the air trapped beneath the diaphragm or cone is rarified and the displacement of the coil is again resisted.
- a known method of compensating for the above mentioned non-linearity is to provide an additional coil on the same former as the voice coil and to supply this additional coil with a direct current signal (H.Lipschutz, Hi Fi News, April 1980, Page 63).
- the direct current flowing in the additional.coil exerts a force on the former which can be arranged to compensate for the reaction force resulting from compression of the air in the loudspeaker enclosure.
- More than one such additional coil may be mounted on the voice coil former so that both a "pushing" and a “pulling” force is exerted on the voice coil former to compensate for the reaction forces arising from large displacements of the voice coil.
- a practical disadvantage of such known arrangements using DC-fed -; additional coil is that the continuous current flowing in the additional coil or coils generates heat additional to that generated in the voice coil in use of the loudspeaker, and exacerbates the heat dissipation problem.
- the positioning of the or each additional coil has to be accurate for optimum effect, and this inevitably increases the cost of the loudspeaker.
- the present invention seeks to provide a moving coil loudspeaker in which a degree of compensation for non-linearity can be achieved without resorting to the use of an additional DC-fed coil.
- the present invention provides a simple solution to the problem of compensating for non-linearity in loudspeaker response resulting from air compression effects by arranging for a compensation signal derived from a voice coil position sensor to be superimposed on the voice coil signal as a positive feedback signal.
- the positive feedback compensation signal produces a force on the voice coil which counters the forces resulting from compression effects of the loudspeaker cone or diaphragm and from non-linearity of the coil suspension.
- the sensor means are electro-optical and comprise a photoelectric detector and a light source mounted on a central polepiece of the loudspeaker magnet,the voice coil former being provided with a diffusely reflective internal surface the reflecting: characteristics of which vary in the direction of coil displacement to produce the desired compensation signal.
- An advantage of the photoelectric detection system of the present invention is its essential simplicity, since expensive precision optics are not required in association with the light source or the detector.
- the voice coil former is provided with a pattern of non-reflective areas which carry in circumferential width relative to the reflective areas as a linear or non-linear function of distance in the direction of coil displacement.
- the compensation signal may be zero in the rest position of the coil, in contrast to loudspeakers in which an additional direct-current coil is employed. If desired, however, the actual rest position adopted by the voice coil may be compensated by including in the compensation signal a direct-current component.
- a positive feedback compensation signal is superimposed on the acoustic signal fed to the voice coil 6.
- the compensation signal is dependent upon the position of the voice coil relative to this rest position in the air gap 3.
- the compensation signal is derived by direct sensing of the position of the voice coil 6 using optical means.
- An optical transducer unit 7 is mounted on the central pole piece 4 and comprises a phototransistor 8 superimposed upon a light emitting diode 9.
- the light emitting diode 9 directs light onto the internal surface of the coil former 2, this surface being ideally treated or coated so as to be diffusely reflective.
- Light reflected from the former 2 is detected by the phototransistor 8, as illustrated diagrammatically in Figure 1.
- the output signal of the phototransistor 8 will be proportional to the intensity of the light reflected from the internal surface of the former 2, which in turn will be proportional to the amount by which the former 2 projects beyond the end face of the pole piece 4: that is, the output signal of the phototransistor 8 will be dependent upon the displacement of the voice coil 6 from its rest position, and will increase with increasing displacement of the coil.
- the internal surface of the former 2 is uniformly diffusely reflective and the light emitting diode.9 emits a broad beam. Under these conditions the output signal of the phototransistor 8 will be substantially linearly dependent upon the displacement of the coil former 2.
- FIG. 1 Three alternative variants of the embodiment illustrated in Figure 1 are shown by way of example in Figures 2, 3 and 4, in which the same reference numerals have been used to designate the same or corresponding component parts.
- the internal surface of the coil former 2 is provided with a non-linear pattern of reflective areas 10 and non-reflective areas 11 and the light source 9 emits a fan shaped beam, that is, a beam which is narrow in the longitudinal direction of oscillation of the coil 6.
- the area of light reflecting surface presented to the light beam from the source 9 will be non-linearly dependent upon the displacement of the coil former 2 from its rest position.
- the internal surface of the coil former 2 is provided with non-reflective zones 12 at opposite extremes of its reflective surface zone 10, delimiting the maximum excursion of the voice coil 6.
- the beam emitted by the light source 9 lies symmetrically between the two non-reflecting zones 12.
- the reflective surface area 10 of the voice coil former 2 tapers in circumferential width linearly between two extreme zones and the light beam emitted by the source 9 is fan-shaped, as in the variant of Figure 2.
- the area of the reflective surface 10 presented to the light beam emitted by the source 9 will be linearly dependent upon the displacement of the voice coil 6 from its rest position.
- the output of the phototransistor 8 will increase linearly as the voice coil 6 is displaced into the air gap 3 and will decrease linearly as the voice coil 8 is displaced out of the air gap 3.
- a lens or lenses may be associated with the latter, according to whether a narrow pencil beam, a fan-shaped beam, or diffuse radiation is required.
- Figure 5 illustrates diagrammatically an electronic signal processing circuit associated with the phototransistor 8 in the illustrated embodiments for producing the required compensation signal.
- the circuit includes an operational amplifier 14 to which the output of the phototransistor 8 is fed and a second operational amplifier 15 to which the output of the operational amplifier 14 is fed as a positive feedback signal along with the acoustic signal.
- the output of the operational amplifier 15 is applied to the voice coil 6 and will comprise the acoustic signal with the positive feedback compensation signal superimposed thereon.
- the magnitude of the compensation signal relative to the acoustic signal can be predetermined by presetting the gain of the operational amplifier 14 and by adjusting the attenuation of the output of the operational amplifier 14.
- the rest position of the voice coil 6 may be adjusted or compensated by adjustment of the DC level applied to the phototransistor 8.
- the sensing of the voice coil displacement may be effected by detecting the position of any component of the voice coil assembly or its former 2 which moves with the voice coil.
- the light source employed may be of any convenient type, such as an incandescent bulb, a light emitting diode, a solid state laser, a "betalight", a.neon lamp, or a photoemissive device.
- the light receiving device illustrated.in Figures 1 to 4 as a phototransistor may alternatively comprise a photodiode, a selenium sulphide strip, a photoconductive light-dependent resistor or liquid crystal device, or indeed any photoelectrical transducer capable of transducing an electrical output signal which is dependent on the amount of incident light.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Circuit For Audible Band Transducer (AREA)
- Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8028560 | 1980-09-04 | ||
| GB8028560 | 1980-09-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0048116A1 true EP0048116A1 (fr) | 1982-03-24 |
Family
ID=10515843
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP81304042A Withdrawn EP0048116A1 (fr) | 1980-09-04 | 1981-09-04 | Haut-parleur à bobine mobile |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0048116A1 (fr) |
| JP (1) | JPS57118496A (fr) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19604086A1 (de) * | 1996-02-06 | 1997-08-07 | Alfred Ziegenberg | Lautsprecher mit integrierter elektronischer Sensor-Schalldruck-Regelung |
| EP1569497A1 (fr) * | 2004-02-25 | 2005-08-31 | Harman Becker Automotive Systems GmbH | Haut-parleur avec rétroaction motionelle |
| WO2011160020A2 (fr) | 2010-06-18 | 2011-12-22 | Fob Synthesis | Agents antibactériens de carbapénem avec activité anti-gram négatif |
| US20160302018A1 (en) * | 2015-04-09 | 2016-10-13 | Audera Acoustics Inc. | Acoustic transducer systems with position sensing |
| US10516957B2 (en) | 2014-11-28 | 2019-12-24 | Audera Acoustics Inc. | High displacement acoustic transducer systems |
| WO2020050036A1 (fr) * | 2018-09-07 | 2020-03-12 | ヤマハ株式会社 | Dispositif de détection de position |
| CN111193972A (zh) * | 2019-09-29 | 2020-05-22 | 扬州房慧智能科技有限公司 | 一种带照明灯的智能音箱 |
| US11019441B2 (en) | 2019-08-02 | 2021-05-25 | Analog Devices, Inc. | Position sensor for a voice coil |
| US11381908B2 (en) | 2017-08-01 | 2022-07-05 | Michael James Turner | Controller for an electromechanical transducer |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5961693U (ja) * | 1982-10-15 | 1984-04-23 | 株式会社ケンウッド | スピ−カ−用センサ− |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3014096A (en) * | 1956-05-29 | 1961-12-19 | Warner W Clements | Sound reproducing means |
| US3047661A (en) * | 1957-01-18 | 1962-07-31 | Daniel E Winker | High fidelity audio system |
| US3889060A (en) * | 1972-09-11 | 1975-06-10 | Matsushita Electric Industrial Co Ltd | Feedback amplifier distortion-cancelling circuit |
| FR2296985A1 (fr) * | 1975-01-02 | 1976-07-30 | Lan Yan Fock Alain | Compteur-comparateur pour l'asservissement d'un haut-parleur electrodynamique |
| FR2404368A1 (fr) * | 1977-09-27 | 1979-04-20 | Boanich Jacques | Procede et dispositif d'asservissement de l'ensemble mobile d'un reproducteur sonore |
| DE2815368A1 (de) * | 1978-04-10 | 1979-10-18 | Mueller Boehm Dirk | Gegengekoppeltes lautsprechersystem mit optoelektronischer membranabtastung |
| DE2853676A1 (de) * | 1978-12-13 | 1980-06-26 | Licentia Gmbh | Anordnung zur gegenkopplung der bewegung einer lautsprechermembran |
| GB1585759A (en) * | 1977-06-10 | 1981-03-11 | Nat Res Dev | Depressing resonant frequency of a suspended mass |
-
1981
- 1981-09-04 EP EP81304042A patent/EP0048116A1/fr not_active Withdrawn
- 1981-09-04 JP JP13963681A patent/JPS57118496A/ja active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3014096A (en) * | 1956-05-29 | 1961-12-19 | Warner W Clements | Sound reproducing means |
| US3047661A (en) * | 1957-01-18 | 1962-07-31 | Daniel E Winker | High fidelity audio system |
| US3889060A (en) * | 1972-09-11 | 1975-06-10 | Matsushita Electric Industrial Co Ltd | Feedback amplifier distortion-cancelling circuit |
| FR2296985A1 (fr) * | 1975-01-02 | 1976-07-30 | Lan Yan Fock Alain | Compteur-comparateur pour l'asservissement d'un haut-parleur electrodynamique |
| GB1585759A (en) * | 1977-06-10 | 1981-03-11 | Nat Res Dev | Depressing resonant frequency of a suspended mass |
| FR2404368A1 (fr) * | 1977-09-27 | 1979-04-20 | Boanich Jacques | Procede et dispositif d'asservissement de l'ensemble mobile d'un reproducteur sonore |
| DE2815368A1 (de) * | 1978-04-10 | 1979-10-18 | Mueller Boehm Dirk | Gegengekoppeltes lautsprechersystem mit optoelektronischer membranabtastung |
| DE2853676A1 (de) * | 1978-12-13 | 1980-06-26 | Licentia Gmbh | Anordnung zur gegenkopplung der bewegung einer lautsprechermembran |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19604086A1 (de) * | 1996-02-06 | 1997-08-07 | Alfred Ziegenberg | Lautsprecher mit integrierter elektronischer Sensor-Schalldruck-Regelung |
| DE19604086C2 (de) * | 1996-02-06 | 1999-06-10 | Alfred Ziegenberg | Lautsprecher mit integrierter elektronischer Sensor-Schalldruck-Regelung |
| EP1569497A1 (fr) * | 2004-02-25 | 2005-08-31 | Harman Becker Automotive Systems GmbH | Haut-parleur avec rétroaction motionelle |
| WO2011160020A2 (fr) | 2010-06-18 | 2011-12-22 | Fob Synthesis | Agents antibactériens de carbapénem avec activité anti-gram négatif |
| US10516957B2 (en) | 2014-11-28 | 2019-12-24 | Audera Acoustics Inc. | High displacement acoustic transducer systems |
| US20160302018A1 (en) * | 2015-04-09 | 2016-10-13 | Audera Acoustics Inc. | Acoustic transducer systems with position sensing |
| US10034109B2 (en) * | 2015-04-09 | 2018-07-24 | Audera Acoustics Inc. | Acoustic transducer systems with position sensing |
| US20180376269A1 (en) * | 2015-04-09 | 2018-12-27 | Audera Acoustics Inc. | Acoustic transducer systems with position sensing |
| US11381908B2 (en) | 2017-08-01 | 2022-07-05 | Michael James Turner | Controller for an electromechanical transducer |
| WO2020050036A1 (fr) * | 2018-09-07 | 2020-03-12 | ヤマハ株式会社 | Dispositif de détection de position |
| US11019441B2 (en) | 2019-08-02 | 2021-05-25 | Analog Devices, Inc. | Position sensor for a voice coil |
| CN111193972A (zh) * | 2019-09-29 | 2020-05-22 | 扬州房慧智能科技有限公司 | 一种带照明灯的智能音箱 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57118496A (en) | 1982-07-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Designated state(s): DE FR IT NL |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
| 18W | Application withdrawn |
Withdrawal date: 19820311 |
|
| RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: DIBB, JOHN JOSEPH Inventor name: FRYER, PETER ALEXANDER |