EP2456229A1 - Lautsprechersystem und Steuerverfahren - Google Patents

Lautsprechersystem und Steuerverfahren Download PDF

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Publication number
EP2456229A1
EP2456229A1 EP10191594A EP10191594A EP2456229A1 EP 2456229 A1 EP2456229 A1 EP 2456229A1 EP 10191594 A EP10191594 A EP 10191594A EP 10191594 A EP10191594 A EP 10191594A EP 2456229 A1 EP2456229 A1 EP 2456229A1
Authority
EP
European Patent Office
Prior art keywords
loudspeaker
displacement
signal
estimated
pressure
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Withdrawn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
EP10191594A
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English (en)
French (fr)
Inventor
Temujin Gautama
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.)
Knowles Electronics Asia Pte Ltd
Original Assignee
Knowles Electronics Asia Pte Ltd
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 Knowles Electronics Asia Pte Ltd filed Critical Knowles Electronics Asia Pte Ltd
Priority to EP10191594A priority Critical patent/EP2456229A1/de
Priority to PCT/EP2011/070235 priority patent/WO2012066029A1/en
Publication of EP2456229A1 publication Critical patent/EP2456229A1/de
Withdrawn legal-status Critical Current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
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/002—Damping circuit arrangements for transducers, e.g. motional feedback circuits
    • 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
    • H04R3/007—Protection circuits for transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R29/00—Monitoring arrangements; Testing arrangements
    • H04R29/001—Monitoring arrangements; Testing arrangements for loudspeakers
    • H04R29/003—Monitoring arrangements; Testing arrangements for loudspeakers of the moving-coil type

Definitions

  • This invention relates to a loudspeaker system.
  • variable cutoff filters high-pass or other
  • gain stage a gain stage
  • dynamic range compression module the characteristics of which are controlled via a control feedback loop.
  • the measured control signal is referred to as the displacement predictor and it conveys information on how close the loudspeaker is driven to the displacement limit by the input signal.
  • the control method requires modelling of the loudspeaker characteristics so that the displacement can be predicted in response to a given input signal.
  • the model predicts the diaphragm displacement, also referred to as cone excursion, and it can be linear or non-linear.
  • the control system can be used for loudspeaker protection as mentioned above and also linearisation of the loudspeaker output.
  • the input signal is typically pre-processed in such a way that the predicted displacement stays below the limit.
  • the parameters of the loudspeaker model which is used for the prediction of the displacement, are estimated on the basis of measurements of the voltage across and the current flowing into the loudspeaker voice coil.
  • the voice coil voltage and current are thus required.
  • dedicated hardware is required, for example a resistor in series with the voice coil. This affects the electrical characteristics of the loudspeaker circuit or may be cumbersome to implement in such a way that the measurements are for example independent of temperature changes.
  • a loudspeaker system comprising:
  • the pressure sensor is used to record the pressure in the sealed enclosure, and this is used to characterise the loudspeaker membrane displacement.
  • the invention is based on the recognition that a pressure sensor registers a signal that can be used as a measure of the diaphragm displacement.
  • a loudspeaker model can be estimated without a means for sensing the current.
  • a pressure sensor signal can be used, which only requires standard hardware. Since the pressure sensor signal is directly related to the diaphragm displacement, it yields more accurate information than the voice coil current signal with respect to the loudspeaker non-linearities. Therefore, non-linear models can be more easily and more accurately estimated.
  • Information regarding the diaphragm displacement can also be obtained using an accelerometer that is mounted onto the loudspeaker diaphragm.
  • the mounting of the accelerometer would have a considerable effect on the properties of the loudspeaker.
  • the pressure sensor can comprise a microphone and the sealed enclosure can comprise the loudspeaker back volume.
  • the processor is preferably adapted to implement loudspeaker protection on the basis of the estimated loudspeaker membrane displacement.
  • This estimated loudspeaker membrane displacement can thus be derived without voice coil current or voltage monitoring.
  • the invention also provides a method of controlling a loudspeaker output, comprising:
  • the invention provides a system which combines a loudspeaker, a sealed loudspeaker enclosure and a pressure sensor in the sealed enclosure, preferably implemented as a microphone.
  • the signal registered by the microphone within the loudspeaker enclosure is a signal that is directly related to the loudspeaker diaphragm displacement.
  • FIG 1 shows in schematic form the system of the invention.
  • the system comprises a loudspeaker 10 mounted in a sealed enclosure 12, thus corresponding to a closed-box configuration.
  • a microphone 14 is mounted within in the sealed enclosure 12.
  • the microphone can be a completely separate off-the-shelf component that is simply mounted in the enclosure
  • the volume of the enclosure is changed, due to which the pressure within the enclosure changes.
  • the microphone that is mounted within the enclosure registers the pressure, and therefore, the microphone signal is related to the diaphragm displacement.
  • the microphone signal can be used to estimate the loudspeaker model parameters.
  • the electrical impedance which is the frequency transfer function between voice coil voltage and current
  • the model parameters are obtained by minimising the discrepancy between the measured impedance and the impedance predicted by the model with respect to the model parameters.
  • model parameters can be obtained by minimising the discrepancy between the voltage-to-excursion transfer function that is measured and that predicted by the model with respect to the model parameters. In this way, the expected displacement for a given input signal can be predicted before the signal is sent to the loudspeaker.
  • the microphone signal can instead be used directly as a measure of the diaphragm displacement (without the need for a model).
  • the displacement for a given input signal is estimated after the signal is sent to the loudspeaker.
  • a pressure sensor signal can be used to determine voice coil displacement
  • the diaphragm displacement has been measured for one speaker design using a laser displacement meter, and the signal has been compared to the signal recorded by a microphone that is mounted within the same sealed loudspeaker enclosure.
  • the frequency transfer functions from source signal to the laser signal and to the microphone signal are computed and shown in Figure 2 .
  • the invention can be used in systems that are aimed at loudspeaker modelling, protection and linearisation.
  • the signal registered by the microphone can also be used as a reference signal for acoustic echo cancellation (AEC), which offers the advantage that the microphone signal contains the nonlinearities that are due to the non-linear behaviour of the loudspeaker.
  • AEC acoustic echo cancellation
  • FIG. 3 shows a loudspeaker system of the invention.
  • a digital-to-analog converter 30 prepares the analog loudspeaker signal, which is amplified by amplifier 32.
  • the microphone (or other pressure sensor) 14 is used to estimate the loudspeaker displacement, and the displacement estimator is provided to a processor 34, which implements a control algorithm to control the audio processing. This implements loudspeaker protection and/or acoustic signal processing (such as flattening, or frequency selective filtering).
  • the way the displacement signal is used is the same as the way the known displacement estimate derived from electrical analysis or from optical analysis is used. Thus, the acoustic signal processing is not described in detail in this application.
  • Figure 4 shows the control method of the invention.
  • Step 40 comprises the pressure detection in the sealed enclosure in which the loudspeaker is housed.
  • Step 42 comprises estimating the loudspeaker diaphragm displacement from the detected pressure. As shown in Figure 2 , the pressure signal is linearly proportional to the displacement.
  • the microphone sensitivity may be calibrated in such a way that the relationship to the diaphragm displacement is known on an absolute scale. This can be done in a calibration step, where for a given input test signal, the diaphragm displacement is measured (or known) and is related to the microphone signal.
  • Step 44 comprises the known control of the audio processing for the loudspeaker in dependence on the loudspeaker membrane displacement.
  • the invention is based on the recognition that pressure sensing within the loudspeaker enclosure can be used to estimate the loudspeaker diaphragm displacement.
  • the invention can be used in miniature loudspeakers, such as used in portable battery operated devices, such as mobile phones, but it may equally be used in larger devices.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Circuit For Audible Band Transducer (AREA)
EP10191594A 2010-11-17 2010-11-17 Lautsprechersystem und Steuerverfahren Withdrawn EP2456229A1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP10191594A EP2456229A1 (de) 2010-11-17 2010-11-17 Lautsprechersystem und Steuerverfahren
PCT/EP2011/070235 WO2012066029A1 (en) 2010-11-17 2011-11-16 Loudspeaker system and control method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP10191594A EP2456229A1 (de) 2010-11-17 2010-11-17 Lautsprechersystem und Steuerverfahren

Publications (1)

Publication Number Publication Date
EP2456229A1 true EP2456229A1 (de) 2012-05-23

Family

ID=43734152

Family Applications (1)

Application Number Title Priority Date Filing Date
EP10191594A Withdrawn EP2456229A1 (de) 2010-11-17 2010-11-17 Lautsprechersystem und Steuerverfahren

Country Status (2)

Country Link
EP (1) EP2456229A1 (de)
WO (1) WO2012066029A1 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015041765A1 (en) * 2013-09-20 2015-03-26 Cirrus Logic, Inc. Systems and methods for protecting a speaker from overexcursion
EP2879404A1 (de) * 2013-12-02 2015-06-03 BlackBerry Limited Rückseitenhohlraum-Mikrofonimplementierung
EP2966878A1 (de) * 2014-07-10 2016-01-13 Nxp B.V. System zur steuerung der verlagerung eines lautsprechers
CN107135456A (zh) * 2017-04-27 2017-09-05 歌尔丹拿音响有限公司 音箱漏气检测装置和方法、计算机可读存储介质
US9967404B2 (en) 2015-05-28 2018-05-08 Nxp B.V. Echo controller

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10341768B2 (en) 2016-12-01 2019-07-02 Cirrus Logic, Inc. Speaker adaptation with voltage-to-excursion conversion
TW201913642A (zh) * 2017-09-05 2019-04-01 美律實業股份有限公司 聲學傳感裝置
CN108282725B (zh) * 2018-02-14 2024-01-16 钰太芯微电子科技（上海）有限公司 一种集成背腔压力感知的扩音系统及音频播放器
CN112637752B (zh) * 2020-12-30 2022-08-16 武汉市聚芯微电子有限责任公司 扬声器共振频率与环境气压的简易关联监测方法及系统

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090028371A1 (en) * 2006-03-06 2009-01-29 General Innovations, Inc. Positionally Sequenced Loudspeaker System
US20100172516A1 (en) * 2006-08-10 2010-07-08 Claudio Lastrucci To systems for acoustic diffusion

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090028371A1 (en) * 2006-03-06 2009-01-29 General Innovations, Inc. Positionally Sequenced Loudspeaker System
US20100172516A1 (en) * 2006-08-10 2010-07-08 Claudio Lastrucci To systems for acoustic diffusion

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015041765A1 (en) * 2013-09-20 2015-03-26 Cirrus Logic, Inc. Systems and methods for protecting a speaker from overexcursion
KR20160060098A (ko) * 2013-09-20 2016-05-27 씨러스 로직 인코포레이티드 오버익스커션으로부터 스피커를 보호하기 위한 시스템들 및 방법들
CN105745943A (zh) * 2013-09-20 2016-07-06 美国思睿逻辑有限公司 用于防止扬声器过度偏移的系统及方法
US9432771B2 (en) 2013-09-20 2016-08-30 Cirrus Logic, Inc. Systems and methods for protecting a speaker from overexcursion
CN105745943B (zh) * 2013-09-20 2019-04-02 美国思睿逻辑有限公司 用于防止扬声器过度偏移的系统及方法
EP2879404A1 (de) * 2013-12-02 2015-06-03 BlackBerry Limited Rückseitenhohlraum-Mikrofonimplementierung
US9432762B2 (en) 2013-12-02 2016-08-30 Blackberry Limited Back cavity microphone implementation
EP2966878A1 (de) * 2014-07-10 2016-01-13 Nxp B.V. System zur steuerung der verlagerung eines lautsprechers
US9374634B2 (en) 2014-07-10 2016-06-21 Nxp B.V. System for controlling displacement of a loudspeaker
US9967404B2 (en) 2015-05-28 2018-05-08 Nxp B.V. Echo controller
CN107135456A (zh) * 2017-04-27 2017-09-05 歌尔丹拿音响有限公司 音箱漏气检测装置和方法、计算机可读存储介质
CN107135456B (zh) * 2017-04-27 2020-12-08 歌尔智能科技有限公司 音箱漏气检测装置和方法、计算机可读存储介质

Also Published As

Publication number Publication date
WO2012066029A1 (en) 2012-05-24

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