EP1684543A1 - Procédé à l'affaiblissement de rétroaction électro-acoustique - Google Patents

Procédé à l'affaiblissement de rétroaction électro-acoustique Download PDF

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Publication number
EP1684543A1
EP1684543A1 EP05001063A EP05001063A EP1684543A1 EP 1684543 A1 EP1684543 A1 EP 1684543A1 EP 05001063 A EP05001063 A EP 05001063A EP 05001063 A EP05001063 A EP 05001063A EP 1684543 A1 EP1684543 A1 EP 1684543A1
Authority
EP
European Patent Office
Prior art keywords
frequency
level
feedback
microphone signal
microphone
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Withdrawn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
EP05001063A
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German (de)
English (en)
Inventor
Martin Börsch
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.)
Success Chip Ltd
Original Assignee
Success Chip 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 Success Chip Ltd filed Critical Success Chip Ltd
Priority to EP05001063A priority Critical patent/EP1684543A1/fr
Priority to US11/052,398 priority patent/US20060159282A1/en
Priority to CN200510008816.XA priority patent/CN1809220A/zh
Publication of EP1684543A1 publication Critical patent/EP1684543A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • H04R3/02—Circuits for transducers, loudspeakers or microphones for preventing acoustic reaction, i.e. acoustic oscillatory feedback
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R27/00—Public address systems

Definitions

  • the invention relates to a method for suppressing electro-acoustic feedback in an audio system comprising a microphone which drives a loudspeaker system via an amplifier, in particular in the context of a public address system in accordance with the preamble of claim 1.
  • the invention is in the field of electroacoustic performances, such as live music events.
  • PA systems with microphones are used, with which voices and instruments are detected electroacoustically, amplified and played back via loudspeakers.
  • This can lead to feedback of the amplified microphone signal over the range microphone amplifier that produce unpleasant loud sound events on the speakers.
  • these feedbacks also referred to as feedback, when the detected by the microphone speaker sound signal passes in phase to the microphone payload the distance microphone amplifier.
  • these signals can increasingly rock and generate loud and high sound amplitudes through the loudspeakers at a typical feedback frequency that changes over time.
  • a previous countermeasure in terms of feedback effects provides to turn off the PA system or at least drastically reduce their gain.
  • the generic method mentioned at the outset which proceeds in the time domain in the prior art, runs in the frequency range in which the microphone signal is converted by a fast Fourier transformation.
  • that frequency is rated as a feedback frequency at which the maximum level of the microphone signal exceeds the threshold value in the form of a predetermined ratio of the maximum level of the microphone signal to the overall level of the microphone signal.
  • the microphone signal is provided before the steps of the generic method by all-pass filtering in combination with the fast Fourier transform (FFT) of the time domain in a "bark" scaled frequency range transform.
  • FFT fast Fourier transform
  • the filtering out of the feedback frequency is narrow band, especially by means of a notch filter, which can be realized with a bandwidth of 1/60 octave and does not affect the Audionutzsignal by its use according to the invention.
  • correction procedures for frequency and level are proposed according to the invention, which can be implemented in real time without loss of time.
  • FIG. 1 shows a PA system typically used in live events, comprising a microphone 1 whose microphone signal is fed via a mixer 2 into a power amplifier 3 which drives a loudspeaker 4 with the amplified microphone signal.
  • a microphone 1 whose microphone signal is fed via a mixer 2 into a power amplifier 3 which drives a loudspeaker 4 with the amplified microphone signal.
  • the z. B. is used by an instrumentalist or singer, in-phase fed into the amplifier and then emitted by the speaker. This loop is indicated in Fig. 1 with a circular arrow.
  • the formation of a feedback in the feedback loop is inhibited by detecting the level of the microphone signal on the microphone amplifier path, the readiness for the occurrence of a feedback being detected by the fact that the level of the microphone signal exceeds a threshold value.
  • the frequency of the microphone signal at this critical level is evaluated as a feedback frequency and filtered out of the microphone signal to suppress feedback by means of a narrow band filter such as the notch filter whose frequency characteristic is shown in FIG.
  • the microphone signal is transformed from the time domain to the frequency domain by a combination of a network of all-pass filters and a fast Fourier transform (FFT).
  • FFT fast Fourier transform
  • the level maximum is determined and subjected to error correction by means of two adjacent frequency values (FIG. 3). Once this level reaches a predetermined ratio of the overall level of the microphone signal (a threshold set thereby), the frequency at which that level occurs is rated as the feedback frequency and filtered out of the frequency spectrum by a narrow band filter. If necessary, a filter already existing in the vicinity of this frequency can be shifted to the position of this frequency and brought into effect.
  • Fig. 3 shows the measured energy of some frequency pots.
  • the correction of the maximum level is carried out in accordance with Fig. 4 via a tabular correction value k, which is anti-proportional to the value of the difference "peakdiff" of the maximum level at the frequency f (x) to the adjacent level at the frequency f (x + 1) ,
  • the smaller the difference ("peakdiff", the larger the factor k and thus also the level correction value ⁇ p k (peakdiff).
  • the filter frequency of the notch filter (FIG. 2) is preferably continuously updated accordingly.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Circuit For Audible Band Transducer (AREA)
EP05001063A 2005-01-19 2005-01-19 Procédé à l'affaiblissement de rétroaction électro-acoustique Withdrawn EP1684543A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP05001063A EP1684543A1 (fr) 2005-01-19 2005-01-19 Procédé à l'affaiblissement de rétroaction électro-acoustique
US11/052,398 US20060159282A1 (en) 2005-01-19 2005-02-07 Method for suppressing electroacoustic feedback
CN200510008816.XA CN1809220A (zh) 2005-01-19 2005-02-23 抑制电声反馈的方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP05001063A EP1684543A1 (fr) 2005-01-19 2005-01-19 Procédé à l'affaiblissement de rétroaction électro-acoustique

Publications (1)

Publication Number Publication Date
EP1684543A1 true EP1684543A1 (fr) 2006-07-26

Family

ID=34933375

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05001063A Withdrawn EP1684543A1 (fr) 2005-01-19 2005-01-19 Procédé à l'affaiblissement de rétroaction électro-acoustique

Country Status (3)

Country Link
US (1) US20060159282A1 (fr)
EP (1) EP1684543A1 (fr)
CN (1) CN1809220A (fr)

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US7664275B2 (en) * 2005-07-22 2010-02-16 Gables Engineering, Inc. Acoustic feedback cancellation system
US20070104335A1 (en) * 2005-11-09 2007-05-10 Gpe International Limited Acoustic feedback suppression for audio amplification systems
JP4697267B2 (ja) * 2008-07-01 2011-06-08 ソニー株式会社 ハウリング検出装置およびハウリング検出方法
KR101671389B1 (ko) * 2010-03-05 2016-11-01 삼성전자 주식회사 가변 대역 폭 적응 노치 필터, 및 가변 대역 폭 적응 노치 필터를 이용하여 하울링을 제거하는 방법 및 장치
US8908877B2 (en) 2010-12-03 2014-12-09 Cirrus Logic, Inc. Ear-coupling detection and adjustment of adaptive response in noise-canceling in personal audio devices
JP5937611B2 (ja) 2010-12-03 2016-06-22 シラス ロジック、インコーポレイテッド パーソナルオーディオデバイスにおける適応ノイズキャンセラの監視制御
US9318094B2 (en) 2011-06-03 2016-04-19 Cirrus Logic, Inc. Adaptive noise canceling architecture for a personal audio device
US8948407B2 (en) 2011-06-03 2015-02-03 Cirrus Logic, Inc. Bandlimiting anti-noise in personal audio devices having adaptive noise cancellation (ANC)
US8958571B2 (en) 2011-06-03 2015-02-17 Cirrus Logic, Inc. MIC covering detection in personal audio devices
US9824677B2 (en) 2011-06-03 2017-11-21 Cirrus Logic, Inc. Bandlimiting anti-noise in personal audio devices having adaptive noise cancellation (ANC)
US9325821B1 (en) 2011-09-30 2016-04-26 Cirrus Logic, Inc. Sidetone management in an adaptive noise canceling (ANC) system including secondary path modeling
US9319781B2 (en) 2012-05-10 2016-04-19 Cirrus Logic, Inc. Frequency and direction-dependent ambient sound handling in personal audio devices having adaptive noise cancellation (ANC)
US9318090B2 (en) 2012-05-10 2016-04-19 Cirrus Logic, Inc. Downlink tone detection and adaptation of a secondary path response model in an adaptive noise canceling system
US9123321B2 (en) 2012-05-10 2015-09-01 Cirrus Logic, Inc. Sequenced adaptation of anti-noise generator response and secondary path response in an adaptive noise canceling system
US9532139B1 (en) 2012-09-14 2016-12-27 Cirrus Logic, Inc. Dual-microphone frequency amplitude response self-calibration
US9369798B1 (en) 2013-03-12 2016-06-14 Cirrus Logic, Inc. Internal dynamic range control in an adaptive noise cancellation (ANC) system
US9414150B2 (en) 2013-03-14 2016-08-09 Cirrus Logic, Inc. Low-latency multi-driver adaptive noise canceling (ANC) system for a personal audio device
US9502020B1 (en) * 2013-03-15 2016-11-22 Cirrus Logic, Inc. Robust adaptive noise canceling (ANC) in a personal audio device
US9578432B1 (en) 2013-04-24 2017-02-21 Cirrus Logic, Inc. Metric and tool to evaluate secondary path design in adaptive noise cancellation systems
US9369557B2 (en) 2014-03-05 2016-06-14 Cirrus Logic, Inc. Frequency-dependent sidetone calibration
US9319784B2 (en) 2014-04-14 2016-04-19 Cirrus Logic, Inc. Frequency-shaped noise-based adaptation of secondary path adaptive response in noise-canceling personal audio devices
CN105007552A (zh) * 2015-06-10 2015-10-28 深圳市信太通讯有限公司 一种高保真音频系统
US10026388B2 (en) 2015-08-20 2018-07-17 Cirrus Logic, Inc. Feedback adaptive noise cancellation (ANC) controller and method having a feedback response partially provided by a fixed-response filter
US10540983B2 (en) 2017-06-01 2020-01-21 Sorenson Ip Holdings, Llc Detecting and reducing feedback
CN109905811B (zh) * 2019-01-24 2021-02-26 珠海慧联科技有限公司 一种经济型声反馈控制的方法及装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3183304A (en) * 1962-03-07 1965-05-11 Bell Telephone Labor Inc Sound amplification system
US4232192A (en) * 1978-05-01 1980-11-04 Starkey Labs, Inc. Moving-average notch filter
EP0599450A2 (fr) * 1992-11-25 1994-06-01 Matsushita Electric Industrial Co., Ltd. Dispositif d'amplification de son avec suppression automatique de réaction acoustique
US5677987A (en) * 1993-11-19 1997-10-14 Matsushita Electric Industrial Co., Ltd. Feedback detector and suppressor
WO2003036621A1 (fr) * 2001-10-22 2003-05-01 Motorola, Inc., A Corporation Of The State Of Delaware Procede et appareil permettant d'ameliorer la sonie d'un signal audio

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US3257510A (en) * 1962-10-15 1966-06-21 Industrial Res Prod Inc Feedback control apparatus
US4088835A (en) * 1977-02-07 1978-05-09 Rauland-Borg Corporation Comprehensive feedback elimination system employing notch filter
JP3152160B2 (ja) * 1996-11-13 2001-04-03 ヤマハ株式会社 ハウリング検出防止回路及びそれを用いた拡声装置
JP3984842B2 (ja) * 2002-03-12 2007-10-03 松下電器産業株式会社 ハウリング制御装置
US7536022B2 (en) * 2002-10-02 2009-05-19 Phonak Ag Method to determine a feedback threshold in a hearing device
US7664275B2 (en) * 2005-07-22 2010-02-16 Gables Engineering, Inc. Acoustic feedback cancellation system
US20070104335A1 (en) * 2005-11-09 2007-05-10 Gpe International Limited Acoustic feedback suppression for audio amplification systems

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3183304A (en) * 1962-03-07 1965-05-11 Bell Telephone Labor Inc Sound amplification system
US4232192A (en) * 1978-05-01 1980-11-04 Starkey Labs, Inc. Moving-average notch filter
EP0599450A2 (fr) * 1992-11-25 1994-06-01 Matsushita Electric Industrial Co., Ltd. Dispositif d'amplification de son avec suppression automatique de réaction acoustique
US5677987A (en) * 1993-11-19 1997-10-14 Matsushita Electric Industrial Co., Ltd. Feedback detector and suppressor
WO2003036621A1 (fr) * 2001-10-22 2003-05-01 Motorola, Inc., A Corporation Of The State Of Delaware Procede et appareil permettant d'ameliorer la sonie d'un signal audio

Also Published As

Publication number Publication date
US20060159282A1 (en) 2006-07-20
CN1809220A (zh) 2006-07-26

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