EP0477591A1 - Amplificateur - Google Patents

Amplificateur Download PDF

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Publication number
EP0477591A1
EP0477591A1 EP91114737A EP91114737A EP0477591A1 EP 0477591 A1 EP0477591 A1 EP 0477591A1 EP 91114737 A EP91114737 A EP 91114737A EP 91114737 A EP91114737 A EP 91114737A EP 0477591 A1 EP0477591 A1 EP 0477591A1
Authority
EP
European Patent Office
Prior art keywords
amplifier
circuit
loudspeaker
unit
characteristic
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
EP91114737A
Other languages
German (de)
English (en)
Other versions
EP0477591B1 (fr
Inventor
Roger Schultheiss
Paul Zwicky
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.)
Harman International Industries Inc
Original Assignee
Studer Professional Audio AG
Studer Revox AG
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 Studer Professional Audio AG, Studer Revox AG filed Critical Studer Professional Audio AG
Publication of EP0477591A1 publication Critical patent/EP0477591A1/fr
Application granted granted Critical
Publication of EP0477591B1 publication Critical patent/EP0477591B1/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
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/04—Circuits for transducers, loudspeakers or microphones for correcting frequency response

Definitions

  • the invention relates to an amplifier unit for feeding an electrodynamic loudspeaker unit, which is arranged in a housing together with a device which is coupled to the loudspeaker unit and adds the sound energy in a limited frequency range to the same energy as that which is emitted from the front of the loudspeaker unit.
  • bass reflex housings with amplifier units which are provided for supplying the loudspeaker units arranged in the bass reflex housing.
  • two resonance circuits are usually coupled to one another.
  • One resonant circuit is represented by the loudspeaker unit and the other resonant circuit is represented by the above-mentioned device, this device consisting, for example, of an opening in the housing which is coupled via the air in the housing to the back of the membrane of the loudspeaker unit.
  • Such bass reflex housings usually offer acoustic support in a narrowly limited frequency range. It is from the Journal of the Audio Engineering Society, Vol. 19, No. 6, June 1971, A.N. Thiele: "Loudspeakers in Vented Boxes: Part II" known to feed such loudspeaker units with an amplifier with negative output impedance, which improves the adaptation of the loudspeaker unit to their housing and vice versa.
  • Another such amplifier unit for feeding the voice coil of a bass speaker is known for example from DE-OS-27 13 023.
  • the amplifier unit has an output impedance that is equivalent to a negative resistance that is in series with a parallel resonant circuit.
  • the negative resistance has practically the same value as the resistance of the voice coil.
  • a loudspeaker system is known from EP 0 322 679, in which a membrane drives a first resonator with its front side and a second resonator with its rear side and thus does not produce any sound acting directly to the outside. Compared to a system with a single resonator, the frequency range in which resonance and thus bass amplification occur can thus be expanded. By feeding such a system with an amplifier with negative output impedance, the frequency response for low frequencies can be improved.
  • the invention as characterized in the claims solves the problem of creating an amplifier unit which is as ideal as possible from the bass range to the high frequency range, i.e. straight frequency and phase response without having to do without the acoustic support of a housing resonator.
  • the advantages achieved by the invention can be seen in particular in the fact that the amplifier unit according to the invention can be connected very well with a loudspeaker which is installed in a housing which has a Helmholtz resonator or any other vibratable element, such as for example for so-called bass reflex boxes apply. Due to the special design of the amplifier unit, the advantages that a negative output impedance offers at the amplifier unit can be combined with the advantages that, for example, bass reflex systems offer.
  • FIG. 10 shows a further exemplary embodiment of the circuit 7.
  • the input 12 is connected via a line 49 in series with a first differentiator 50, a first adder 51, a node 52, a second differentiator 53, a second adder 54, an integrator 55 and an First-order low-pass filter 56 connected to output 18.
  • a further line 57 leads from the input 12 to the first adder 51 and from the node 52 a further line 58 to the second adder 54.
  • This circuit is mathematically represented by the formula shown.
  • the exemplary embodiments for the circuit 7, as shown in FIGS. 7 to 12, are thus relatively simple filters which the person skilled in the art can easily replicate. Therefore they are not described further. It is also clear to the person skilled in the art that an integrator can also be designed as a low-pass filter or can be understood as such. Correspondingly, two successive first-order low-pass filters can then also be designed as a second-order low-pass filter. The same also applies to differentiators, which can be designed as high-pass filters.
  • FIG. 11 shows a representation of a frequency response 59 as it applies to a bass reflex loudspeaker known per se.
  • frequency values are plotted logarithmically in Hertz.
  • values for amplitudes are plotted in decibels.
  • 3dB point which is labeled 62. This means that the amplitude of a signal with a frequency of 40Hz is reduced by 3dB compared to the amplitude of a signal with a multiple frequency.
  • FIG. 12 shows a representation of the phase shift 63 for signals which are reproduced in the above-mentioned bass reflex loudspeaker.
  • the frequency along a horizontal 64, as in FIG. 11, and along a vertical 65 values for the phase difference from 0 ° to 360 ° are given.
  • FIG. 13 shows a representation of the transit times 66 of signals with different frequencies in the above-mentioned bass reflex loudspeaker. For this purpose, 67 values of frequencies are plotted along a horizontal line and 68 values of times or time differences in seconds along a vertical line. For example, you can see from this that a signal with a frequency of 40Hz is delayed by approx. 0.015 sec.
  • FIG. 14 shows, corresponding to FIG. 11, a representation of a frequency response 69 for a housing with a Helmholtz resonator and with a loudspeaker unit which is connected to an amplifier with a negative output impedance. It can be seen that maximum amplitudes are achieved at a frequency of 40 Hz.
  • FIG. 15 shows, corresponding to FIG. 12, a representation of the phase shift 70 for signals originating from a loudspeaker unit with a housing, as is the case for FIG. 14.
  • FIG. 16 shows, corresponding to FIG. 13, a representation of the transit times 71 of signals with different frequencies as they originate from a loudspeaker unit with a housing, as is the case with the Figures 14 and 15 applies. You can see here that for this example the longest running time for a signal with approx. 40 Hz applies.
  • FIGS. 17, 18 and 19 show characteristics as they apply to a circuit 7 for changing the characteristics of the output signal.
  • FIGS. 11, 12 and 13 show characteristics according to the prior art
  • FIGS. 14, 15 and 16 show characteristics for a combination of a loudspeaker unit with a bass reflex housing and an amplifier with a negative output impedance, which is not part of the prior art because it was never executed.
  • This combination represents only one step in the development of the solution according to the invention, which is shown here for better understanding, but was never actually made because it has serious errors in the frequency response, phase response and timing.
  • FIG. 17 shows as a characteristic a frequency response 72 which is inverse to the frequency response 69 from FIG. 14. It is plotted above a horizontal 60 or next to a vertical 61, along which the frequency values or amplitude values are plotted, as is already the case for FIGS. 11 and 14.
  • FIG. 18 shows as a characteristic a representation of the phase shift 73, which is inverse to the representation of the phase shift in FIG. 15.
  • the values for the frequencies along the horizontal 64 are the same as in FIG. 15 and the values for the phase shift along the vertical 65 extend from 0 ° to -150 °.
  • FIG. 19 shows as a characteristic a representation of the transit times 74, which is inverse to the corresponding representation 71 in FIG. 16. The same values for the frequencies along the horizontal 67 and the same values for the transit times along the vertical 68 are plotted.
  • FIG. 20 shows an equivalent circuit 75 for the amplifier unit 1 together with the loudspeaker unit 2, the housing 3 and the device 5 as shown in FIG. 1.
  • the equivalent circuit 75 is a motion equivalent circuit. In it, electrical voltages correspond to the movements or speeds, for example the membrane of the loudspeaker unit or the air that is moved through it.
  • the equivalent circuit 75 has been simplified in a known manner in that the acoustic part and the mechanical part of a general equivalent circuit known from the publications mentioned have both been included in the electrical part. Accordingly, only a generator 76 can be seen therein, which is connected in series via a line 77 with resistors 78 and 79, with an inductor 80 and with a capacitor 81. Arranged in between and connected in parallel with the generator 76 with the resistors 78, 79 are also each a capacitor 82, an inductor 83 and a resistor 84.
  • the resistor 78 corresponds to the internal resistance of the generator 76
  • the resistor 79 corresponds to the voice coil resistance in the loudspeaker unit
  • the inductance 80 the acoustic mobility of the air cushion in the housing or the reciprocal of the acoustic spring constants of the air behind the membrane
  • the capacity 81 the acoustic mass of the air column in the tube of the Helmholtz resonator
  • the capacity 82 all other masses of the system added together (excluding the masses already mentioned above)
  • the inductance 83 the sum of the other mobilities or the reciprocal of all mechanical and acoustic spring forces in the system
  • the resistance 84 the sum of the reciprocal of the losses (mechanical friction, heating etc.) in the system, including radiation impedances of the membrane .
  • a resistor 85 which corresponds to the reciprocal of the acoustic losses, including radiation impedances in the Helmholtz resonator, is also connected in parallel with the capacitance 81.
  • the sum of the resistances in the resistors 78 and 79 must be zero.
  • circuits 7 for changing the output signal as shown in FIGS. 5 to 10 change an input signal as it is input at input 6 or 12, in accordance with the characteristics 72, 73, 74 as shown in FIGS. 19, 20, 21 show.
  • the signal modified in this way is then fed to the integrator 8 where it is integrated over time.
  • the frequency response of such an integrator is known per se and corresponds to a line falling with increasing frequency, with a logarithmic representation of the frequency.
  • the signal is then fed to the amplifier 9, which amplifies it and gives the signal the characteristic of a negative impedance.
  • the frequency response of this amplifier 9 together with the downstream loudspeaker unit with housing is inverse to the frequency response of the integrator 8, which is why it is connected upstream.
  • the signal emitted in total by the housing 3 then again has an ideal frequency response.
  • the characteristic over all elements of the amplifier unit 1, with the exception of the circuit 7, and of the loudspeaker is determined and compared with the ideal characteristic. This creates characteristics 69, 70, 71.
  • straight characteristics, inverse characteristics 72, 73, 74 are generated. This already compensates for interference that occurs in the loudspeaker unit 2.
  • the negative impedance must be able to have an undisturbed effect over as wide a frequency range as possible, for example at least up to two octaves above the resonance frequency of the loudspeaker unit.
  • the transfer function for a circuit 7 can then easily be derived from the above-mentioned transfer function, which is derived from the equivalent circuit 75 with a negative output impedance for the generator 76. It corresponds to the inverse transfer function and is:
  • circuit 7 for changing the characteristics of the output signal can be constructed using known digitally working means, and thus the characteristics can also be generated digitally.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Circuit For Audible Band Transducer (AREA)
  • Amplifiers (AREA)
  • Lubrication Of Internal Combustion Engines (AREA)
EP91114737A 1990-09-27 1991-09-02 Amplificateur Expired - Lifetime EP0477591B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH311190 1990-09-27
CH3111/90 1990-09-27

Publications (2)

Publication Number Publication Date
EP0477591A1 true EP0477591A1 (fr) 1992-04-01
EP0477591B1 EP0477591B1 (fr) 1995-06-28

Family

ID=4248857

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91114737A Expired - Lifetime EP0477591B1 (fr) 1990-09-27 1991-09-02 Amplificateur

Country Status (5)

Country Link
US (1) US5181251A (fr)
EP (1) EP0477591B1 (fr)
AT (1) ATE124596T1 (fr)
DE (1) DE59105848D1 (fr)
DK (1) DK0477591T3 (fr)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2056110C (fr) * 1991-03-27 1997-02-04 Arnold I. Klayman Dispositif pour ameliorer l'intelligibilite dans les systemes de sonorisation
DE4111884A1 (de) * 1991-04-09 1992-10-15 Klippel Wolfgang Schaltungsanordnung zur korrektur des linearen und nichtlinearen uebertragungsverhaltens elektroakustischer wandler
US5542001A (en) * 1994-12-06 1996-07-30 Reiffin; Martin Smart amplifier for loudspeaker motional feedback derived from linearization of a nonlinear motion responsive signal
US6269318B1 (en) * 1997-04-30 2001-07-31 Earl R. Geddes Method for determining transducer linear operational parameters
US6993480B1 (en) 1998-11-03 2006-01-31 Srs Labs, Inc. Voice intelligibility enhancement system
US20030142875A1 (en) * 1999-02-04 2003-07-31 Goertzen Kenbe D. Quality priority
US20030185455A1 (en) * 1999-02-04 2003-10-02 Goertzen Kenbe D. Digital image processor
JP2001169384A (ja) * 1999-12-10 2001-06-22 Pioneer Electronic Corp スピーカシステム
CA2404861A1 (fr) * 2000-02-02 2001-08-09 Quvis, Inc. Systeme et procede permettant d'optimiser une resolution d'image au moyen de dispositifs d'imagerie pixelises
CA2408045A1 (fr) * 2001-10-16 2003-04-16 Audio Products International Corp. Haut-parleur a asservissement a grand deplacement
DE102004021546A1 (de) * 2004-05-03 2005-12-08 Avantgarde Acoustic Lautsprechersysteme Gmbh Hornlautsprecher
DE602005019435D1 (de) * 2005-12-14 2010-04-01 Harman Becker Automotive Sys Verfahren und Vorrichtung zum Vorhersehen des Verhaltens eines Wandlers
JP4785650B2 (ja) * 2006-06-30 2011-10-05 キヤノン株式会社 音声信号処理装置および音声信号処理方法
US8050434B1 (en) 2006-12-21 2011-11-01 Srs Labs, Inc. Multi-channel audio enhancement system

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0334217A2 (fr) * 1988-03-25 1989-09-27 Yamaha Corporation Méthode et appareil pour l'expansion de la gamme sonore reproduite

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE398287B (sv) * 1976-03-24 1977-12-12 Stahl Karl Erik Forfarande for forbettring av ett elektrodynamiskt hogtalarelements basatergivning, samt anordning for utforande av forfarandet
NL8501719A (nl) * 1985-06-14 1987-01-02 Philips Nv Basreflex luidsprekersysteem.
JP2701279B2 (ja) * 1987-12-28 1998-01-21 ヤマハ株式会社 音響装置
JPH0728473B2 (ja) * 1988-05-06 1995-03-29 ヤマハ株式会社 インピーダンス補償回路
US5014320A (en) * 1988-05-25 1991-05-07 Yamaha Corporation Driving apparatus, and control information storage body and protection circuit therefor
US5031500A (en) * 1988-06-21 1991-07-16 Yamaha Corporation Keyboard instrument

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0334217A2 (fr) * 1988-03-25 1989-09-27 Yamaha Corporation Méthode et appareil pour l'expansion de la gamme sonore reproduite

Also Published As

Publication number Publication date
ATE124596T1 (de) 1995-07-15
EP0477591B1 (fr) 1995-06-28
DK0477591T3 (da) 1995-08-28
DE59105848D1 (de) 1995-08-03
US5181251A (en) 1993-01-19

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