EP1084589B1 - Druckluftgetriebener lautsprecher und dessen verwendung - Google Patents

Druckluftgetriebener lautsprecher und dessen verwendung Download PDF

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Publication number
EP1084589B1
EP1084589B1 EP99925504A EP99925504A EP1084589B1 EP 1084589 B1 EP1084589 B1 EP 1084589B1 EP 99925504 A EP99925504 A EP 99925504A EP 99925504 A EP99925504 A EP 99925504A EP 1084589 B1 EP1084589 B1 EP 1084589B1
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EP
European Patent Office
Prior art keywords
loudspeaker
tube
chamber
surroundings
openings
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EP99925504A
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English (en)
French (fr)
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EP1084589A1 (de
Inventor
Per-Arne Wiberg
Urban Emborg
Sohan Sarin
Joakim Holmgren
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A2 Acoustics AB
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A2 Acoustics AB
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K7/00—Sirens

Definitions

  • the invention presented here concerns a pneumatically driven loudspeaker comprising at least one chamber having higher pressure than the surroundings and at least one chamber with lower pressure than the surroundings, as well as a modulatable opening between the respective chambers and the surroundings.
  • Pneumatically driven loudspeakers are previously known. These loudspeakers comprise a chamber with positive pressure as well as several openings in one wall of the chamber. Over these openings is a slide which can move in such a way that it in one setting closes the openings and in another setting opens them. By moving the slide back and forth with a certain frequency a sound wave of corresponding frequency is obtained by the pulsating emission of compressed air through the openings.
  • Pneumatic loudspeakers have the advantage over other known types of loudspeaker in that they give a high output at the same time as they take up relatively little space. This makes them especially suitable for use in active noise suppression etc.
  • Factors contributing to the strong non-linearity in the said type of known pneumatic loudspeaker is that the positive pressure presses the slide against the bracket in which it slides, which causes friction. Furthermore, the intermittently emitted airflow displays a markedly asymmetrical wave characteristic because of the non-linearity.
  • GB-A-2 033 130 discloses a pneumatically driven loudspeaker according to the preamble of claim 1.
  • the known loudspeaker comprises a first chamber having higher pressure than the surroundings where the first chamber has a first opening, and a second chamber with lower pressure than the surroundings where this second chamber has a second opening.
  • the first and second openings are not directly connected to the surroundings but connected to a resonator tube.
  • a spring-biased valve mechanism is provided, wherein the first and second openings by means of the valve mechanism alternately open and close at a frequency determined by the frequency of the resonator tube.
  • FR-A-2 729 781 discloses a device for active noise reduction.
  • the device includes a pneumatic loudspeaker which is driven in a conventional manner.
  • a pneumatically driven loudspeaker comprising at least one chamber having higher pressure than the surroundings and at least one chamber with lower pressure than the surroundings.
  • the chambers are each supplied with at least one modulatable opening to the surroundings, making it possible to alternately open and close the high pressure and low pressure chambers to the surroundings by means of a valve mechanism, which means for example that the opening to the high pressure chamber is opened while the opening to the low pressure chamber is closed and vice versa.
  • This modulation of the opening proceeds at the frequency selected.
  • the loudpeaker's efficiency and output can be increased.
  • surroundings is understood to mean the environment in which the loudspeaker is operating, which normally means that the surroundings is the air space around the loudspeaker, so that the surroundings are at atmospheric pressure. Other ambient pressures are naturally possible.
  • the air is alternately pressed out from and sucked back into the loudspeaker.
  • an exhaust characteristic with an essentially inverted suction characteristic. Both these curves are strongly non-linear, but with the superposing a greater symmetry is achieved in the characteristic.
  • the loudspeaker produces a less distorted signal and is therefore easier to control compared to if only one chamber with pressure differing from the surroundings is used.
  • the invention is especially suitable for use in active noise suppression because of its high output per weight and area unit, as well as being able to operate within a wide range of frequencies.
  • Fig 1A shows schematically a loudspeaker cell according to an embodiment of the invention presented here.
  • the loudspeaker comprises at least one chamber, preferably several chambers 1.2 with alternating positive and negative pressure stacked one on the other in a sandwich-like construction. Through the openings in these chamber walls a sliding tube 3 is fitted. This tube is preferably open at both ends. Moreover, the tube has at least one set of openings 4 at essentially the same height in the tube's envelope surface. In this way, when the openings are within the positive pressure chamber 1, air will flow in through the openings 4, continue along the tube 3 and out through the opening at the end.
  • the tube When the tube is slid so that the openings instead end up in the negative pressure chamber 2 air is instead sucked into the chamber from the end opening via the tube.
  • air By sliding the tube to and fro at a certain frequency a pulsating air wave is produced, and from this a sound is generated.
  • the chambers can instead be arranged in sectors around the tube, so that the the tube makes a radial motion instead on an axial one. Even in this case. however. the motion is to and fro.
  • the frequency of the sound can be increased since the side openings 4 in the tube pass several positive and negative pressure chambers during each stroke.
  • the tube is , however, best furnished with several sets of side openings.
  • the number of such sets of side openings is preferably the same as the number of chambers with positive pressure or chambers with negative pressure.
  • the sets of side openings are preferably arranged vertically, that is to say in the direction of the axis of the tube, and separated so that each opening is either in the positive pressure chamber or negative pressure chamber.
  • the tube is operated by a driving mechanism, which can be hydraulic, pneumatic or thermally generated.
  • the preferred mode is electromagnetic by means of a coil wound round the lower end of the tube.
  • the piezo-electric drive can even have some form of gear so as to efficiently obtain a low frequency, which is often desirable since piezo-electric cells often operate at a higher frequency (usually about 50-100 kHz), while the loudspeaker is normally used at considerably lower frequencies.
  • An advantage of the piezo-electric drive is that the construction is very small and light, while the motion. i.e. the stroke lengths, of the modulatable openings is decreased. This results in both reduced friction between fixed and moving parts and lower distortion.
  • Fig. 18 shows a preferred type of piezo-electric drive mechanism.
  • a rod 6 which is fixed to the frame and is inserted into the tube 3.
  • arms 7, which at their other extremities are attached to the inner wall of the tube 3.
  • These arms are piezo-electric bending cells, which when activated produce an axial motion of the tube.
  • these bending cells can even be arranged in other ways. For example, several rods can be used, so that the bending cells extend in directions that intersect one another, or the rod can be placed in the centre from which the arms extend radially in different directions.
  • the loudspeaker comprises pneumatic drive devices (not shown) for producing positive and negative pressure in the chambers.
  • pneumatic drive devices can be conventional pumps or fans, for example.
  • the chambers can even be connected to available compressed-air systems.
  • the tube is preferably circular and preferably fits relatively tightly into the corresponding openings in the chamber walls.
  • the side openings are preferably symmetrically placed, such as two openings opposite one another, or four openings arranged in a cross. In that way the resulting force which the pressure in the chambers has on the tube is essentially zero. so that the friction between the tube and the chamber walls is reduced and the tube slides more easily. As a result, the distortion is reduced in the loudspeaker and it is easier to control.
  • the tube can naturally have a cross sectional shape other than circular, for example elliptical, quadratic, rectangular, etc.
  • a tube 3 as described above it should be made shorter for generation of higher frequencies. If the tube is long a sound wave generated at the bottom of the tube will interfere with a sound wave generated at the top of the tube. This becomes a problem only if the length of the tube is of the same order of magnitude as the length of the sound wave at a specific frequency. This can be prevented if the tube is designed as a number of rings which constitute the active components of the valve body. The rings are connected to each other by means of circular springs in such a way that the rings perform a translation motion along the length of the tube at the speed of sound. The said undesired interference will not manifest itself. while energy will be supplied to the generated sound wave for each ring. At one end of the tube the change is passively or actively suppressed so that no reverberations of the wave motion arise.
  • Fig 6a-6c shows a loudspeaker which is also designed to generate acoustic pressure at a certain frequency of choice.
  • This version comprises a space 60 for fluctuating pressure, acoustic pressure, where the said space 60 is in contact with the surrounding air in which it is intended to produce acoustic pressure.
  • a valve mechanism in the form of a rotating alve body 65 located in the space 60 for the fluctuating pressure alternately opens the openings 61 and 63 to the high pressure chamber 62 and low-pressure chamber 64 respectively, whereby the desired acoustic pressure is generated in the space 60.
  • the generated acoustic pressure is directed to the surroundings through the opening 66.
  • the valve body 65 is rotated at a selected number of revolutions, which means that the frequency of the generated sound can be varied by adjusting the valve body's 65 rate of rotation.
  • the valve body 65 can be designed in an alternative way according to the figures 6a, 6b, and 6c.
  • Characteristic for this version of the invention is that the valve body is made up of a rotation unit, where a part of the rotation unit consists of a cavity 67.
  • the cavity when facing the opening 61 to the high-pressure chamber 62, will allow a flow of air to the surroundings via the opening 66.
  • air from the surroundings flows via the opening 66 through the cavity to the low-pressure chamber via the opening 63, when the cavity 67 is facing the opening 63 during rotation of the valve body.
  • the cavity 67 is thus designed to consist of a duct which, preferably in a radial direction, periodically connects with the openings to the high-pressure chamber and the low-pressure chamber.
  • the duct is also designed so that it is connected to the surroundings at least during the said periods or alternatively that it is permanently connected with the surroundings.
  • the duct can with advantage be designed so that it produces a favourable current.
  • the cavity 67 is in one version designed so that the cavity constitutes a volume sector of the valve body with a certain sector angle about the axis of rotation of the valve body. In figure 6a the valve body is shown with a cavity 67 which constitutes a volume sector of 180° angle about the axis of rotation.
  • Fig 6b is in the same way showing a cavity which constitutes a volume sector of 90° angle. It is of course possible to construct the valve body's cavity with other sector angles. It is also possible to furnish the valve space with more than one opening from two low-pressure sources and with more than one opening from two high-pressure sources. whereby the valve body will open to a high-pressure and a low-pressure chamber more than once per revolution.
  • valve space 60 has two openings to the high-pressure source and two openings to the low-pressure source is shown in Fig 6c.
  • the valve body in fig 6c is, in addition, shown with a cavity 67 consisting of a duct 68 running through the valve body. During rotation of the valve body the openings are alternately opened and closed to the surroundings and axially to the valve body.
  • the valve body 65 can also be permitted to slide in the axial direction.
  • the openings 61, 63 to the pressure sources can be given geometries such that the mouth area of the cavity open to the pressure sources change in accordance with the valve body's axial motion. By sliding the valve body in this manner it is possible to regulate the flow and therefore the acoustic pressure. It is convenient to use the said axial displacement within each rotation cycle of the valve body to monitor distortion which arises. This, however, requires quick adjustment of the displacement.
  • Fig 7a and 7b show section views of two different planes, the first of which is perpendicular to the valve body's axis of rotation and the other according to section A - A, in which the positioning of the valve body's 60 opening 66 to the surroundings is depicted.
  • FIG. 8a-8e A further variation of the loudspeaker is shown in Fig. 8a-8e.
  • the loudspeaker according to Fig 8a-8b comprises a space 60 for fluctuating pressure, acoustic pressure, where the said space 60 is in contact with the surrounding air in which it is intended to create acoustic pressure. From both the chamber 62 with higher pressure and the chamber 64 with lower pressure than the surroundings to the space 60 for fluctuating acoustic pressure there are openings 61 and 63 respectively.
  • a valve mechanism in the form of a rocking valve body 65 located in the space 60 for the fluctuating pressure opens alternately the openings 61 and 63 to the high-pressure chamber 62 and the low-pressure chamber 64 respectively, thereby generating the desired acoustic pressure in the space 60.
  • the generated acoustic pressure is carried to the surroundings via the opening 66.
  • the valve body 65 is rocked at the desired frequency, which means that the generated sound frequency can be selected by controlling the oscillation pattern of the valve body
  • valve body 65 can be designed in an alternative way according to figures 8a and 8e.
  • the valve body is best made of an almost semi-spherical or semi-circular cylindrical body or other sector part of a sphere or cylindrical body. In other versions only the envelope surface of one of the said bodies can act as the valve body 65.
  • Fig 8b shows the valve body rocked to its first end position. at which the opening 63 to the low-pressure source is completely open, so that air from the surroundings can flow via the opening 66 towards the low-pressure source.
  • Fig 8c illustrates the valve body's other end position, where the opening 61 to the high-pressure source is completely open, so that air from the high-pressure source flows out to the surroundings. The fluctuating flow of air which is produced here creates the desired sound.
  • both openings to the pressure source can be held partly open when the valve body is in the neutral position, as shown in fig 8d. According to fig 8e the valve body will nevertheless be able to close an opening to a pressure source completely when it is in an end position. This arrangement produces a different acoustic character.
  • valve body 65 can be permitted to move in an axial direction, i.e. along its rocking axis. in the valve space 60.
  • the openings 61, 63 to the pressure sources can have geometries such that the mouth area of the cavity open to the pressure sources changes in accordance with the valve body's axial motion. By moving the valve body in this manner it is possible to regulate the flow and thus the acoustic signal.
  • a further version of the loudspeaker is show in fig 9.
  • the purpose is to generate acoustic pressure at certain frequencies of choice.
  • An ordinary siren according to known techniques consists of a source with compressed air (the pressure of which is higher than the surroundings) and a regulated discharge, which can be carried out, for example. using a mobile cone. This solution is apparent if one considers the left part of fig 9. By moving the cone laterally at a certain frequency the air flow can be regulated and acoustic pressure is created.
  • One drawback is that air is constantly flowing out of the system and thereby impairing efficiency.
  • the version of the sound source according to fig 9 solves this by providing the sound source with a high-pressure source 62 with higher pressure than the surroundings and a low-pressure source 64 with lower pressure than the surroundings.
  • the surroundings here means the pressure outside the opening 66.
  • the opening 61 of the high-pressure source to the valve space 60 is supplied with a first cone 91 that interacts with the, in this version, conically shaped opening 61, whereby the first cone 91 opens or closes the opening 61, when the cone is moved to and fro in the cones axial direction.
  • a second cone 92 opens and closes the flow to the low-pressure source 64, when this second cone is moved to and fro.
  • the flow out from the high-pressure part the flow in to the low-pressure part can be regulated individually by the to and fro movement of the respective cones.
  • the cones 91 and 92 can be controlled individually or together by connecting the cones 91 and 92 with an axis.
  • the sound that is produced by the loudspeaker as a result of the fluctuating pressure at the opening 66 out to the surroundings will have a wider band than that from a conventional siren.
  • the loudspeaker also consists of a control unit 5 (fig.1), which is connected to a drive mechanism for actively setting the valve mechanism in motion, i.e. sliding the tube or rotating the valve body or vibrating the reed according to the valve mechanism in question.
  • a control unit 5 which is connected to a drive mechanism for actively setting the valve mechanism in motion, i.e. sliding the tube or rotating the valve body or vibrating the reed according to the valve mechanism in question.
  • control signals controls the motion of the valve mechanism, and thus the generated acoustic signal.
  • the control unit receives an incoming signal which indicates the desired outgoing signal.
  • the control unit then performs a signal processing task in order to translate the desired signal to corresponding control signals for the desired motion of the valve mechanism.
  • This translation can, for example, be done by a translation table which is established in advance by measurements, by direct functional correlation, or the like.
  • Translation can also be controlled by feedback control, by connecting the gauge 6 for detection of the generated sound to the control unit 5.
  • control unit 5 an essentially linear output characteristic for the loudspeaker can be obtained over a wide frequency band.
  • the control unit preferably contains an artificial neuron net, which one teaches to translate certain input signals to equivalent output signals, and which through self-teaching based on these known cases creates appropriate translations for other cases as well.
  • Fig 2 shows an embodiment where several loudspeaker cells of the type described above are arranged together. In this way the output of the loudspeaker is increased at the same time as the sound wave becomes more planar.
  • the chambers preferably extend over several cells, even if it is possible for each loudspeaker cell to have separate chambers that enclose each tube.
  • the loudspeaker has several loudspeaker cells, and even several pressure chambers stacked on each other, a very strong acoustic pressure can be produced without the need for the pressure in the chambers to be especially great. Consequently, the load on the loudspeaker will be small. which means that lighter components. thinner walls, etc can be used. This allows not only the loudspeaker to be smaller and lighter, but also enhances the sound effect produced.
  • loudspeaker cells When several loudspeaker cells are used in the same loudspeaker they are preferably controlled synchronously. In this way an homogenous sound wave is obtained which is emanated in a direction essentially perpendicular to the plane of the loudspeaker, as shown in Fig 3. It is, however. also possible to let the cells work in a somewhat staggered arrangement. Doing this allows the acoustic wave to be controlled so that it has different directions, as is indicated by the dash-dotted acoustic wave.
  • the directional characteristics of the loudspeaker can accordingly be controlled via an electronic control unit.
  • the invention can be used for a variety of purposes, such as, for example, in traditional hi-fi applications for reproduction of sound. It is however, specially suitable for active noise suppression, since it has a wide frequency spectrum together with high efficiency. high output per weight and area unit, and in particular high output at low frequencies (15-50 Hz). Furthermore, compressed air, which is used to drive the loudspeaker, is often available in such noisy environments where the loudspeaker can be used with advantage.
  • active noise suppression is meant that a signal processing system creates a counter field to a measured field. thereby suppressing the primary sound.
  • the signal processing system can be either adaptive or static.
  • the loudspeaker for instance, can be used for noise suppression in jet engines, such as turbo-fan engines. Such engines produce sound principally in a forward direction, and noise levels can be extremely high (up to 180 dB). This is a serious environmental problem, and efforts are increasingly being made to overcome this.
  • the loudspeaker according to the invention the loudspeaker cells can be placed around the inner wall in the front part of the engine, as shown in Fig 4.
  • the loudspeaker according to the invention may suitably be used for this application since the loudspeaker can be made extremely small and thin, but still produce strong acoustic pressure with an adequate output, which in this case is necessary.
  • Another, similar application is in gas turbine outlets and the like, where as in the previous case very high noise is created, which requires a high output and often at low frequencies.
  • Another similar application of the invention is in active noise suppression of noise from exhaust systems in combustion engines.
  • Fig 5 an alternative embodiment of the invention is shown, which is particularly suitable for active noise suppression in ventilation ducts, although naturally employable in other situations.
  • an outer tube 52 is placed around one tube 51, such as for example a ventilation duct.
  • the inner tube has openings 53 in the side wall,facing the enveloping chambers 54, 55. Some of these chambers preferably have positive pressure while others have negative pressure.
  • the outer tube which is able to slide, is arranged between the chambers 54, 55 and the inner tube. and equipped with openings 56.
  • the openings 53 in the inner tube are alternately exposed for the chamber with positive pressure and the chamber with negative pressure.
  • more or less chambers can be used, more or less openings, and so on.
  • the loudspeaker according to the invention can be manufactured in many different materials, depending on the intended application, such as metal, plastic or composite material.
  • the invention has been described above for an embodiment comprising several chambers with alternate positive and negative pressure. It should be realised, however, that the invention can also be used with a tube which can slide in and out of a positive pressure chamber only. It should also be realised that several chambers with alternate positive and negative pressure can be employed. Additionally, the mobile part has been termed a tube. However, it should be realised that even tube shaped parts with a non-circular cross-section are included here. Furthermore, the tube may well include longitudinal ducts which do not extend along the whole tube, but rather a part of it. All such tube shaped parts with longitudinal ducts are considered to be included in the term tube. Moreover, several different drive mechanisms can be used, as well as other types of modulatable openings. These and similar versions of the invention must be considered to be included in the invention as is defined by the attached claims.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Exhaust Silencers (AREA)

Claims (25)

  1. Druckluftbetriebener Lautsprecher zum Erzeugen eines akustischen Signals,
    wobei der Lautsprecher aufweist:
    wenigstens eine erste Kammer (1; 54; 62), die einen höheren Druck aufweist als die Umgebung, wobei die erste Kammer (1; 54; 62) wenigstens eine erste Öffnung (8; 53; 61) in die Umgebung aufweist,
    wenigstens eine zweite Kammer (2; 55; 64) mit niedrigerem Druck als die Umgebung, wobei diese zweite Kammer (2; 55; 64) wenigstens eine zweite Öffnung (9; 53; 63) in die Umgebung aufweist,
    Ventilmechanismen (3; 52; 65; 91; 92), wobei die erste und zweite Öffnung durch die Ventilmechanismen (3; 52; 65; 91; 92) abwechselnd mit einer ausgewählten Frequenz geöffnet und geschlossen werden,
    dadurch gekennzeichnet, dass der Lautsprecher weiterhin aufweist:
    eine Antriebseinheit zum mechanischen Bewegen des Ventilmechanismus (3; 52; 65; 91; 92) und
    eine Steuerungseinheit, die durch Signalverarbeitung ein Eingabesignal in ein äquivalentes elektrisches Steuerungssignal übersetzt, um ein Ausgabesignal für den Lautsprecher zu erlangen, das dem Eingabesignal entspricht,
    wobei die Steuerungseinheit dafür eingerichtet ist, die Bewegung der Ventilmechanismen (3; 52; 65; 91; 92) und dadurch das erzeugte akustische Signal zu steuern, um eine im Wesentlichen lineare Ausgabe-Kennlinie für den Lautsprecher über ein breites Frequenzband zu erlangen.
  2. Lautsprecher nach Anspruch 1, dadurch gekennzeichnet, dass der Ventilmechanismus (65) aus einem rotierenden Körper besteht.
  3. Lautsprecher nach Anspruch 2, dadurch gekennzeichnet, dass der Ventilmechanismus (65) aus einer Leitung (67, 68) besteht, die während der Drehung des Ventilmechanismus periodisch einen Luftstrom aus der ersten Kammer (62) in die Umgebung entlässt und periodisch einen Luftstrom aus der Umgebung in die zweite Kammer (64) einlässt.
  4. Lautsprecher nach Anspruch 3, dadurch gekennzeichnet, dass der Ventilmechanismus (65) einen Teil eines rotierenden Körpers umfasst, wobei der Querschnitt des Ventilmechanismus quer zu seiner Drehachse wenigstens einen Sektor eines Kreises mit Sektorwinkeln umfasst, die vorzugsweise größer sind als der Durchmesser der größten der ersten und zweiten Öffnung (61,63).
  5. Lautsprecher nach Anspruch 2, dadurch gekennzeichnet, dass der Ventilmechanismus (65) aus einem rotierenden Körper in Form einer Ummantelung am Umfang des Körpers oder aus mehreren Ummantelungsteilen besteht, die am Umfang des rotierenden Körpers verteilt sind.
  6. Lautsprecher nach Anspruch 3, dadurch gekennzeichnet, dass der Ventilmechanismus (65) aus einer Leitung (68) besteht, die gerade durch den Ventilmechanismus verläuft.
  7. Lautsprecher nach Anspruch 1, dadurch gekennzeichnet, dass der Ventilmechanismus (65) einen sich hin- und herbewegenden Körper umfasst, der sich um eine Drehachse in einem Raum (60), der die Öffnungen (61, 63) in die erste (62) und die zweite Kammer (64) und in die Umgebung aufweist, hin- und herbewegt.
  8. Lautsprecher nach Anspruch 7, dadurch gekennzeichnet, dass der sich hin- und herbewegende Körper in einer Endposition die Öffnung (61) in die erste Kammer (62) und in der anderen Endposition die Öffnung (63) in die zweite Kammer (64) ganz oder teilweise schließt.
  9. Lautsprecher nach Anspruch 8, dadurch gekennzeichnet, dass der sich hin- und herbewegende Körper aus einem Kugelsegment einer Kugel oder aus einem Segment eines kreisförmigen Zylinders besteht.
  10. Lautsprecher nach einem der Ansprüche 2 bis 9, dadurch gekennzeichnet, dass der Ventilmechanismus (65) in Richtung seiner Drehachse verschoben werden kann, wodurch sich die Flächen der ersten und der zweiten Öffnung (61, 63) ändern, was die Art des Schalls, der von dem Lautsprecher erzeugt wird, ändert.
  11. Lautsprecher nach Anspruch 1, dadurch gekennzeichnet, dass der Ventilmechanismus (3) aus einer Röhre mit einer Öffnung in die Umgebung besteht, die durch einen Antriebsmechanismus durch die Wände der Kammern (1, 2) verschoben werden kann, und dass die Röhre an ihrer Hüllfläche Öffnungen (4) aufweist, die so angeordnet sind, dass die Röhrenöffnungen (4) zwischen den Kammern (1, 2) bewegt werden, wenn die Röhre (3) bewegt wird.
  12. Lautsprecher nach Anspruch 11, dadurch gekennzeichnet, dass wenigstens vier Kammern (1, 2) mit abwechselndem Überdruck und Unterdruck übereinander in einem sandwichartigen Aufbau gestapelt sind.
  13. Lautsprecher nach Anspruch 11, dadurch gekennzeichnet, dass die Röhre (3) eine Anzahl von Sätzen von Öffnungen an der Hüllfläche (4) aufweist, so dass diese Anzahl der Anzahl der Kammern (1, 2) mit Über- und Unterdruck entspricht.
  14. Lautsprecher nach Anspruch 11, dadurch gekennzeichnet, dass er mehrere Röhren (3) aufweist, die über eine Oberfläche verteilt sind.
  15. Lautsprecher nach Anspruch 11, dadurch gekennzeichnet, dass der Antriebsmechanismus zum Verschieben der Röhre (3) eine elektromagnetische Antriebseinheit ist, die eine Spule aufweist.
  16. Lautsprecher nach Anspruch 11, dadurch gekennzeichnet, dass der Antriebsmechanismus zum Verschieben der Röhre (3) eine piezoelektrische Antriebseinheit ist.
  17. Lautsprecher nach einem der vorigen Ansprüche, dadurch gekennzeichnet, dass die Steuerungseinheit (5) ein künstliches Neuronennetz umfasst.
  18. Lautsprecher nach einem der vorigen Ansprüche, dadurch gekennzeichnet, dass die Steuerungseinheit (5) mit einem Messgerät (6) zum Erfassen des Ausgabesignals des Lautsprechers für eine Rückkopplungssteuerung verbunden ist.
  19. Verwendung eines Lautsprechers nach Anspruch 1 für eine aktive Geräuschunterdrückung.
  20. Verwendung nach Anspruch 19 bei einer aktiven Geräuschunterdrückung bei Düsenmotoren und insbesondere Turbofan-Motoren.
  21. Verwendung nach Anspruch 19 bei einer aktiven Geräuschunterdrückung bei Lüftungssystemen.
  22. Verwendung nach Anspruch 19 bei einer aktiven Geräuschunterdrückung bei Gasturbinenausgängen.
  23. Verwendung nach Anspruch 19 bei einer aktiven Geräuschunterdrückung bei Auslasssystemen von Verbrennungsmotoren.
  24. Verwendung nach Anspruch 19 bei einer Schallwiedergabe bei Hi-Fi-Anwendungen wie in Konzerten, Kinos und Wohnungen.
  25. Verwendung nach Anspruch 19 bei einer Schallwiedergabe in Kopfhörern, Telefonen, Ohrhörern und dergleichen.
EP99925504A 1998-04-09 1999-04-09 Druckluftgetriebener lautsprecher und dessen verwendung Expired - Lifetime EP1084589B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9801257A SE9801257D0 (sv) 1998-04-09 1998-04-09 Pneumatiskt driven högtalare
SE9801257 1998-04-09
PCT/SE1999/000586 WO1999053720A1 (en) 1998-04-09 1999-04-09 Pneumatically driven loudspeaker and its use

Publications (2)

Publication Number Publication Date
EP1084589A1 EP1084589A1 (de) 2001-03-21
EP1084589B1 true EP1084589B1 (de) 2004-09-22

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EP99925504A Expired - Lifetime EP1084589B1 (de) 1998-04-09 1999-04-09 Druckluftgetriebener lautsprecher und dessen verwendung

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EP (1) EP1084589B1 (de)
AU (1) AU4176799A (de)
DE (1) DE69920445D1 (de)
SE (1) SE9801257D0 (de)
WO (1) WO1999053720A1 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE514782C2 (sv) * 1999-12-08 2001-04-23 Saab Ab Pneumatiskt driven högtalare
FR2808916B1 (fr) * 2000-05-11 2003-08-15 Jean Laurent Peube Source et systeme electroaeroacoustiques pour controle actif du bruit
WO2015041623A1 (en) * 2013-09-20 2015-03-26 Dushko Yuriy Viktorovich The method of sound oscillations generation and the device for its implementation
CN104219608B (zh) * 2014-09-15 2018-08-10 精拓丽音科技（北京）有限公司 一种调制型压电扬声器、扬声器系统及其控制方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE4662T1 (de) * 1978-07-03 1983-09-15 Mats Olsson Konsult Ab Niederfrequenz schallgeber.
FR2729781B1 (fr) * 1995-01-23 1997-04-18 Bertin & Cie Dispositif de controle actif du bruit
DE19508200A1 (de) * 1995-03-10 1996-09-12 Norbert Schaefer Lautsprecher, insbesondere Tieftöner

Also Published As

Publication number Publication date
EP1084589A1 (de) 2001-03-21
AU4176799A (en) 1999-11-01
SE9801257D0 (sv) 1998-04-09
DE69920445D1 (de) 2004-10-28
WO1999053720A1 (en) 1999-10-21

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