EP0011817A1 - Directional microphone according to the interference principle - Google Patents

Directional microphone according to the interference principle Download PDF

Info

Publication number
EP0011817A1
EP0011817A1 EP79104634A EP79104634A EP0011817A1 EP 0011817 A1 EP0011817 A1 EP 0011817A1 EP 79104634 A EP79104634 A EP 79104634A EP 79104634 A EP79104634 A EP 79104634A EP 0011817 A1 EP0011817 A1 EP 0011817A1
Authority
EP
European Patent Office
Prior art keywords
reflector
tube
directional microphone
microphone according
interference
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
EP79104634A
Other languages
German (de)
French (fr)
Other versions
EP0011817B1 (en
Inventor
Alfred Zlevor
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.)
AKG Acoustics GmbH
Original Assignee
AKG Akustische und Kino Geraete GmbH
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 AKG Akustische und Kino Geraete GmbH filed Critical AKG Akustische und Kino Geraete GmbH
Publication of EP0011817A1 publication Critical patent/EP0011817A1/en
Application granted granted Critical
Publication of EP0011817B1 publication Critical patent/EP0011817B1/en
Expired legal-status Critical Current

Links

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
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
    • H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
    • H04R1/342—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means for microphones

Definitions

  • the invention relates to a directional microphone based on the interference principle, with a single, one or more longitudinal slots or lateral openings (bores) having elongated tube, at one end of which at least one electroacoustic transducer is arranged.
  • the disadvantage of this known construction lies primarily in the fact that the transmission factor at the high frequencies is significantly worse than at all other frequencies.
  • the drop in the high frequencies is due in particular to the absorption of the same on the inner wall of the pipe, mainly in those places where there is acoustic frictional resistance.
  • the load on the transducer membrane from the air column in the tube also increases the transmission factor in the medium frequency range, which increases the impression of poor transmission of the high frequencies.
  • the microphones with a similarly sharply focused directional characteristic include the directional microphones with a reflector, usually corresponding to a parabolic mirror, in the focal point of which a microphone is arranged.
  • a reflector usually corresponding to a parabolic mirror, in the focal point of which a microphone is arranged.
  • a reflector with large and therefore bulky dimensions is required, because in principle the reflector diameter should be at least equal to the wavelength of the lower limit frequency to be transmitted. Since such microphones are mostly used outdoors, they must be built to be extremely stable in order to withstand the transport and influences of the great outdoors. A lack of stability significantly deteriorates the directivity and sensitivity.
  • the invention has set itself the goal of creating a handy directional microphone that is easy to use and combines the advantages of the interference microphone with those of a reflector microphone.
  • This aim is achieved with a directional microphone of the type described in the introduction in that in the area of the free tube end there is an acoustic reflector arrangement, which preferably contains sound waves in the upper hearing frequency range for opening the interference tube bundles, is provided. Since the reflector arrangement is preferably only intended to collect high frequencies, the reflector arrangement can be made relatively small. It hardly increases the space requirement and the weight of the interference microphone equipped with it. Due to the small dimensions, the stability of the entire arrangement is very good.
  • the reflector arrangement can consist of a reflector which has an approximately bowl-shaped shape, the bottom of which has an opening which corresponds to the diameter of the interference tube and is connected there to the tube in the region of the free tube end.
  • the reflector at the opening corresponding to the tube diameter is provided with a sleeve which surrounds the interference tube and is arranged either fixedly or displaceably on the tube.
  • means for fixing the sleeve to the tube must be provided, for example in the form of one or more clamping screws. Instead of such screws, the operation of which can be cumbersome and time-consuming, it is also possible to provide a bayonet arrangement, as is often used in photographic devices with interchangeable lenses.
  • the reflector which is arranged in the region of the free tube end, usually has at least approximately the shape of a parabolic mirror, the mouth opening of the interference tube lying approximately in a plane in which the focal point of the reflector is also located. It is not absolutely necessary that the parabolic shape of the reflector is fully developed. Since the central parts do little or nothing to bundle the sound waves anyway, the reflector can only be used as a ring be shaped section of a parabolic, which has the consequence that the opening of the reflector, which corresponded to the outer diameter of the interference tube in the embodiment described above, is now substantially larger and allows unimpeded access of the sound waves to the longitudinal slots of the interference tube. In this case, however, support elements are required which connect the reflector to the interference tube in the region of the tube end. Band-shaped parts are suitable as support elements, the narrow sides of which lie in planes through the pipe axis.
  • the spatial directional characteristic is not club-shaped, but instead has an elliptical instead of a circular shape, for example in a section perpendicular to the axis of the main direction of reception, this can be achieved in the invention in that the reflector is given a corresponding configuration so that it is divided into two Main axes placed planes have different, but preferably symmetrical curvatures.
  • the reflector arrangement consists of two reflective parts, u. between a reflector according to one of the exemplary embodiments described above, the reflecting surface of which is to be aligned with the sound source, and a second, smaller reflector, the reflecting surface of which faces the mouth of the interference tube.
  • An analog arrangement known as "Schmidt-Optik” has become known in lighting technology. It is currently used in facilities for large-screen projection of television images in general. There is a corresponding arrangement in the acoustics, especially in the Zu connection with directional microphones based on the interference principle, have not yet been used.
  • the second, smaller reflector which, like the larger reflector facing the sound source, has a common axis with the interference tube, reflects the sound waves collected by the large reflector into the mouth of the tube, which significantly improves the efficiency compared to the exemplary embodiments with only one reflector.
  • the reflector arrangement is either connected to the interference tube to form a mechanical unit or is an independent unit which can be placed or removed from the interference tube as required.
  • a bowl-shaped reflector 4 is arranged at the opening of the interference tube 2, which is opposite the opening provided with the transducer 1.
  • the side openings 3 in the interference tube are covered with a suitable acoustic friction material in order to achieve the necessary phase rotation for the formation of the highly bundled directional characteristic and / or a side slot is made, the width of which changes in a wedge shape along the tube.
  • FIG. 2 The opening of the reflector 4, into which the interference tube 2 is inserted in the exemplary embodiment according to FIG. 1, is provided with a sleeve 5 which can be pushed onto the interference tube quickly. With a screw 6, which passes through the wall of the sleeve 5, the reflector 4 can be held on the tube 2 in a freely selectable position.
  • Fig. 3 shows a reflector 4, the outer boundary is not circular, but is deformed elliptically. This results in two mutually perpendicular main axes d 1 and d 2 , in their planes, which also Include the axis of the interference tube 2, the reflector 4 has different curvatures that are symmetrical in this embodiment.
  • the reflector 7 represents a section of a parabolic element, so that the opening, which corresponded to the diameter of the tube 2 in the previously described exemplary embodiments, is substantially larger here.
  • the reflector 7 is carried by, for example, three support elements 8 which extend from the cuff 5.
  • the supports 8 consist of narrow, band-shaped elements, the narrow sides of which lie in planes through the tube axis.
  • FIG. 5 is a front view of the exemplary embodiment shown in section in FIG.
  • a reflector arrangement with a particularly good effect is shown schematically in section in FIG.
  • the annular reflector 7 ' as is also used in the exemplary embodiment according to FIG. 4, it has a second, smaller reflector 9, which receives the sound waves of the higher frequency range collected by the reflector 7' and deflects them so that they directly can enter the mouth of the interference tube 2.
  • the sound waves are guided approximately according to the dashed lines labeled 10. It can be seen that the proportion of sound waves collected by the reflector 7 'which can enter the opening of the interference tube 2 is undoubtedly greater in this exemplary embodiment than in those exemplary embodiments which only have one have only one reflector.
  • the reflector arrangement can either be firmly connected to the interference tube or can be designed to be detachable.

Landscapes

  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)

Abstract

Bei einem Richtmikrophon nach dem Interferenzprinzip mit einem einzigen, einen oder mehrere Längsschlitze oder seitliche Öffnungen (Bohrungen) aufweisenden, langgestreckten Rohr, ist an dessen einem Ende wenigstens ein elektroakustischer Wandler angeordnet. Um ein handliches Richtmikrophon zu schaffen, das leicht zu handhaben ist und die Vorteile des Interferenzmikrophons mit denen eines Reflektormikrophons vereint, ist im Bereich des freien Rohrendes eine akustische Reflektoranordnung vorgesehen, die vorzugsweise Schallwellen des oberen Hörfrequenzbereiches zur Einspracheöffnung des Interferenzrohres bündelt.In the case of a directional microphone based on the interference principle with a single, elongated tube having one or more longitudinal slots or lateral openings (bores), at least one electroacoustic transducer is arranged at one end. In order to create a handy directional microphone that is easy to handle and combines the advantages of the interference microphone with those of a reflector microphone, an acoustic reflector arrangement is provided in the area of the free tube end, which preferably bundles sound waves in the upper hearing frequency range for opening the interference tube.

Description

Die Erfindung betrifft ein Richtmikrophon nach dem Interferenzprinzip, mit einem einzigen, einen oder mehrere Längsschlitze oder seitliche Öffnungen (Bohrungen) aufweisenden, langgestreckten Rohr, an dessen einem Ende wenigstens ein elektroakustischer Wandler angeordnet ist.The invention relates to a directional microphone based on the interference principle, with a single, one or more longitudinal slots or lateral openings (bores) having elongated tube, at one end of which at least one electroacoustic transducer is arranged.

Der Nachteil dieser bekannten Konstruktion liegt vor allem darin, daß das übertragungsmaß bei den hohen Frequenzen deutlich schlechter ist als bei allen anderen Frequenzen. Der Abfall bei den hohen Frequenzen ist insbesondere auf die Absorption derselben an der Rohrinnenwand, hauptsächlich an jenen Stellen, an denen akustische Reibungswiderstände vorhanden sind, zurückzuführen. Die Belastung der Wandlermembran durch die Luftsäule im Rohr erhöht außerdem das Obertragungsmaß im mittleren Frequenzbereich, wodurch der Eindruck einer schlechten Obertragung der hohen Frequenzen verstärkt wird.The disadvantage of this known construction lies primarily in the fact that the transmission factor at the high frequencies is significantly worse than at all other frequencies. The drop in the high frequencies is due in particular to the absorption of the same on the inner wall of the pipe, mainly in those places where there is acoustic frictional resistance. The load on the transducer membrane from the air column in the tube also increases the transmission factor in the medium frequency range, which increases the impression of poor transmission of the high frequencies.

Um diesen Mangel zu beheben wurde versucht, an Stelle eines einzigen Rohres ein Rohrbündel zu setzen, dessen Rohre unterschiedliche Längen aufweisen. Durch sorgfältige akustische Abstimmung der einzelnen Rohre des RohrbUndels erreicht man zwar eine Verbesserung, die Handhabung eines solchen Rohrbündels ist aber naturgemäß ungünstiger als die eines einzelnen Rohres, abgesehen davon, daß die Abstimmung der einzelnen Rohre des Bündels auch ziemlich schwierig ist.In order to remedy this deficiency, an attempt was made to place a tube bundle instead of a single tube, the tubes of which have different lengths. Through careful acoustic coordination of the individual pipes of the Although tube bundles are improved, the handling of such a tube bundle is naturally less favorable than that of an individual tube, apart from the fact that the coordination of the individual tubes of the bundle is also quite difficult.

Zu den Mikrophonen mit ähnlicher scharf gebündelter Richtcharakteristik, wie ein Interferenzmikrophon, gehören die Richtmikrophone mit einem meist einem Parabolspiegel entsprechendem Reflektor, in dessen Brennpunkt ein Mikrophon angeordnet ist. Bei derartigen Mikrophonen sind allerdings einige wesentliche, nur schwer erfüllbare Forderungen zu berücksichtigen, die die praktische Ausführung erschweren.The microphones with a similarly sharply focused directional characteristic, such as an interference microphone, include the directional microphones with a reflector, usually corresponding to a parabolic mirror, in the focal point of which a microphone is arranged. With such microphones, however, some essential requirements that are difficult to meet have to be taken into account and make practical implementation difficult.

Für eine wirksame Bündelung tiefer Frequenzen bedarf es eines Reflektors mit großen und daher unhandlichen Abmessungen, denn im Prinzip sollte der Reflektordurchmesser zumindest gleich der Wellenlänge der zu übertragenden unteren Grenzfrequenz sein. Da derartige Mikrophone meist im Freien verwendet werden, müssen sie außerordentlich stabil gebaut sein, um dem Transport und den Einflüssen der freien Natur widerstehen zu können. Mangelnde Stabilität verschlechtert wesentlich die Richtwirkung und die Empfindlichkeit.For effective bundling of low frequencies, a reflector with large and therefore bulky dimensions is required, because in principle the reflector diameter should be at least equal to the wavelength of the lower limit frequency to be transmitted. Since such microphones are mostly used outdoors, they must be built to be extremely stable in order to withstand the transport and influences of the great outdoors. A lack of stability significantly deteriorates the directivity and sensitivity.

Die Erfindung hat es sich zum Ziel gesetzt, ein handliches Richtmikrophon zu schaffen, das leicht zu handhaben ist und die Vorteile des Interferenzmikrophons mit denen eines Reflektormikrophons vereint. Dieses Ziel wird bei einem Richtmikrophon der eingangs beschriebenen Art dadurch erreicht, daß im Bereich des freien Rohrendes eine akustische Reflektoranordnung, die vorzugsweise Schallwellen des oberen Hörfrequenzbereiches zur Einspracheöffnung des Interferenzfohres bündelt, vorgesehen ist. Da die Reflektoranordnung vorzugsweise nur zur Sammlung hoher Frequenzen bestimmt ist, kann die Reflektoranordnung verhältnismässig klein ausgeführt werden. Sie vergrößert kaum den Raumbedarf und das Gewicht des mit ihr ausgerüsteten Interferenzmikrophons. Infolge der geringen Abmessungen ist die Stabilität der gesamten Anordnung sehr gut. Im einfachsten Falle kann die Reflektoranordnung aus einem Reflektor bestehen, der eine etwa schüsselförmige Gestalt hat, deren Boden eine öffnung aufweist, die dem Durchmesser des Interferenzrohres entspricht und dort im Bereich des freien Rohrendes mit dem Rohr verbunden ist. Bei einem bevorzugten Ausführungsbeispiel ist der Reflektor bei der dem Rohrdurchmesser entsprechenden öffnung mit einer das Interferenzrohr umschließenden Manschette versehen, die entweder fest oder am Rohr verschieblich angeordnet ist. Im letzteren Falle müssen selbstverständlich Mittel zur Fixierung der Manschette am Rohr vorgesehen sein, beispielsweise in Form von einer oder mehreren Klemmschrauben. An Stelle solcher Schrauben, deren Bedienung umständlich und zeitraubend sein kann, ist es auch möglich, eine Bajonettanordnung vorzusehen, wie sie häufig bei photographischen Geräten mit Wechselobjektiven verwendet wird.The invention has set itself the goal of creating a handy directional microphone that is easy to use and combines the advantages of the interference microphone with those of a reflector microphone. This aim is achieved with a directional microphone of the type described in the introduction in that in the area of the free tube end there is an acoustic reflector arrangement, which preferably contains sound waves in the upper hearing frequency range for opening the interference tube bundles, is provided. Since the reflector arrangement is preferably only intended to collect high frequencies, the reflector arrangement can be made relatively small. It hardly increases the space requirement and the weight of the interference microphone equipped with it. Due to the small dimensions, the stability of the entire arrangement is very good. In the simplest case, the reflector arrangement can consist of a reflector which has an approximately bowl-shaped shape, the bottom of which has an opening which corresponds to the diameter of the interference tube and is connected there to the tube in the region of the free tube end. In a preferred exemplary embodiment, the reflector at the opening corresponding to the tube diameter is provided with a sleeve which surrounds the interference tube and is arranged either fixedly or displaceably on the tube. In the latter case, of course, means for fixing the sleeve to the tube must be provided, for example in the form of one or more clamping screws. Instead of such screws, the operation of which can be cumbersome and time-consuming, it is also possible to provide a bayonet arrangement, as is often used in photographic devices with interchangeable lenses.

Oblicherweise hat der Reflektor, der im Bereich des freien Rohrendes angeordnet ist, wenigstens angenähert die Form eines Parabolspiegels, wobei die Einspracheöffnung des Interferenzrohres etwa in einer Ebene liegt, in der sich auch der Brennpunkt des Reflektors befindet. Es ist nicht unbedingt erforderlich, daß die Parabolform des Reflektors voll ausgebildet ist. Da die zentralen Teile ohnehin wenig oder nichts zur Bündelung der Schallwellen beitragen,kann der Reflektor auch nur als ringförmiger Abschnitt eines Parabols ausgebildet sein, was zur Folge hat, daß die öffnung des Reflektors, die beim vorstehend beschriebenen Ausführungsbeispiel dem äußeren Durchmesser des Interferenzrohres entsprach, nunmehr wesentlich größer ist und einen ungehinderten Zutritt der Schallwellen zu den Längsschlitzen des Interferenzrohres gestattet. In diesem Falle sind allerdings Stützelemente erforderlich, die den Reflektor im Bereich des Rohrendes mit dem Interferenzrohr.verbinden. Als Stützelemente eignen sich bandförmige Teile, deren Schmalseiten in Ebenen durch die Rohrachse liegen.The reflector, which is arranged in the region of the free tube end, usually has at least approximately the shape of a parabolic mirror, the mouth opening of the interference tube lying approximately in a plane in which the focal point of the reflector is also located. It is not absolutely necessary that the parabolic shape of the reflector is fully developed. Since the central parts do little or nothing to bundle the sound waves anyway, the reflector can only be used as a ring be shaped section of a parabolic, which has the consequence that the opening of the reflector, which corresponded to the outer diameter of the interference tube in the embodiment described above, is now substantially larger and allows unimpeded access of the sound waves to the longitudinal slots of the interference tube. In this case, however, support elements are required which connect the reflector to the interference tube in the region of the tube end. Band-shaped parts are suitable as support elements, the narrow sides of which lie in planes through the pipe axis.

Soll die räumliche Richtcharakteristik nicht keulenförmig sein, sondern beispielsweise bei einem Schnitt senkrecht zur Achse der Hauptempfangsrichtung eine elliptische statt der Kreisform aufweisen, so kann dies bei der Erfindung dadurch erzielt werden, daß dem Reflektor eine entsprechende Ausgestaltung erteilt wird, so daß er in zwei durch Hauptachsen gelegte Ebenen unterschiedliche, vorzugsweise jedoch symmetrische Krümmungen aufweist.If the spatial directional characteristic is not club-shaped, but instead has an elliptical instead of a circular shape, for example in a section perpendicular to the axis of the main direction of reception, this can be achieved in the invention in that the reflector is given a corresponding configuration so that it is divided into two Main axes placed planes have different, but preferably symmetrical curvatures.

In einer Weiterbildung der Erfindung besteht die Reflektoranordnung aus zwei reflektierenden Teilen, u. zw. einem Reflektor gemäss einem der vorstehend beschriebenen Ausfuhrungsbeispiele, dessen reflektierende Fläche zur Schallquelle auszurichten ist, und einem zweiten, kleineren Reflektor, dessen reflektierende Oberfläche der Einspracheöffnung des Interferenzrohres zugewendet ist. In der Lichttechnik ist eine analoge Anordnung unter der Bezeichnung "Schmidt-Optik" bekannt geworden. Sie wird dzt, bei Einrichtungen für die Großbildprojektion von Fernsehbildern allgemein verwendet. In der Akustik ist eine entsprechende Anordnung, insbesondere im Zusammenhang mit Richtmikrophonen nach dem Interferenzprinzip, noch nicht verwendet worden. Der zweite, kleinere Reflektor, der ebenso wie der der Schallquelle zugekehrte größere Reflektor eine gemeinsame Achse mit dem Interferenzrohr besitzt, reflektiert die vom großen Reflektor gesammelten Schallwellen in die Einspracheöffnung des Rohres, wodurch der Wirkungsgrad gegenüber den Ausführungsbeispielen mit nur einem Reflektor wesentlich verbessert wird.In a development of the invention, the reflector arrangement consists of two reflective parts, u. between a reflector according to one of the exemplary embodiments described above, the reflecting surface of which is to be aligned with the sound source, and a second, smaller reflector, the reflecting surface of which faces the mouth of the interference tube. An analog arrangement known as "Schmidt-Optik" has become known in lighting technology. It is currently used in facilities for large-screen projection of television images in general. There is a corresponding arrangement in the acoustics, especially in the Zu connection with directional microphones based on the interference principle, have not yet been used. The second, smaller reflector, which, like the larger reflector facing the sound source, has a common axis with the interference tube, reflects the sound waves collected by the large reflector into the mouth of the tube, which significantly improves the efficiency compared to the exemplary embodiments with only one reflector.

Allen Ausführungsbeispielen ist gemeinsam, daß die Reflektoranordnung entweder mit dem Interferenzrohr zu einer mechanischen Einheit verbunden ist oder ein selbständiges Aggregat darstellt, das je nach Bedarf auf das Interferenzrohr aufgesetzt oder abgenommen werden kann.All of the exemplary embodiments have in common that the reflector arrangement is either connected to the interference tube to form a mechanical unit or is an independent unit which can be placed or removed from the interference tube as required.

Weitere Einzelheiten der Erfindung können der folgenden Beschreibung anhand der Zeichnung entnommen werden.Further details of the invention can be found in the following description with reference to the drawing.

Es zeigen

  • Fig. 1 schematisch einen Querschnitt durch ein einfaches Ausführungsbeispiel,
  • Fig. 2 ebenfalls im Querschnitt einen Reflektor mit einer Manschette,
  • Fig. 3 einen von der Parabolform abweichenden Reflektor,
  • Fig. 4 im schematischen Querschnitt die Verwendung eines ringförmigen Reflektors,
  • Fig. 5 eine Vorderansicht der Anordnung nach Fig. 4, und
  • Fig. 6 ein Ausführungsbeispiel mit einer aus zwei Reflektoren bestehenden Anordnung im schematischen Querschnitt.
Show it
  • 1 schematically shows a cross section through a simple embodiment,
  • 2 also in cross section a reflector with a sleeve,
  • 3 a reflector deviating from the parabolic shape,
  • 4 shows a schematic cross section of the use of an annular reflector,
  • Fig. 5 is a front view of the arrangement of FIG. 4, and
  • Fig. 6 shows an embodiment with an arrangement consisting of two reflectors in a schematic cross section.

Um den übertragungsfaktor eines Interferenzmikrophones mit nur einem Rohr im höherfrequenten Bereich zu verbessern, ist beim einfachsten Ausführungsbeispiel gemäß Fig. 1 an der Öffnung des Interferenzrohres 2, die der mit dem Wandler 1 versehenen Uffnung gegenüberliegt, ein schüsselförmiger Reflektor 4 angeordnet.In order to improve the transmission factor of an interference microphone with only one tube in the higher frequency range, in the simplest embodiment according to FIG. 1 a bowl-shaped reflector 4 is arranged at the opening of the interference tube 2, which is opposite the opening provided with the transducer 1.

Die seitlichen öffnungen 3 im Interferenzrohr sind zwecks Erzielung der erforderlichen Phasendrehung für die Ausbildung der stark gebündelten Richtcharakteristik mit einem geeigneten akustischen Reibungsmaterial abgedeckt und/oder es wird ein seitlicher Schlitz angebracht, dessen Breite sich keilförmig entlang des Rohres ändert.The side openings 3 in the interference tube are covered with a suitable acoustic friction material in order to achieve the necessary phase rotation for the formation of the highly bundled directional characteristic and / or a side slot is made, the width of which changes in a wedge shape along the tube.

In manchen Fällen ist es erwünscht, z.B. beim Transport, daß man den Reflektor vom Interferenzrohr abnehmen kann. Die Lösung dieser Aufgabe ist relativ einfach und in Fig. 2 dargestellt. Die öffnung des Reflektors 4, in die beim Ausführungsbeispiel nach Fig.l das Interferenzrohr 2 eingesetzt ist, ist.mit einer Manschette 5 versehen, die auf das Interferenzrohr zügig aufschiebbar ist. Mit einer Schraube 6, die die Wand der Manschette 5 durchsetzt, kann der Reflektor 4 am Rohr 2 in einer gegebenenfalls frei wählbaren Stellung festgehalten werden.In some cases it is desirable e.g. during transport that the reflector can be removed from the interference tube. The solution to this problem is relatively simple and is shown in FIG. 2. The opening of the reflector 4, into which the interference tube 2 is inserted in the exemplary embodiment according to FIG. 1, is provided with a sleeve 5 which can be pushed onto the interference tube quickly. With a screw 6, which passes through the wall of the sleeve 5, the reflector 4 can be held on the tube 2 in a freely selectable position.

Fig. 3 zeigt einen Reflektor 4, dessen äußere Begrenzung nicht kreisförmig, sondern elliptisch verformt ist. Es ergeben sich dabei zwei senkrecht aufeinanderstehende Hauptachsen dl und d2, in deren Ebenen, die auch die Achse des Interferenzrohres 2 einschließen, der Reflektor 4 unterschiedliche Krümmungen aufweist, die bei diesem Ausführungsbeispiel symmetrisch sind.Fig. 3 shows a reflector 4, the outer boundary is not circular, but is deformed elliptically. This results in two mutually perpendicular main axes d 1 and d 2 , in their planes, which also Include the axis of the interference tube 2, the reflector 4 has different curvatures that are symmetrical in this embodiment.

Bei dem in Fig. 4 gezeigten Ausführungsbeispiel stellt der Reflektor 7 einen Abschnitt eines Parabols dar, so daß die öffnung, die bei den bisher beschriebenen Ausführungsbeispielen dem Durchmesser des Rohres 2 entsprach, hier wesentlich größer ist. Der Reflektor 7 wird von beispielsweise drei Stützelementen 8 getragen, die von der Manschette 5 ausgehen. Um den Schallzutritt zu den Schlitzen 3 im Interferenzrohr 2 nicht zu behindern, bestehen die Stützen 8 aus schmalen, bandförmigen Elementen, deren Schmalseiten in Ebenen durch die Rohrachse liegen.In the exemplary embodiment shown in FIG. 4, the reflector 7 represents a section of a parabolic element, so that the opening, which corresponded to the diameter of the tube 2 in the previously described exemplary embodiments, is substantially larger here. The reflector 7 is carried by, for example, three support elements 8 which extend from the cuff 5. In order not to obstruct the sound access to the slots 3 in the interference tube 2, the supports 8 consist of narrow, band-shaped elements, the narrow sides of which lie in planes through the tube axis.

Dies ist besonders deutlich Fig.5 zu entnehmen, die eine Vorderansicht des in Fig.4 im Schnitt dargestellten Ausführungsbeispiels ist.This can be seen particularly clearly in FIG. 5, which is a front view of the exemplary embodiment shown in section in FIG.

Eine Reflektoranordnung mit besonders guter Wirkung ist in Fig.6 schematisch im Schnitt dargestellt. Sie weist außer dem ringförmigen Reflektor 7', wie er auch bei dem Ausführungsbeispiel gemäß Fig. 4 verwendet wird, einen zweiten,kleineren Reflektor 9-auf, der die vom Reflektor 7' gesammelten Schallwellen des höheren Frequenzbereiches aufnimmt und so umlenkt, dass sie direkt in die Einspracheöffnung des Interferenzrohres 2 eintreten können. Die Schallwellen werden etwa nach den mit 10 bezeichneten strichlierten Linien geführt. Es ist ersichtlich, daß der Anteil der vom Reflektor 7' gesammelten Schallwellen, der in die öffnung des Interferenzrohres 2 eintreten kann, bei diesem Ausführungsbeispiel zweifellos größer ist, als bei jenen Ausführungsbeispielen, die nur einen einzigen Reflektor besitzen. Man kann auch bei diesem Ausführungsbeispiel wie bei den früheren die Reflektoranordnung entweder fest mit dem Interferenzrohr verbinden oder aber auch lösbar ausbilden.A reflector arrangement with a particularly good effect is shown schematically in section in FIG. In addition to the annular reflector 7 ', as is also used in the exemplary embodiment according to FIG. 4, it has a second, smaller reflector 9, which receives the sound waves of the higher frequency range collected by the reflector 7' and deflects them so that they directly can enter the mouth of the interference tube 2. The sound waves are guided approximately according to the dashed lines labeled 10. It can be seen that the proportion of sound waves collected by the reflector 7 'which can enter the opening of the interference tube 2 is undoubtedly greater in this exemplary embodiment than in those exemplary embodiments which only have one have only one reflector. In this exemplary embodiment, too, as in the previous ones, the reflector arrangement can either be firmly connected to the interference tube or can be designed to be detachable.

Claims (12)

1. Richtmikrophon nach dem Interferenzprinzip, mit einem einzigen, einen oder mehrere Längsschlitze oder seitliche Öffnungen (Bohrungen) aufweisenden,langgestreckten Rohr, an dessen einem Ende wenigstens ein elektroakustischer Wandler angeordnet ist, dadurch gekennzeichnet, daß im Bereich des freien Rohrendes eine akustische Reflektoranordnung (4; 7; 7' und 9), die vorzugsweise Schallwellen des oberen Hörfrequenzbereiches zur Einspracheöffnung des Interferenzrohres (2) bündelt, vorgesehen ist.1. directional microphone on the interference principle, with a single, one or more longitudinal slots or side openings (bores) having elongated tube, at one end of which at least one electroacoustic transducer is arranged, characterized in that in the area of the free tube end an acoustic reflector arrangement ( 4; 7; 7 'and 9), which preferably bundles sound waves of the upper hearing frequency range for opening the interference tube (2). 2. Richtmikrophon nach Anspruch 1, dadurch gekennzeichnet, daß ein schüsselförmiger Reflektor (4) vorgesehen ist, der in seinem Boden eine zentrale Öffnung aufweist, die dem Durchmesser des Interferenzrohres (2) entspricht und dort im Bereich des freien Rohrendes mit dem Rohr (2) verbunden ist.2. Directional microphone according to claim 1, characterized in that a bowl-shaped reflector (4) is provided which has a central opening in its bottom which corresponds to the diameter of the interference tube (2) and there in the region of the free tube end with the tube (2nd ) connected is. 3. Richtmikrophon nach Anspruch 2, dadurch gekennzeichnet, daß der Reflektor (4) bei der dem Rohrdurchmesser entsprechenden Öffnung mit einer Manschette (5) versehen ist, über die er mit dem Interferenzrohr (2) verschieblich und feststellbar verbunden ist.3. Directional microphone according to claim 2, characterized in that the reflector (4) is provided at the opening corresponding to the tube diameter with a sleeve (5), via which it is connected to the interference tube (2) so that it can be moved and locked. 4. Richtmikrophon nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Reflektor (4) wenigstens angenähert der Form eines Parabolspiegels entspricht.4. directional microphone according to one of claims 1 to 3, characterized in that the reflector (4) corresponds at least approximately to the shape of a parabolic mirror. 5. Richtmikrophon nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Reflektor (4) in wenigstens zwei durch Hauptachsen (d1, d2) gelegte Ebenen unterschiedliche, vorzugsweise jedoch symmetrische Krümmungen und Größen aufweist.5. directional microphone according to one of claims 1 to 3, characterized in that the reflector (4) in at least two through main axes (d 1 , d 2 ) placed Levels have different, but preferably symmetrical curvatures and sizes. 6. Richtmikrophon nach Anspruch 1, dadurch gekennzeichnet, daß der Reflektor (7) eine zentrale öffnung aufweist, die wesentlich größer ist als dem Durchmesser des Interferenzrohres (2) entsprechend, und daß der Reflektor (7) über Stützelemente (8) im Bereich des freien Rohrendes mit dem Rohr (2) verbunden ist.6. directional microphone according to claim 1, characterized in that the reflector (7) has a central opening which is substantially larger than the diameter of the interference tube (2) accordingly, and that the reflector (7) via support elements (8) in the region of free pipe end is connected to the pipe (2). 7. Richtmikrophon nach Anspruch 6, dadurch gekennzeichnet, daß im Bereich des freien Rohrendes eine Manschette (5) verschieblich und feststellbar vorgesehen ist, an der die mit dem Reflektor (7) verbundenen Stützelemente (8) befestigt sind.7. directional microphone according to claim 6, characterized in that a sleeve (5) is slidably and securely provided in the region of the free tube end, to which the support elements (8) connected to the reflector (7) are fastened. 8. Richtmikrophon nach Anspruch 6 oder 7, dadurch gekennzeichnet, daß der Reflektor (7) einem ringförmigen Abschnitt eines Parabolspiegels entspricht.8. directional microphone according to claim 6 or 7, characterized in that the reflector (7) corresponds to an annular portion of a parabolic mirror. 9. Richtmikrophon nach Anspruch 6 oder 7, dadurch gekennzeichnet, daß der Reflektor (7) als ovaler Streifen ausgebildet ist, der in zwei durch Hauptachsen (dl,d2) gelegte Ebenen unterschiedliche, vorzugsweise jedoch symmetrische Krümmungen aufweist.9. directional microphone according to claim 6 or 7, characterized in that the reflector (7) is designed as an oval strip which has different, but preferably symmetrical curvatures in two planes laid by main axes (d l , d 2 ). 10. Richtmikrophon nach Anspruch 1, dadurch gekennzeichnet, daß die Reflektoranordnung einen größeren, zur Schallquelle auszurichtenden Reflektor (7') und konzentrisch hierzu einen kleineren, mit seiner reflektierenden Oberfläche gegen die Einspracheöffnung des_Interferenzrohres (2) gerichteten, die vom größeren Reflektor (7') gesammelten Schallwellen bündelnden und in die Einspracheöffnung umlenkenden Reflektor (9) aufweist.10. Directional microphone according to claim 1, characterized in that the reflector arrangement has a larger reflector to be aligned with the sound source (7 ') and concentrically a smaller one, with its reflecting surface directed against the mouth opening of the interference tube (2), which is directed away from the larger reflector (7' ) has collected sound waves that focus and deflect the reflector (9). 11. Richtmikrophon nach einem oder mehreren der Ansprüche 1 bis 10, dadurch gekennzeichnet, daß die Reflektoranordnung (4; 7; 7' und 9) lösbar mit dem Interferenzrohr (2) verbunden ist.11. directional microphone according to one or more of claims 1 to 10, characterized in that the reflector arrangement (4; 7; 7 'and 9) is detachably connected to the interference tube (2). 12. Richtmikrophon nach einem oder mehreren der Ansprüche 1 bis 10, dadurch gekennzeichnet, daß das Interferenzrohr (2) und die Reflektoranordnung (4; 7; 7' und 9) eine mechanische Einheit bilden12. Directional microphone according to one or more of claims 1 to 10, characterized in that the interference tube (2) and the reflector arrangement (4; 7; 7 'and 9) form a mechanical unit
EP79104634A 1978-11-23 1979-11-21 Directional microphone according to the interference principle Expired EP0011817B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT837578A AT358113B (en) 1978-11-23 1978-11-23 DIRECTIONAL MICROPHONE ACCORDING TO THE INTERFERENCE PRINCIPLE
AT8375/78 1978-11-23

Publications (2)

Publication Number Publication Date
EP0011817A1 true EP0011817A1 (en) 1980-06-11
EP0011817B1 EP0011817B1 (en) 1982-07-28

Family

ID=3604921

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79104634A Expired EP0011817B1 (en) 1978-11-23 1979-11-21 Directional microphone according to the interference principle

Country Status (8)

Country Link
US (1) US4264790A (en)
EP (1) EP0011817B1 (en)
JP (1) JPS55109100A (en)
AT (1) AT358113B (en)
AU (1) AU5285279A (en)
CA (1) CA1126388A (en)
DE (2) DE7932914U1 (en)
ES (1) ES486136A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1341162A1 (en) * 2002-02-27 2003-09-03 BSH Bosch und Siemens Hausgeräte GmbH Electric apparatus, in particular fume extracting hood

Families Citing this family (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4555598A (en) * 1983-09-21 1985-11-26 At&T Bell Laboratories Teleconferencing acoustic transducer
JPH0681352B2 (en) * 1985-11-19 1994-10-12 株式会社オ−デイオテクニカ Narrow directional microphone
JP2562295B2 (en) * 1985-11-19 1996-12-11 株式会社 オ−デイオテクニカ Narrow directional microphone
US4862507A (en) * 1987-01-16 1989-08-29 Shure Brothers, Inc. Microphone acoustical polar pattern converter
US5161250A (en) * 1990-04-12 1992-11-03 Play Action Inc. Single use radio device and method for using the same
US5513384A (en) * 1993-11-09 1996-04-30 Inner Ear Communications, Inc. System and method for providing multiple broadcasts of audio information to spectators
US5901232A (en) * 1996-09-03 1999-05-04 Gibbs; John Ho Sound system that determines the position of an external sound source and points a directional microphone/speaker towards it
US5820942A (en) * 1996-12-20 1998-10-13 Ag Associates Process for depositing a material on a substrate using light energy
US6278377B1 (en) 1999-08-25 2001-08-21 Donnelly Corporation Indicator for vehicle accessory
USD444143S1 (en) 1999-10-08 2001-06-26 Telex Communications, Inc. Microphone
EP1230739B1 (en) * 1999-11-19 2016-05-25 Gentex Corporation Vehicle accessory microphone
US7447320B2 (en) * 2001-02-14 2008-11-04 Gentex Corporation Vehicle accessory microphone
US8682005B2 (en) * 1999-11-19 2014-03-25 Gentex Corporation Vehicle accessory microphone
US7120261B1 (en) 1999-11-19 2006-10-10 Gentex Corporation Vehicle accessory microphone
AU2002250080A1 (en) * 2001-02-14 2002-08-28 Gentex Corporation Vehicle accessory microphone
JP2004075818A (en) * 2002-08-15 2004-03-11 Fuji Photo Film Co Ltd Ink composition and inkjet printing method
US20060269089A1 (en) * 2005-05-24 2006-11-30 Gieson David V Microphone shield
EP2257781A2 (en) * 2008-03-17 2010-12-08 Plastic Technologies, Inc. Method and apparatus for improved detection of holes in plastic containers
US8003878B2 (en) * 2008-08-05 2011-08-23 Gaynier David A Electroacoustic transducer system
US9014402B2 (en) 2012-05-16 2015-04-21 Klover Products, Inc. Acoustically isolated parabolic sound pickup assembly
USD733690S1 (en) 2013-10-30 2015-07-07 Kaotica Corporation Noise mitigating microphone attachment
US9992569B2 (en) 2014-05-30 2018-06-05 Paul D. Terpstra Camera-mountable acoustic collection assembly
US11268385B2 (en) 2019-10-07 2022-03-08 Nov Canada Ulc Hybrid core progressive cavity pump
US11813580B2 (en) 2020-09-02 2023-11-14 Nov Canada Ulc Static mixer suitable for additive manufacturing
DE112021000019T5 (en) * 2021-06-29 2023-03-02 Jiusheng (Tangshan) Technology Co., Ltd. Rear electrode plate of a recording microphone and recording microphone

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH196704A (en) * 1937-05-26 1938-03-31 Hugo Meier Listening device for detecting noises, in particular from approaching aircraft.
US2463762A (en) * 1941-11-14 1949-03-08 Automatic Elect Lab Electroacoustical transducer
DE1183134B (en) * 1961-12-08 1964-12-10 Heinrich Peiker microphone
DE1272375B (en) * 1964-12-01 1968-07-11 Akustische Interference microphone with a tube arranged in front of the membrane of the transducer system
US3444955A (en) * 1964-08-01 1969-05-20 Sennheiser Electronic Directional microphone with substantially frequency-independent directional characteristics

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2228886A (en) * 1938-10-31 1941-01-14 Rca Corp Electroacoustical apparatus
US3305043A (en) * 1965-03-08 1967-02-21 Charles E Pfund Acoustic communication device and toy

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH196704A (en) * 1937-05-26 1938-03-31 Hugo Meier Listening device for detecting noises, in particular from approaching aircraft.
US2463762A (en) * 1941-11-14 1949-03-08 Automatic Elect Lab Electroacoustical transducer
DE1183134B (en) * 1961-12-08 1964-12-10 Heinrich Peiker microphone
US3444955A (en) * 1964-08-01 1969-05-20 Sennheiser Electronic Directional microphone with substantially frequency-independent directional characteristics
DE1272375B (en) * 1964-12-01 1968-07-11 Akustische Interference microphone with a tube arranged in front of the membrane of the transducer system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1341162A1 (en) * 2002-02-27 2003-09-03 BSH Bosch und Siemens Hausgeräte GmbH Electric apparatus, in particular fume extracting hood

Also Published As

Publication number Publication date
AU5285279A (en) 1980-05-29
DE2963451D1 (en) 1982-09-16
ATA837578A (en) 1980-01-15
CA1126388A (en) 1982-06-22
US4264790A (en) 1981-04-28
JPS55109100A (en) 1980-08-21
ES486136A1 (en) 1980-06-16
AT358113B (en) 1980-08-25
DE7932914U1 (en) 1980-02-28
EP0011817B1 (en) 1982-07-28

Similar Documents

Publication Publication Date Title
EP0011817B1 (en) Directional microphone according to the interference principle
DE68907919T2 (en) ILLUMINATED UMBRELLA OR UMBRELLA.
DE202009010094U1 (en) Light directional grid and softbox
DE2902708C3 (en) Optical motion-dependent feedback system
DE2053089C3 (en) X-ray diaphragm
EP0184695B1 (en) Diaphragm for primary radiation in an x-ray examination apparatus
DE2836462A1 (en) Room surveillance sensor system - uses optical lens assembly to focus IR emissions onto detector stage
DE2254159C3 (en) Silencer for duct fan in underground operation
DE3629438C2 (en)
DE8511970U1 (en) Speaker box
AT5157U1 (en) ANTENNA HOUSING
DE2710311C3 (en) Optical equalizer for signal transmission via multimode optical waveguides
DE2834827A1 (en) Efficient solar reflector mirror - has set of hexagonal mirrors creating a field for solar energy absorber
DE2842255B2 (en) Traveling wave tube
EP0075884B1 (en) High tension shielding electrode
DE640496C (en) Reflector system for radiators of essentially linear extent
DE9418340U1 (en) Retaining ring for a film tube cover
EP0589154A1 (en) Antenna reflector
DE950489C (en) Tubular light source with screen
DE9014405U1 (en) Clamp for attaching a device to the top of a hollow mast and device with this clamp
DE19932514A1 (en) Solar cooker has paraboloid reflector possessing tensioning spokes, canopy, holder spokes, middle spoke and holder point
DE102021104822A1 (en) Sound wave guide system (wave guide) for sound reproduction in loudspeakers
DE678214C (en) Chimney or ventilation attachment
DE2746561A1 (en) TABLE WITH ASYMMETRIC LIGHTING LAMP
DE1142448B (en) Sound transmitter with shotgun

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): CH DE FR GB IT

17P Request for examination filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): CH DE FR GB IT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 19820728

REF Corresponds to:

Ref document number: 2963451

Country of ref document: DE

Date of ref document: 19820916

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19821028

Year of fee payment: 4

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CH

Effective date: 19821130

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19830802

GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19840731

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19881118

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT