Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JP2012244511 An object of the present invention is to provide a narrow directional microphone and an adapter for a narrow directional microphone capable of obtaining high directivity even at low frequencies without lengthening an acoustic tube. A microphone unit (4), a first acoustic tube (2) in which a plurality of first openings (22) are formed in a peripheral wall along an axial direction and the microphone unit (4) is mounted inside, a first acoustic tube (2) And a first acoustic resistance material 3 for closing the opening 22 of the narrow directional microphone 1. The narrow directional microphone 1 further includes a second acoustic tube 6 which is placed on the outer side of the first acoustic tube 2 with a predetermined gap, and the second acoustic tube 6 has a plurality of second acoustic tubes 6 along the axial direction on the peripheral wall. The opening 62 is formed, and a second acoustic resistance material is provided to close the second opening 62 of the second acoustic tube 6. [Selected figure] Figure 1 Narrow directional microphone and adapter for narrow directional microphone [0001] The present invention relates to a narrow directional microphone and an adapter for a narrow directional microphone in which a microphone unit is mounted in an acoustic tube. More specifically, the present invention relates to a narrow directional microphone and an adapter for a narrow directional microphone that can obtain high directivity even at low frequencies without lengthening an acoustic tube. [0002] 03-05-2019 1 As an example of a conventional narrow directional microphone using an acoustic tube, an acoustic tube made of a metal tube or the like is used, and an opening such as a slit is provided on a peripheral wall of the acoustic tube in the central axis direction There is one in which an acoustic resistor is attached to a peripheral wall of an acoustic tube and the opening is covered with the acoustic resistor. The narrow directional microphone having such a configuration achieves narrow directivity by causing the sound wave coming around from the front end opening of the acoustic tube to interfere with the sound wave guided from the peripheral wall opening of the acoustic tube through the acoustic resistor. . [0003] As a narrow directional microphone, as shown in Patent Document 1, one using an elongated acoustic tube is known. In this method, the microphone unit is mounted on the inner peripheral side of one end of the acoustic tube, and the sound wave entering from the opening at the front end which is the other end of the acoustic tube is detected by the microphone unit and converted into an audio signal. [0004] Specifically, the above-mentioned acoustic tube is an interference pipe which is made of metal such as aluminum and whose axial direction both ends are open. An opening for resistance is provided. An acoustic resistance material made of non-woven fabric or the like is attached to the circumferential surface of the interference pipe so as to cover these openings. [0005] The plurality of openings are also formed in portions spaced 180 degrees in the circumferential direction, and the acoustic resistance material is similarly attached. A plurality of axially elongated holes are provided at intervals in the circumferential direction at intervals of 90 degrees in the circumferential direction with respect to the row of the openings and on the circumferential surface from the front end to the rear end . 03-05-2019 2 [0006] A diaphragm made of a thin film of synthetic resin such as vinylidene fluoride is attached to the interference pipe so as to cover these long holes. [0007] The outline of another example of the conventional narrow directional microphone using the acoustic tube as described above will be described with reference to the drawings. As shown in FIG. 3, the narrow directional microphone 1 includes an acoustic tube 2, an acoustic resistance material 3, a microphone unit 4, and a grip 5. The acoustic tube 2 is an elongated cylindrical member made of metal or the like, and a plurality of openings 22 are formed in the peripheral wall thereof in parallel with the central axis of the acoustic tube. [0008] In FIG. 3, assuming that the left end of the acoustic tube 2 is the front end and the right end is the rear end, the microphone unit 4 is disposed on the inner peripheral side of the rear end. An acoustic resistance material 3 is attached to the peripheral wall of the acoustic tube 2 so as to cover the opening 22. The acoustic tube 2 is open at both ends in the longitudinal direction. An opening 24 at the front end of the acoustic tube introduces sound waves from the front. A cylindrical grip 5 is integrally connected to the rear end of the acoustic tube 2 following the acoustic tube 2. [0009] Japanese Patent Application Laid-Open No. 62-118697 [0010] As described above, the directivity of the narrow directional microphone is generated by the interference with the sound wave by the acoustic tube, and therefore, is influenced by the wavelength of the sound wave and the length of the acoustic tube. 03-05-2019 3 Specifically, narrow directivity can be obtained to a low frequency band by using a long acoustic pipe, but narrow directivity can be obtained only in a high frequency band when using a short acoustic pipe. [0011] Therefore, narrow directivity can be obtained up to a low frequency band if a long acoustic tube is used, but if the acoustic tube is long, the total length of the microphone becomes long, which makes it inconvenient to handle. [0012] Also, high narrow directivity may be required even at the expense of frequency characteristics. [0013] The present invention has been made in view of the above problems, and an object of the present invention is to obtain a narrow directional microphone capable of obtaining narrow directivity to a low frequency band without lengthening an acoustic tube. [0014] Another object of the present invention is to provide an adapter for a narrow directional microphone that can cope with the case where high narrow directivity is required even at the expense of frequency characteristics. [0015] The narrow directional microphone according to the present invention includes a microphone unit, a first acoustic tube having a plurality of first openings formed in the peripheral wall along the axial direction and in which the microphone unit is mounted, and an acoustic tube. A narrow directional microphone comprising: a first acoustic resistance member closing an opening, the narrow directional microphone further comprising: a second acoustic tube which is covered on the outside of the first acoustic tube with a predetermined gap, 2) The main feature of the acoustic tube is that a plurality of second openings are formed along the axial direction in the peripheral wall, and the second acoustic resistance material is used to close the second opening of the second acoustic tube. I assume. [0016] 03-05-2019 4 According to the present invention, narrow directivity can be obtained to a low frequency band without lengthening the acoustic tube. Further, according to the present invention, it is possible to cope with the case where high narrow directivity is required even at the expense of frequency characteristics. [0017] FIG. 1 is a partial cross-sectional side view showing an embodiment of a narrow directional microphone according to the present invention. It is principal part sectional drawing of the said narrow directivity microphone. The 2nd acoustic pipe used for said narrow directivity microphone is shown, (A) is a side view, (B) is a longitudinal cross-sectional view, (C) is a front view. It is a principal part expanded sectional view of the above-mentioned 2nd sound pipe. It is principal part sectional drawing which shows the state which removed the 2nd acoustic pipe from the said narrow directivity microphone. It is a side view showing an example of the conventional narrow directivity microphone unit. [0018] Hereinafter, embodiments of the narrow directional microphone according to the present invention will be described with reference to the drawings. The same components as those of the conventional narrow directional microphone are denoted by the same reference numerals. [0019] 03-05-2019 5 As shown in FIGS. 1 to 5, the narrow directional microphone includes a first acoustic pipe 2, a first acoustic resistance material 3, a second acoustic pipe 6, a second acoustic resistance material 66, a microphone unit 4, a grip 5, an outer It has a cover 7. [0020] The first acoustic tube 2 is an elongated cylindrical member made of metal or the like, and a plurality of first openings 22 are formed in the peripheral wall thereof in parallel with the central axis of the acoustic tube. [0021] The first acoustic resistance material 3 is attached to the peripheral wall of the first acoustic tube 2 so as to cover the first opening 22. Both ends in the longitudinal direction of the first acoustic tube 2 are open. An opening 24 at the front end of the first acoustic tube 2 introduces sound waves from the front. A cylindrical grip 5 is integrally coupled to the rear end of the first acoustic tube 2 following the first acoustic tube 2. The outer side of the first acoustic tube 2 and the grip 5 is covered with a cylindrical outer cover 7 having a plurality of openings 72 through which sound waves pass on the side walls. [0022] The second acoustic tube 6 is an elongated cylindrical member having a diameter larger than that of the first acoustic tube, and like the first acoustic tube 2, a plurality of slit-like second openings parallel to the central axis of the acoustic tube on its peripheral wall 62 are formed. [0023] The second acoustic tube 6 is provided in the narrow directional microphone 1 so as to cover the outer cover 7 at a predetermined interval. 03-05-2019 6 Thereby, a predetermined space is formed between the second acoustic pipe 6 and the first acoustic pipe 2 located inside the outer cover 7, and this space becomes the air chamber 8. At the end of the narrow directional microphone 1 opposite to the sound collecting direction, the gasket 64 establishes close contact between the second acoustic pipe 6 and the first acoustic pipe 2. Among the plurality of first openings 22 of the first acoustic tube 2, the first opening 222 opposite to the sound collecting direction of the narrow directional microphone 1 is covered with the second acoustic tube 6 in order to prevent resonance. Absent. The microphone unit 4 is mounted inside the portion of the first acoustic tube 2 not covered by the second acoustic tube 6. [0024] A second acoustic resistance material 66 is attached to the peripheral wall of the second acoustic tube 6 so as to cover the second opening 62. Both ends in the longitudinal direction of the second acoustic tube 6 are open. [0025] In the narrow directional microphone 1 formed in this manner, sound waves from the front (the opening direction of the front end of the second acoustic tube 6) are guided into the opening 24 at the front end of the first acoustic tube 2 and are almost attenuated. Without reaching the diaphragm of the microphone unit 4. [0026] On the other hand, sound waves from angles other than the front, that is, sound waves that enter from the second opening 62 of the second acoustic tube 6 and pass through the second acoustic resistance material 66 are between the second acoustic tube 6 and the first acoustic tube 2 It enters into the air chamber 8 formed. Then, the sound wave that has entered the air chamber 8 enters the inside of the first acoustic tube 2 via the first acoustic resistance 3 of the inner first acoustic tube 2. Sound waves from angles other than the front of the first acoustic tube 2 also enter the air chamber 8 from the front of the first acoustic tube 2. Since there is a phase difference between the sound waves entering the air chamber 8 from the front and the sound waves entering the air chamber 8 from the second opening 62, these sound waves interfere with each other. Fit. And sound waves from 03-05-2019 7 angles other than the front are attenuated by this interference. [0027] As described above, according to the narrow directional microphone according to the present invention, sound waves from angles other than the front are attenuated by interference, so that the conventional narrow directivity can be obtained even at low frequencies without increasing the length of the acoustic tube. Narrow directivity higher than a microphone can be obtained. The narrow directional microphone according to the present invention is inferior in frequency characteristics to the conventional narrow directional microphone in which the acoustic tube is sufficiently long. However, it can be suitably used when high narrow directivity is required even at the expense of frequency characteristics. [0028] When the first acoustic pipe and the second acoustic pipe are integrated by adhesion, the second acoustic pipe can not be removed. However, by attaching the second acoustic tube as a removable adapter to a conventional narrow directional microphone not provided with the second acoustic tube, the same effect as the narrow directional microphone according to the present invention can be provided. it can. [0029] For example, the second acoustic tube can be attached as an adapter to a narrow directional microphone as described in Patent Document 1, and the narrow directivity can be further enhanced. If the second acoustic tube is configured to be attachable to and detachable from a narrow directional microphone as an adapter, the adapter is attached when higher narrow directivity is required, and the frequency characteristic is considered more important than the narrow directivity. In this case, the adapter can be removed and used. [0030] DESCRIPTION OF SYMBOLS 1 narrow directivity microphone 2 1st acoustic tube 22 1st aperture 3 1st acoustic resistance material 4 microphone unit 5 grip 6 2nd acoustic tube 62 2nd aperture 64 gasket 66 2nd acoustic resistance 7 outer cover 72 aperture 8 air chamber 03-05-2019 8 03-05-2019 9
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