JP2006311104A - Microphone system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microphone system that makes it possible to specify the direction of a target sound source and also auditorily recognize what sound is generated by the target sound source with simple constitution. <P>SOLUTION: The microphone system is equipped with a microphone probe 12 constituted by arranging six microphones M1 to M6 in pairs on respective (x), (y), and (z) axes, and an arithmetic processor 18 which specifies the direction of the target sound source from sound pressure data measured by those microphones M1 to M6 and selectively collects a sound from the direction of the target sound source by using the microphone probe 12. Consequently, it is made possible to auditorily confirm what sound is generated by the target sound source without additionally providing a zoom microphone. Consequently, the device constitution is simplified to increase portability, and precision and operation efficiency of selective sound collection are sufficiently increased. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a microphone system having an acoustic zoom function for selectively collecting sound from the direction of a target sound source.

  When performing abnormal sound analysis or noise countermeasures for automobiles, machines, etc., it is necessary to specify the direction of the target sound source after using a specific sound source as the target sound source. is there.

  Conventionally, as such a sound source exploration means, for example, as described in “Patent Document 1” and “Patent Document 2”, a target is obtained by measuring acoustic intensity using a microphone probe composed of a plurality of microphones. A sound source exploration device configured to specify the direction of a sound source is known.

  On the other hand, zoom microphones having an acoustic zoom function for selectively collecting sound from the direction of a target sound source have been known.

  For example, in “Patent Document 3”, an output signal from each of a pair of microphones arranged at a predetermined interval is added in a state where an output signal from one of the microphones is delayed for a predetermined time, A zoom microphone is described that is configured to selectively pick up sound from a particular direction.

Japanese Patent Laid-Open No. 5-288598 JP 2005-69774 A Japanese Patent Laid-Open No. 10-126876

  Although it is possible to specify the direction of the target sound source and numerically analyze the frequency component of the target sound source by using the conventional sound source exploration device, what kind of sound is actually generated from the target sound source? Therefore, there is a problem that abnormal sound analysis or the like cannot be performed in detail.

  As a method for realizing this, there can be considered a method of selectively collecting sound from the direction of the target sound source by attaching a zoom microphone to the sound source exploration device. There is a problem that it becomes complicated and portability deteriorates, and accuracy of selective sound collection and work efficiency cannot be sufficiently increased.

  The present invention has been made in view of such circumstances, and with a simple configuration, specifies the direction of the target sound source and confirms what sound is generated from the target sound source by hearing. An object of the present invention is to provide a microphone system that can

  The present invention achieves the above-mentioned object by using a microphone probe for sound source search to selectively collect sound from the direction of the target sound source.

That is, the microphone system according to the present invention is
A microphone probe in which a plurality of microphones are provided in a predetermined arrangement;
Sound source exploration means for specifying the direction of the target sound source from the sound pressure data measured in each microphone constituting the microphone probe;
And an acoustic zoom unit that selectively collects sound from the direction of the target sound source specified by the sound source search unit using the microphone probe.

  The number and arrangement of the “plurality of microphones” can identify the direction of the target sound source from the sound pressure data measured at each of these microphones, and can selectively collect the sound from the direction of the target sound source. If it is a thing, the specific number and arrangement | positioning will not be specifically limited.

  The specific configuration of each “microphone” such as the type, shape, and size is not particularly limited.

  If the “sound source searching means” is configured to specify the direction of the target sound source from the sound pressure data measured in each microphone constituting the microphone probe, the specific configuration for performing the specification is as follows. It is not particularly limited.

  If the “acoustic zoom means” is configured to selectively pick up sound from the direction of the target sound source specified by the sound source search means using a microphone probe, the selective sound pickup is performed. A specific configuration for performing the above is not particularly limited.

  As shown in the above configuration, the microphone system according to the present invention includes a microphone probe in which a plurality of microphones are provided in a predetermined arrangement, and a direction of a target sound source from sound pressure data measured in each microphone constituting the microphone probe. The sound source exploring means for identifying the sound source and the acoustic zoom means for selectively collecting the sound from the direction of the target sound source identified by the sound source exploring means using a microphone probe, The following effects can be obtained.

  That is, the sound intensity is “the energy flow that passes through the unit area per unit time” and has information on the size and direction, so that it is measured at each microphone constituting the microphone probe as in the present invention. The direction of the target sound source can be specified by calculating the sound intensity from the sound pressure data obtained by the sound source search means. And what kind of sound is generated from the target sound source by selectively collecting the sound from the direction of the target sound source specified by the sound source exploration means using the microphone probe by the acoustic zoom means? Can be confirmed by hearing. In addition, this can be realized without the need for an additional zoom microphone, so that the device configuration can be simplified and the portability can be improved, and the accuracy and work efficiency of selective sound collection can be sufficiently increased. it can.

  As described above, according to the present invention, the direction of the target sound source can be specified with a simple configuration, and what kind of sound is generated from the target sound source can be confirmed by hearing.

  In the above configuration, as the plurality of microphones constituting the microphone probe, the first and second microphones disposed at positions symmetrical with respect to the reference axis in a plane orthogonal to the predetermined reference axis, and the first microphone in the plane. If the configuration includes the third and fourth microphones arranged symmetrically with respect to the reference axis on a straight line orthogonal to the straight line connecting the first and second microphones, these two arranged in a cross shape. With the set of microphones, a two-dimensional component along the plane of the sound intensity and the direction of the sound source can be calculated with the intersection as a measurement point.

  In other words, if the target sound source can be considered to be in the plane (for example, if the target sound source is an attendee surrounding a large conference table or a competition player in an outdoor ground). Since it is not necessary to specify the sound source three-dimensionally and it is sufficient to specify it two-dimensionally, by using a microphone probe provided with two sets of microphones arranged in a cross like this, with a very simple configuration, The direction of the target sound source can be specified, and what kind of sound is generated from the target sound source can be confirmed by hearing.

  In this case, the interval between the “first and second microphones” and the interval between the “third and fourth microphones” may be set to the same value or different values. The specific values of the interval between the “first and second microphones” and the interval between the “third and fourth microphones” are not particularly limited.

  In such a case, the acoustic zoom means is a state in which the output signals from the first and second microphones are delayed by a predetermined time based on the information on the direction of the target sound source. If the configuration is such that the sound from the direction of the target sound source is emphasized, it is possible to visually confirm what sound is generated from the target sound source with a simple circuit configuration.

  At this time, as the acoustic zoom means, the output signals from the third and fourth microphones are added in a state where the output signal from one microphone is delayed for a predetermined time based on the information on the direction of the target sound source. If the configuration is such that the sound from the direction of the target sound source is emphasized, the sound from the direction of the target sound source can be emphasized twice, and the selective sound collection can be performed more effectively.

  Further, in this case, if the microphone probe is configured to include the fifth and sixth microphones arranged at positions symmetrical with respect to the plane on the reference axis, each of the fifth and sixth microphones is provided. The direction of the target sound source can be identified three-dimensionally from the sound pressure data measured in step 1 and the sound pressure data measured in each of the first to fourth microphones. Since only the sound from the sound source can be pinpointed and emphasized, what kind of sound is generated from the target sound source can be more clearly confirmed by hearing.

  In the case where the fifth and sixth microphones are provided as the microphone probes as described above, the output signals from the fifth and sixth microphones are used as acoustic zoom means based on the information on the direction of the target sound source. If the output from the microphone is added in a state delayed for a predetermined time, and the sound from the direction of the target sound source is emphasized, the sound from the direction of the target sound source can be triple-enhanced, The selective sound collection can be performed with higher accuracy.

  By the way, in the microphone system according to the present invention, it is of course possible to use the microphone probe in a fixed state. However, based on the information on the direction of the target sound source, the microphone probe is moved to change the direction of the reference axis to the target sound source. It is also possible to match with the direction of. In this case, the two sets of microphones (that is, the first to fourth microphones) arranged in a cross shape can be arranged in a plane orthogonal to the direction of the target sound source (and the fifth and fourth microphones). If a sixth microphone is provided, these can be arranged so as to coincide with the direction of the target sound source), so that it is easier to selectively collect sound from the direction of the target sound source by the acoustic zoom means. Can be performed with high accuracy. As a result, it is possible to efficiently perform a rescue operation in a disaster using the microphone system according to the present invention.

  At that time, the measurer may move the microphone probe so that the direction of the reference axis coincides with the direction of the target sound source, or the microphone system includes a rotation adjusting means for rotating the microphone probe. The microphone probe may be moved by the rotation adjusting means so that the direction of the reference axis coincides with the direction of the target sound source.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a microphone system according to an embodiment of the present invention.

  As shown in the figure, the microphone system 10 according to the present embodiment includes a microphone probe 12, a probe support 14, an amplifier 16, and an arithmetic processing unit 18, and an acoustic signal at a measurement point O of the microphone probe 12 is shown. The direction of the target sound source is specified by measuring the intensity, and the sound from the direction of the target sound source is selectively collected using the microphone probe 12.

  FIG. 2 is a perspective view showing the microphone probe 12.

  As shown in the figure, the microphone probe 12 includes six omnidirectional microphones M1 to M6, two on each of the x-axis, y-axis, and z-axis with the measurement point O as the origin. Has been placed. At this time, as each of the microphones M1 to M6, a small electret condenser microphone (for example, about 3 to 6 mm in diameter) is used.

  The microphones M1 and M2 are arranged opposite to each other at a symmetric position with respect to the measurement point O on the x axis constituting the reference axis of the microphone probe 12, and the microphones M3 and M4 are symmetric with respect to the measurement point O on the y axis. The microphones M5 and M6 are arranged opposite to each other at positions symmetrical with respect to the measurement point O on the z axis.

  These six microphones M1 to M6 are all arranged at a position equidistant from the measurement point O (for example, a position about 15 mm away from the origin O). In addition, the six microphones M1 to M6 have tip portions of three pairs of shaft portions of the shaft-shaped support member 20 formed in a three-dimensional cross shape so as to extend in the axial directions of the x-axis, y-axis, and z-axis. Are fixedly connected to each other. At this time, a plurality of sound holes 20a are formed at equal intervals in the circumferential direction between the tip portions of the shaft portions of the shaft-shaped support member 20 and the microphones M1 to M6. .

  The microphone probe 12 moves in a direction away from the measurement point O along the x axis from one microphone M2 of the pair of microphones M1 and M2 arranged on the x axis (hereinafter, this direction is referred to as “rearward”). An extending probe support shaft 22 is fixed. The probe support shaft 22 is configured as a shaft-like member having a slightly smaller diameter than each shaft portion of the shaft-like support member 20, and six groove portions 22 a extending in the x-axis direction are formed on the peripheral surface thereof. . In each of these groove portions 22a, a cord 24 extending from each of the microphones M1 to M6 is accommodated. The microphone probe 12 is inserted and fixed to the fixing sleeve 14 </ b> A of the probe support 14 on the probe support shaft 22.

  As shown in FIG. 1, the probe support 14 includes the fixing sleeve 14A, a main body portion 14B that supports the fixing sleeve 14A, and a tripod 14C that extends downward from the main body portion 14B. It is designed to be used in a state where it is installed in the same place.

  In the microphone system 10 according to the present embodiment, the sound pressure data measured by the six microphones M1 to M6 are amplified by the amplifier 16 and then input to the arithmetic processing unit 18. The amplifier 16 and the arithmetic processing unit 18 are mounted on the main body 14B of the probe support 14.

  In the arithmetic processing unit 18, after AD conversion of the input data in the AD converter 18A, the sound intensity at the measurement point O is calculated by performing data analysis based on a predetermined algorithm in the arithmetic processing unit 18B, The direction of the target sound source and its radiated sound power are calculated from the calculation result.

  That is, in the arithmetic processing unit 18B, the direction of the target sound source and the direction of the target sound source are calculated based on the sound intensity calculation result based on the sound pressure data measured by the two sets of microphones M3, M4 and M5, M6 located on the yz plane. While calculating a two-dimensional component along the yz plane of the sound intensity at the measurement point O, the sound intensity based on the sound pressure data measured by the pair of microphones M1 and M2 located on the x-axis is calculated. Based on the calculation result, the direction of the target sound source and the component along the x-axis of the sound intensity at the measurement point O are calculated, and the direction of the target sound source and the sound intensity at the measurement point O are calculated three-dimensionally. It is like that.

  FIG. 4 is a diagram showing the sound intensity when sound source search is performed using an 800 Hz sound source as a target sound source.

  The upper graph in the figure shows the x-axis component of the sound intensity calculated from the sound pressure data (waveform data indicated by CH1 and CH2 in the figure) measured by the microphones M1 and M2, and the upper graph in the figure. Indicates the y-axis component of the sound intensity calculated from the sound pressure data measured by the microphones M3 and M4 (waveform data indicated by CH3 and CH4 in the figure), and the lower graph in the figure shows the microphone M5, The z-axis component of the sound intensity calculated from the sound pressure data measured by M6 (waveform data indicated by CH5 and CH6 in the figure) is shown.

  As is apparent from these three graphs, the x-axis component and the z-axis component of the sound intensity around 800 Hz are positive values, whereas the y-axis component is a negative value. The absolute values are almost the same. From these values, the target sound source is in the positive direction with respect to the measurement point O in the x-axis direction and the z-axis direction, in the negative direction with respect to the y-axis direction, and inclined at substantially the same angle from each axis. You can see that it is in the direction. As a result, it is specified that the target sound source exists in the direction of about 45 ° obliquely forward with respect to the measurement point O.

  In the arithmetic processing unit 18, the sound from the direction of the target sound source specified in this way is selectively collected using the microphone probe 12. The arithmetic processing unit 18 outputs the selectively collected sound from the direction of the target sound source to a speaker or headphones (not shown). At that time, the sound from the direction of the target sound source that has been selectively collected may be recorded in a recording means (not shown).

  FIG. 3 is a diagram illustrating a specific configuration for performing this selective sound collection, taking as an example a case where sound from a target sound source in the xz plane is collected by a pair of microphones M5 and M6. is there.

  As shown in the figure, in the arithmetic processing unit 18B of the arithmetic processing unit 18, the output signal X5 (t) from one microphone M5 among the output signals from the pair of microphones M5 and M6 is delayed by the delay unit 32. The output signal X6 (t) from the other microphone M6 is directly input to the adder 34 after being delayed by a predetermined time τ, and both output signals X5 (t), X6 (t) is added.

  Here, as shown in the figure, when the target sound source is in the direction inclined by the angle θ toward the microphone M5 with respect to the front in the x-axis direction, the sound wave (plane wave) from the direction of the target sound source is collected. Think about the case. In the figure, a thick arrow represents the traveling direction of a sound wave, and a plurality of broken lines orthogonal to these represent a wavefront.

  At this time, the sound wave first reaches the microphone M5, and then proceeds further by the distance ξ shown in the figure and reaches the microphone M6. As a result, the output signal X6 (t) from the microphone M6 becomes a signal delayed by the time τ in which the sound wave travels the distance ξ, as compared with the output signal X5 (t) from the microphone M5. This time difference τ is expressed by τ = ξ / c (c: sound velocity), and the distance ξ is expressed by ξ = d · sin θ, where d is the distance between the microphones M5 and M6. Therefore, the time difference τ is τ = d · sin θ / c, which is a value depending on the incident direction θ of the sound wave.

  Therefore, if the time difference τ is set as the delay time in the delay device 32, the delayed output signal X5 (t) is in phase with the output signal X6 (t) on the time axis. On the other hand, sound waves coming from directions other than the direction of the target sound source are collected by the microphones M5 and M6 with a time difference different from the time difference τ, so that they are not in phase. Then, the in-phase output signals X5 (t) and X6 (t) are added by the adder 34, thereby enhancing the sound from the direction of the target sound source.

  Even when the target sound source is at a position deviating from the xz plane, the angle θ is used as a component obtained by projecting the angle between the direction of the target sound source and the x axis on the xz plane, and the delay addition process is performed. Then, the sound from the direction of the target sound source can be emphasized.

  In the arithmetic processing unit 18B, the delay addition process is similarly performed for the other two sets of microphones M1, M2, and M3, M4. As a result, the sound from the direction of the target sound source is emphasized three times, and the selective sound collection of the sound from the direction of the target sound source is performed more effectively.

  As described above in detail, the microphone system 10 according to the present embodiment includes the microphone probe 12 in which six microphones M1 to M6 are provided in a predetermined arrangement, and the microphones M1 to M6 constituting the microphone probe 12. The configuration includes an arithmetic processing unit 18 that specifies the direction of the target sound source from the measured sound pressure data and selectively collects sound from the direction of the target sound source using the microphone probe 12. Therefore, it is possible to visually confirm what kind of sound is generated from the target sound source without the need for a zoom microphone. As a result, the apparatus configuration can be simplified and the portability can be improved, and the accuracy and work efficiency of selective sound collection can be sufficiently increased.

  In addition, the microphone system 10 according to the present embodiment includes the microphones M1 and M2 that are arranged symmetrically with respect to the measurement point O on the x-axis, and the measurement on the y-axis, as a plurality of microphones constituting the microphone probe 12. Since the microphones M3 and M4 are arranged symmetrically with respect to the point O, and the microphones M5 and M6 are arranged symmetrically with respect to the measurement point O on the z axis, the configuration is a three-dimensional cross. With the three sets of arranged microphones M1 to M6, the sound intensity at the measurement point O and the direction of the sound source can be calculated three-dimensionally.

  Then, in the microphone system 10 according to the present embodiment, the output signal from the microphones M1 and M2 is output from the one microphone M1 (or M2) based on the information on the direction of the target sound source. Are added in a delayed state for a predetermined time, so that the sound from the direction of the target sound source is emphasized, and the output signal from the microphones M3 and M4 is converted into one microphone M3 ( Alternatively, the output signal from M4) is added in a state delayed for a predetermined time, thereby emphasizing the sound from the direction of the target sound source, and further using the output signals from the microphones M5 and M6 as information on the direction of the target sound source. Based on this, the output signal from one microphone M5 (or M6) is added in a state delayed for a predetermined time, thereby obtaining the target sound source. Since the sound from the direction is emphasized, the sound from the direction of the target sound source can be emphasized three times by a simple circuit configuration, and the selective sound collection can be performed extremely effectively. it can.

  Moreover, at that time, only the sound from the direction of the target sound source specified three-dimensionally can be pinpointed and emphasized, so what kind of sound is generated from this target sound source. It can be confirmed very clearly by hearing.

  In the above-described embodiment, the case where the microphone probe 12 is used in a state where it is installed on the floor surface or the like has been described. However, the microphone probe 12 may be carried by a measurer. Thus, when the microphone probe 12 is carried and used, the operability of the microphone probe 12 can be improved by providing a grip portion or the like for gripping with a hand instead of the tripod 14C of the probe support 14. be able to.

  Further, when the microphone probe 12 is carried and used in this way, the direction of the x-axis that is the reference axis line can be made to coincide with the direction of the target sound source.

  For example, when the target sound source does not exist on the x-axis, the microphone probe 12 is moved so that the direction of the x-axis is directed toward the target sound source while referring to the sound intensity graph as shown in FIG. It is possible to do so. In this case, if the microphone probe 12 is moved so that the acoustic intensity near 800 Hz is zero in the middle graph and the lower graph in the same figure, the direction of the x-axis becomes the direction of the target sound source. Can be matched.

  At that time, the sound from the direction of the target sound source picked up by the microphone system 10 is monitored by a speaker or headphones, so that the operation of turning the direction of the x-axis toward the direction of the target sound source can be easily performed using hearing. It becomes possible.

  FIG. 5 is a diagram showing the sound intensity when the direction of the x-axis, which is the reference axis, is matched with the direction of the target sound source in this way.

  In a state where the direction of the x-axis coincides with the direction of the target sound source, as shown in the graph in the upper part of the figure, the x-axis component of the sound intensity calculated from the sound pressure data measured by the microphones M1 and M2 is 800 Hz. , The y-axis component of the sound intensity calculated from the sound pressure data measured by the microphones M3 and M4 and the microphones M5 and M6 as shown in the middle and lower graphs of FIG. The z-axis component of the sound intensity calculated from the measured sound pressure data has a value at 800 Hz of zero.

  By making the direction of the x axis coincide with the direction of the target sound source in this way, the two sets of microphones M3, M4 and M5, M6 arranged in a cross shape are arranged in a plane orthogonal to the direction of the target sound source. Since the remaining pair of microphones M1 and M2 can be arranged so as to coincide with the direction of the target sound source, the delay addition process in the arithmetic processing unit 18B can be performed easily and accurately. Can be collected accurately with simpler calculation. As a result, rescue operations and the like during a disaster can be efficiently performed using the microphone system 10.

  Instead of having the measurer manually perform the operation of making the direction of the x-axis of the microphone probe 12 coincide with the direction of the target sound source in this way, the actuator 36 is operated as in the microphone system 110 shown in FIG. It is also possible to use the microphone probe 12 automatically by rotating it.

  In other words, in the microphone system 110 shown in the figure, the probe support 14 is supported on the body 14B of the fixing sleeve 14A via the actuator 36, and the microphone probe 12 is controlled by driving the actuator 36. The direction of the x-axis is made to coincide with the direction of the target sound source. The drive control signal at that time is input from the arithmetic processing unit 18 to the actuator 36 via the drive circuit 38 in accordance with the value of each axis component of the sound intensity.

  In the above-described embodiment, the case where sound source search is performed using a sound source of 800 Hz as a target sound source has been described as an example. However, the above implementation is also performed when a sound source of a frequency other than this is used as a target sound source. It is possible to search for a sound source in the same manner as in the case of the form.

  In the above-described embodiment, the three microphones M1 to M6 are described as being arranged at equidistant positions from the measurement point O. However, the distance from the measurement point O is different for each group. It is also possible to set to.

  Furthermore, in the above embodiment, the description has been given assuming that the three sets of microphones M1 to M6 are arranged in a three-dimensional cross shape. However, depending on the purpose of use of the microphone system, two sets of the three sets of microphones M1 to M6 may be used. A configuration in which the microphones are arranged in a cross shape is also possible.

  For example, if the target sound source can be considered to be in the plane, such as an attendee who surrounds a large conference table or a competition player in an outdoor ground, etc. Since it is not necessary to specify the sound source three-dimensionally and it is sufficient to specify it two-dimensionally, by using a microphone probe provided with two sets of microphones arranged in a cross like this, with a very simple configuration, The direction of the target sound source can be specified, and what kind of sound is generated from the target sound source can be confirmed by hearing.

The block diagram which shows the microphone system which concerns on one Embodiment of this invention. The perspective view which shows the microphone probe of the said microphone system The figure which shows the specific structure for performing selective sound collection in the said microphone system The figure which shows the sound intensity when the sound source search is performed by using the above-mentioned microphone system as the target sound source of the 800 Hz sound source. The figure which shows the sound intensity when the direction of the reference axis of the above microphone probe matches the direction of the target sound source The same figure as FIG. 1 which shows the structure of the microphone system which concerns on the modification of the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,110 Microphone system 12 Microphone probe 14 Probe support 14A Fixing sleeve 14B Body part 14C Tripod 16 Amplifier 18 Arithmetic processing unit 18A AD converter 18B Arithmetic processing part 20 Axis support member 20a Sound hole 22 Probe support shaft 22a Groove part 24 Code 32 delay device 34 adder 36 actuator 38 drive circuit M1 microphone (fifth microphone)
M2 microphone (sixth microphone)
M3 microphone (first microphone)
M4 microphone (second microphone)
M5 microphone (third microphone)
M6 microphone (fourth microphone)
O Measuring point

Claims (7)

A microphone probe in which a plurality of microphones are provided in a predetermined arrangement;
Sound source exploration means for specifying the direction of the target sound source from the sound pressure data measured in each microphone constituting the microphone probe;
A microphone system comprising: an acoustic zoom unit that selectively collects sound from the direction of the target sound source specified by the sound source search unit using the microphone probe.   A straight line connecting the first and second microphones in the plane and the first and second microphones arranged at positions symmetrical to the reference axis in a plane orthogonal to the predetermined reference axis. The microphone system according to claim 1, further comprising third and fourth microphones arranged at positions symmetrical with respect to the reference axis on a straight line perpendicular to the reference axis.   The acoustic zoom means adds the output signals from the first and second microphones in a state where the output signal from one microphone is delayed for a predetermined time based on the information on the direction of the target sound source, The microphone system according to claim 2, wherein the microphone system is configured to emphasize sound from the direction of the target sound source.   The acoustic zoom means adds the output signals from the third and fourth microphones in a state where the output signal from one microphone is delayed for a predetermined time based on the information on the direction of the target sound source, The microphone system according to claim 3, wherein the microphone system is configured to emphasize sound from the direction of the target sound source.   5. The microphone system according to claim 2, wherein the microphone probe includes fifth and sixth microphones arranged at positions symmetrical with respect to the plane on the reference axis.   The acoustic zoom means adds the output signals from the fifth and sixth microphones in a state where the output signal from one microphone is delayed for a predetermined time based on the information on the direction of the target sound source, The microphone system according to claim 5, wherein the microphone system is configured to emphasize sound from the direction of the target sound source.   The microphone system according to any one of claims 2 to 6, further comprising rotation adjusting means for rotating the microphone probe so that the direction of the reference axis coincides with the direction of the target sound source.

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