JP2007214914A - Sound collection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound collection apparatus capable of carrying out more diversified sound collection. <P>SOLUTION: The sound collection apparatus 1 is characterized in including: two single directivity microphones 2, the directivity axis of which is turnable around two rotary shafts a, b in parallel with each other; and support parts 21 for supporting the single directivity microphones 2 in a way of being movable for a prescribed interval on straight lines tying the two rotary shafts a, b. Through the configuration above, since the two single directivity microphones 2 are provided turnably around the two rotary shafts a, b in parallel with each other, the direction of the principal axis can individually be revised thereby allowing the sound collection apparatus 1 to cope with the diversified sound collection systems. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a sound collection device capable of collecting sound by a plurality of types of sound collection methods using a plurality of microphones whose main axes can be changed.

Conventionally, a sound collection device using a plurality of microphones capable of changing the sound collection angle has been known. For example, Patent Document 1 discloses a sound collection device that can change a sound collection angle of these microphones by rotating a microphone unit including a plurality of microphones around a rotation axis. In this sound collection device, the sound signal processing applied to the collected sound signal is changed according to the sound collection angle of the microphone, and thereby the directivity can be changed.
JP 2005-277832 A

  In the conventional microphone described above, since the plurality of microphones rotate integrally, it was not possible to individually set different sound collection angles. In addition, the positional relationship between the microphones cannot be changed, and the rotation of each microphone is in one direction, and variations in the directivity of each microphone are scarce.

  For this reason, it was not possible to properly collect sound corresponding to various sound collecting methods.

  In order to solve the above-described problems, an object of the present invention is to provide a sound collecting device that can suitably perform various kinds of sound collecting.

  In order to solve the above problems, the present invention employs the following means.

  (1) The present invention according to the first means for solving the problems includes two unidirectional microphones provided so as to be rotatable about two rotation axes parallel to each other, and the two unidirectional microphones. A sound collecting device comprising: a supporting portion that supports a rotating shaft of a directional microphone so as to be movable in a predetermined section on a straight line connecting the rotating shafts to each other.

  According to the configuration of the present invention, since the two unidirectional microphones are provided so as to be rotatable around two rotation axes parallel to each other, the directions of the main shafts can be individually changed. It is possible to make the sound collection device compatible with various sound collection methods.

  Moreover, the positional relationship between suitable unidirectional microphones differs depending on the various sound collection methods. In the present invention, two unidirectional microphones are supported so as to be movable in a predetermined section on a straight line connecting the rotation axes of these unidirectional microphones. For this reason, by moving the unidirectional microphone in a predetermined section, it is possible to easily place the two unidirectional microphones in a positional relationship suitable for each sound collection method. As a result, it is possible to appropriately collect sound by various sound collecting methods.

  (2) According to the present invention, in the sound collecting device described above, a bidirectional microphone that is provided on the straight line so that the straight line and the directivity axis are at right angles, and the bidirectional microphone is the rotation axis. And a second support portion that is movably supported in a parallel direction.

  According to the configuration of the present invention, it is possible to perform various sound collections using a bi-directional microphone and a unidirectional microphone. At the same time, the position of the bidirectional microphone can be moved in the direction parallel to the rotation axis by the second support portion. For this reason, when housing the sound collecting device, it is possible to make the sound collecting device compact by arranging the bi-directional microphone in a position aligned with the unidirectional microphone.

  In addition, when collecting sound, it becomes possible to place a bidirectional microphone at a position corresponding to the sound collection method. For example, when it is better to place unidirectional microphones close to each other, adjust the position of the bidirectional microphone so that it does not line up with the unidirectional microphone. It becomes possible to arrange in close proximity without hindering.

  (3) The present invention is characterized in that, in the sound collecting device described above, the unidirectional microphone is rotatably supported on a second axis perpendicular to the rotation axis.

  According to the configuration of the present invention, since the unidirectional microphone can be rotated about two axes, the orientation of the main axis of the unidirectional microphone can be set with various variations, and more various types can be set. Sound can be collected by the sound collection method. In addition, it is possible to finely adjust the orientation of the main axis of the unidirectional microphone in correspondence with various sound collection methods.

  (4) The present invention according to the second means for solving the problem includes two rotation shafts provided so as to be rotatable about two axes around two rotation shafts parallel to each other and a second shaft perpendicular to the rotation shafts. A sound collecting apparatus comprising: a unidirectional microphone; an apparatus main body; and a support unit attached to the apparatus main body and supporting the unidirectional microphone.

  According to the configuration of the present invention, since the two unidirectional microphones are provided so as to be rotatable around two rotation axes that are parallel to each other, the directions of the main axes can be individually changed, and sound collection is possible. It is possible to make the device compatible with various sound collection methods. Here, since the unidirectional microphone is provided in advance, it is possible to easily position the microphone at a position necessary for the sound collection method desired by the user.

  Further, according to the above configuration, since the unidirectional microphone can be rotated on two axes, the orientation of the main axis of the unidirectional microphone can be set in various variations, and a wider variety of accommodation can be achieved. It is possible to collect sound by sound method. In addition, it is possible to finely adjust the orientation of the main axis of the unidirectional microphone in correspondence with various sound collection methods.

  (5) In the sound pickup device according to the present invention, the device main body is a side surface parallel to the rotation axis, and a distance from the rotation axis is a distance equal to or less than ¼ of a wavelength of a sound wave having a specific frequency. This is a sound collecting device.

  According to the configuration of the present invention, when the side surface is arranged on the floor surface, the unidirectionality is at a position where the height from the floor surface is within 1/4 of the wavelength of the specific frequency (frequency of a predetermined audible sound range). Since the rotation axis of the microphone is arranged, it is possible to use the sound collection device as a boundary microphone. Further, since the rotation axis is positioned in parallel with the floor surface, the unidirectional microphone can be rotated on a plane parallel to the floor surface by rotating with the second axis. For this reason, it is possible to perform stereo sound collection with the boundary microphone.

  (6) The present invention according to the third means for solving the problem includes two unidirectional microphones rotatably provided around two rotation axes parallel to each other, and the two rotation axes. A bi-directional microphone in which the straight line and the directivity axis are provided at right angles on a straight line to be connected, and a second support portion that supports the bi-directional microphone so as to be movable in a direction parallel to the rotation axis. It is a sound collection device characterized by this.

  According to the configuration of the present invention, since the two unidirectional microphones are provided so as to be rotatable around two rotation axes that are parallel to each other, the sound collecting device can be changed by individually changing the directions of the main axes. It becomes possible to correspond to various sound collection methods.

  In addition, it is possible to perform various sound collections using a bidirectional microphone and a unidirectional microphone. At the same time, since the position of the bidirectional microphone can be moved in the direction parallel to the rotation axis by the second support portion, when storing the sound collecting device, the bidirectional microphone is replaced with the unidirectional microphone. It is possible to make the sound collecting device compact by arranging them at positions that are aligned with each other. In addition, when collecting sound, it becomes possible to place a bidirectional microphone at a position corresponding to the sound collection method.

  According to the first aspect of the present invention, since the two unidirectional microphones provided so as to be rotatable around two rotation axes parallel to each other are provided, the directivity axis of each microphone is determined by the user. Can be individually arranged at a position corresponding to the sound pickup method. Thereby, sound can be collected by various sound collecting methods.

  In addition, by moving the unidirectional microphones in a predetermined section, it is possible to easily place the two unidirectional microphones in a positional relationship suitable for each sound collection method.

  According to the present invention as set forth in claim 4, since the two unidirectional microphones provided so as to be rotatable around two rotation axes parallel to each other are provided, the directivity axes of the respective microphones are set. It can be individually arranged at a position corresponding to the sound collection method desired by the user. Thereby, sound can be collected by various sound collecting methods. In addition, since the unidirectional microphone can be rotated in two axes, the orientation of the main axis of the unidirectional microphone can be set in various variations, and sound can be collected with a wider variety of sound collection methods. It can be carried out. In addition, it is possible to finely adjust the orientation of the main axis of the unidirectional microphone in correspondence with various sound collection methods.

  According to the sixth aspect of the present invention, since the two unidirectional microphones provided so as to be rotatable around two rotation axes parallel to each other are provided, the directivity axis of each microphone can be determined by the user. Can be individually arranged at a position corresponding to the sound pickup method. Thereby, sound can be collected by various sound collecting methods.

  Further, the position of the bidirectional microphone can be moved by the second support portion in the direction in which the rotation axis extends. For this reason, when housing the sound collecting device, the sound collecting device can be made compact by arranging the bidirectional microphones at positions aligned with the unidirectional microphones. When collecting sound, a bi-directional microphone can be arranged at a position corresponding to the sound collection method.

  A sound collection device according to an embodiment of the present invention will be described in detail with reference to FIGS.

<Outline of Technical Idea of First Embodiment>
The sound collection device according to the present embodiment rotates around two rotation axes that are parallel to each other to thereby change two sound collection directions (directions of the main shaft) and change the direction of the sound collection (hereinafter referred to as “the directional microphone”). And a single bi-directional microphone attached so that the directivity axis faces in a direction orthogonal to a straight line connecting the two rotation axes.

  Here, since the sound collection angles of the unidirectional microphones are provided so as to be individually changeable, variations in how to set the directivities of the two unidirectional microphones can be enriched. The first feature is that a variety of sound pickup methods can be used.

  At the same time, the sound collection device 1 receives from the user an operation for selecting one sound collection mode from a plurality of types of sound collection modes according to the combination of sound collection directions of the unidirectional microphone and / or the bidirectional microphone. It is possible.

  When the sound collection device 1 accepts a selection operation, the sound collection device 1 sets the unidirectional microphone in the sound collection direction corresponding to the selected sound collection mode, switches the bidirectional microphone on / off, and Diverse sound collection is realized by performing audio signal processing corresponding to the selected sound collection mode.

  Here, the positional relationship (distance between microphones) of two unidirectional microphones suitable for each sound collection mode and the positional relationship (distance) between these unidirectional microphones and bi-directional microphones are different. . The second feature of the present embodiment is that the two unidirectional microphones are movable in a predetermined section on a straight line connecting the first axes of these unidirectional microphones. For this reason, by moving a unidirectional microphone in a predetermined section, two unidirectional microphones can be arranged in a positional relationship suitable for each sound collection method with ease of positioning.

  A third feature is that the unidirectional microphone is rotatable about a second axis perpendicular to the rotation axis. Since the unidirectional microphone can rotate about the second axis as well as the first axis in this way, it becomes possible to set the orientation of the main axis of the unidirectional microphone in various variations. Sound can be collected with a wider variety of sound collection methods. In addition, the direction of the main axis of the unidirectional microphone can be finely adjusted in accordance with various sound collection methods.

  A fourth feature is that the bidirectional microphone is supported so as to be movable in a direction parallel to the first axis. As a result, when the sound collecting device is stored, the sound collecting device can be made compact by arranging the bi-directional microphone in a position aligned with the unidirectional microphone. In addition, when collecting sound, it becomes possible to place a bidirectional microphone at a position corresponding to the sound collection method.

<Configuration of sound collection device>
FIG. 1 is a perspective view showing an appearance of a sound collection device 1 according to an embodiment of the present invention. FIG. 2 is a front view of the sound collecting device 1 shown in FIG. In the following description, the front direction of the sound collection device 1 is described as the Y direction, the back direction is described as the -Y direction, the right side is described as the -X direction, and the left side is described as the X direction. The sound collection device 1 includes a device main body 1B having an internal configuration which will be described later with reference to FIG. 4 in a long, substantially rectangular parallelepiped housing 1A.

  Two unidirectional microphones 2 (first unidirectional microphones of the present invention) are arranged side by side in the ± X direction on the upper surface of the apparatus main body 1B, and the rotation axis a (shown above by the one-dot chain line in FIG. 1). 1 axis, corresponding to the rotation axis of the present invention), and supported by the support portion 21 so as to be able to rotate 360 degrees in the direction (left-right direction) indicated by the arrows AA in FIG.

  1 is supported so as to be rotatable by 180 degrees in a direction (height direction) indicated by an arrow BB in the same figure around a rotation axis b (corresponding to the second axis of the present invention) indicated by a one-dot chain line in FIG. It is pivotally supported by the part 21. As a result, the user can manually change the sound collection angle of the unidirectional microphone 2 and can pick up sound in various directions. This makes it possible to realize a variety of sound collection. Furthermore, since the unidirectional microphones 2A and 2B are supported so as to be rotatable about two axes, it is possible to set the sound collection angle at a wider variety of angles as compared with the configuration capable of rotating only with one axis. It becomes possible. This also makes it possible to realize a wider variety of sound collection.

  The configuration of the support portion 21 will be described later in detail with reference to FIG. Hereinafter, the unidirectional microphone 2 disposed on the −X side is referred to as a unidirectional microphone 2A, and the unidirectional microphone 2 disposed on the X side is referred to as a unidirectional microphone 2B.

  Further, between each unidirectional microphone 2, the unidirectional microphones 2 are arranged in a straight line (in parallel to the X axis), and the sound collection direction (front side and back side) is the straight line. The bi-directional microphone 3 is provided so as to be in the ± Y directions orthogonal to each other.

  Thereby, the sound in the direction orthogonal to the straight line can be collected by the bidirectional microphone 3. The bidirectional microphone 3 is configured by attaching two unidirectional microphones 31 and 32 back to back. The microphone arranged on the Y side is the unidirectional microphone 31, and the microphone arranged on the −Y side is the unidirectional microphone 32. The unidirectional microphones 31 and 32 are preferably realized with, for example, those having the same sound collection characteristics as the unidirectional microphone 2 from the viewpoint of realizing various sound collection modes described later.

  As described above, by turning on only one of the unidirectional microphones 31 and 32, the bidirectional microphone 3 can pick up only one of the Y direction and the -Y direction. It has become.

  The bi-directional microphone 3 is attached to the apparatus main body 1B via the support portion 3A, and the bi-directional microphone 3 is moved by moving the support portion 3A in the direction in which the rotation axis a extends (the direction of the arrow c). It can move in this direction. The bi-directional microphone 3 is positioned at the same height as the unidirectional microphone 2 in the state where the support portion 3A is the lowest. For this reason, it is possible to make the sound collection device 1 compact, and it is suitable for storage. Further, at the position where the support portion 3A is the highest, the bidirectional microphone 3 is located at a position higher than the height of the unidirectional microphones 2A and 2B.

  A slit 11 is formed on the upper surface of the housing 1A on a straight line connecting the two unidirectional microphones 2 to each other. The slits 11 are formed at two locations from the X-side end of the upper surface to the vicinity of the bidirectional microphone 3 and from the −X-side end to the vicinity of the bidirectional microphone 3. A support portion 21B is loosely inserted into the slit 11 (11B) formed on the X side, and the support portion 21 is guided by the slit 11B so as to be movable between both end portions of the slit 11B (FIG. 1, FIG. (See dotted arrow in FIG. 2). A support portion 21A is loosely inserted into the slit 11 (11A) formed on the −X side, and the support portion 21 is guided by the slit 11A so as to be movable between both end portions of the slit 11A (FIG. 1). , See dotted arrow in FIG. 2).

  In the state where the height of the bidirectional microphone 3 is the highest, the height is higher than that of the unidirectional microphone 2. For this reason, the two unidirectional microphones 2 are placed close to each other by sliding the two unidirectional microphones 2 toward the bidirectional microphone 3 and entering the lower part of the bidirectional microphone 3. It is possible.

  As described above, the positional relationship between the two unidirectional microphones 2 suitable for various sound collection modes and the positional relationship between the bidirectional microphone 3 and the unidirectional microphone 2A are different. In the present embodiment, the two unidirectional microphones 2A are slid in the XX direction by the slit 11 and the support portion 21, thereby easily positioning the two unidirectional microphones 2A, The positional relationship between the directional microphone 2A and the bidirectional microphone 3 can be adjusted to a positional relationship suitable for various sound collection modes.

  On the Y side surface of the sound collecting device 1, an operation unit 4 is provided on the -X side, a display unit 4A is provided on the center portion, and an external interface 5 is provided on the X side. The operation unit 4 includes one operation button 41 and four operation buttons 42 (42A to 42D) arranged on the top, bottom, left, and right of the operation button 41, and the user presses the operation button 41 or the operation button 42 with a finger or the like. Thus, various operations are accepted. This operation includes, for example, the above-described selection operation (mode selection operation) of the sound collection mode.

  A specific example of the mode selection operation will be described. Any one of the sound collection modes is displayed on the display unit 4A. The operation button 42A is arranged above, and the operation button 42A is arranged below. Each time the operated button 42B is pressed, the displayed sound collection mode is switched.

  Here, when the operation button 41 is pressed, the displayed sound collection mode is selected. As a result, the microphones 2A and 2B are set in the sound collection direction according to the selected sound collection mode, the on / off of the bidirectional microphone 3 is switched, and the sound signal processing setting according to the sound collection mode is set. Switching takes place.

  The details of the plurality of types of sound collection modes and the sound signal processing when each sound collection mode is selected will be described in detail later.

  The display unit 4A is configured by, for example, an LCD (Liquid Crystal Display) or the like. The operation unit 4 and the display unit 4A may be integrally provided by providing a touch panel on the surface of the display unit 4A.

  The external interface 5 includes a plurality of connection terminals for connecting to an external audio device (for example, a headphone device, an audio recorder, etc.), thereby enabling the collected audio signal to be output to the external audio device. ing. The sound collecting device 1 is supplied with electric power from a power outlet (not shown) via the power cord 1C.

  In the present embodiment, the sound collection device 1 can be used as a boundary microphone by installing the back surface on the floor surface. Here, in order to use the sound collection device 1 as a boundary microphone, the dimension D from the rear surface to the rotation axis a of the unidirectional microphone 2 is a specific frequency (a predetermined frequency in the audible sound range, for example, 10 kHz, 5 kHz). Is preferably smaller than ¼ wavelength. The reason for this is to prevent the cancellation of the sound to be collected by the reflected sound from the floor surface. When the dimension D is a value smaller than a quarter wavelength of 5 kHz (less than 17 mm), the influence of the reflected sound is small and sound can be collected with sufficient sound quality. However, the dimension D is preferably 1/1/10 kHz. The value is smaller than 4 wavelengths (less than 8.5 mm).

  In addition, it is good also as a structure which can use the sound collection device 1 as a boundary microphone by installing the front surface of the sound collection device 1 on a floor surface. In this case, the apparatus main body 1B is configured such that the dimension from the front to the rotation axis a of the unidirectional microphone 2 is smaller than a quarter wavelength of the specific frequency.

  FIG. 3A is a diagram showing attachment of the support portion 21 and the unidirectional microphone 2. FIG. 2B is a side cross-sectional view showing the configuration of the unidirectional microphone 2, the support portion 21, and their peripheral portions shown in FIG. 1. Moreover, the figure (c) is ee sectional drawing of the unidirectional microphone 2 shown in (b).

  As shown in FIG. 2A, the support portion 21 has a shape in which a rectangular parallelepiped 21b is formed on the upper portion of a cylinder 21a having a side cross section of H shape. The unidirectional microphone 2 has a notch 2 ′ formed at the end, and the shaft 22 is inserted from the Y-Y direction with the upper end of the rectangular parallelepiped 21b inserted in the notch 2 ′. Has been. The unidirectional microphone 2 is rotated in the BB direction using the shaft 22 as a rotation axis b.

  In addition, the concave portion of the cylinder 21 a is fitted in the slit 11, and the support portion 21 is movable along the slit 11 by being guided by the slit 11 by sandwiching the periphery of the slit 11 in the housing 1 </ b> A with the convex portion. A unidirectional microphone 2 is attached to the apparatus main body 1B. As a result, the unidirectional microphone 2 can be slid in the XX direction. Further, the unidirectional microphone 2 can be rotated in the AA direction with the circular center of the cylinder 21a as the rotation axis a.

  FIG. 4 is a block diagram showing the configuration of the sound collection device 1 shown in FIG. In addition to the unidirectional microphone 2, the bidirectional microphone 3, the operation unit 4, the display unit 4 </ b> A, the external interface 5, and the like, the sound collection device 1 includes an A / D (analog / digital) converter 6, a storage unit 7, a control unit 8, a signal processing unit 9, and a D / A (digital / analog) converter 10.

  The A / D converter 6 is connected to each unidirectional microphone 2 and the bidirectional microphone 3 via signal lines (not shown), and the unidirectional microphone 2 and the bidirectional microphone 3 (single The 4-channel analog audio signal input from the directional microphones 31, 32) is converted into a digital audio signal and input to the signal processing unit 9.

  The storage unit 7 is realized by, for example, a nonvolatile semiconductor memory or a hard disk, and stores various programs for executing various audio signal processes corresponding to various sound collection modes. Various programs include MS stereo (0 ° orientation) program, MS stereo (-90 ° orientation) program, MS surround (0 ° orientation) program, MS surround (-90 ° orientation) program, sound pressure secondary gradient type narrow Orientation program, delay addition type narrow orientation program, MS stereo zoom (sound pressure secondary gradient type) program, MS stereo zoom (delay addition type) program, monaural opposed directional axis rotation program, pair microphone stereo (with level difference and phase difference) There are a program, a pair microphone stereo (XY level difference) program, an addition type monaural narrow directivity program, and the like.

  The MS stereo (0 ° orientation) program is a program read by the control unit 8 when the MS stereo (0 ° orientation) mode is selected. The MS stereo (-90 ° direction) program is a program read by the control unit 8 when the MS stereo (-90 ° direction) mode is selected. The MS surround (0 ° orientation) program is a program read by the control unit 8 when the MS surround (0 ° orientation) mode is selected.

  The MS surround (-90 ° direction) program is a program read by the control unit 8 when the MS surround (−90 ° direction) mode is selected. The sound pressure secondary gradient type narrow directivity program is a program read by the control unit 8 when the sound pressure secondary gradient type narrow directivity mode is selected. The delay addition type narrow pointing program is a program read by the control unit 8 when the delay addition type narrow pointing mode is selected.

  The MS stereo zoom (sound pressure secondary gradient type) program is a program read by the control unit 8 when the MS stereo zoom (sound pressure secondary gradient type) mode is selected. The MS stereo zoom (delay addition type) program is a program read by the control unit 8 when the MS stereo zoom (delay addition type) mode is selected. The monaural opposed directional axis rotation program is a program read by the control unit 8 when the monaural opposed directional axis rotation mode is selected.

  The pair microphone stereo (combined level difference / phase difference) program is a program read by the control unit 8 when the pair microphone stereo (combined level difference / phase difference) mode is selected. The pair microphone stereo (XY level difference) program is a program read by the control unit 8 when the pair microphone stereo (XY level difference) mode is selected. The addition type monaural narrow pointing program is a program read by the control unit 8 when the addition type monaural narrow pointing mode is selected.

  Details of the various sound collection modes will be described later with reference to FIGS.

  The control unit 8 receives an operation signal indicating a mode selection operation from the operation unit 4. The control unit 8 performs display control on the display unit 4A. For example, as described above, every time an operation signal indicating that the operation buttons 42A and 42B are pressed is input from the operation unit 4, the sound collection mode to be sequentially displayed is switched. .

  Moreover, the control part 8 acquires the selected sound collection mode by the input of the operation signal which shows the said mode selection operation. When the sound collection mode is acquired, the control unit 8 executes a mode setting process. In the mode setting process, the control unit 8 reads a program corresponding to the mode selection operation acquired as described above from the storage unit 7 and executes a process of setting the read program in the signal processing unit 9. Thereby, the signal processing unit 9 can execute the sound signal processing according to the sound collection mode, that is, the sound signal processing according to the combination of the sound collection angles of the unidirectional microphones 2 and / or the bidirectional microphones 3. It becomes possible, and it becomes possible to realize various sound collections. The mode setting process will be described later in detail with reference to FIG.

  The signal processing unit 9 is realized by a DSP or the like, for example, and performs audio signal processing on each audio signal input from each unidirectional microphone 2 and / or the bidirectional microphone 3 via the A / D converter 6. . The signal processing unit 9 changes the setting of the audio signal processing by the control unit 8, and performs different audio signal processing according to the setting. Details of the audio signal processing corresponding to the various modes will be described later with reference to FIGS. The signal processing unit 9 inputs the audio signal after the audio signal processing to the external interface 5 via the D / A converter 10. This makes it possible to input the collected audio signal to an external audio device. In FIG. 4, the D / A converted analog signal is input to the external interface 5, but there may be a path for inputting the digital signal to the external interface 5 as it is.

<Description of various sound collection modes>
Hereinafter, the arrangement of the unidirectional microphones 2A and 2B, the direction of the directional axis, and the audio signal processing in each sound collection mode will be described. In this specification, as shown in FIG. 1, the −Y direction is described as 0 °, the Y direction as 180 °, the −X direction as 90 °, and the X direction as −90 °. . In the explanation of some sound collection modes, the X direction is described as a 270 ° direction in order to clearly indicate the range of angles. “−90 °” indicates that it is rotated 90 ° counterclockwise (minus direction) from the 0 ° axis, but equivalent to this, it is rotated 270 ° clockwise (plus direction). Show.

《MS stereo (0 ° orientation) mode》
In the MS stereo (0 ° direction) mode, the audio signal from the unidirectional microphone 32 is a Mid signal, the audio signals from the unidirectional microphones 2A and 2B are Side signals, and the -Y direction (0 ° direction) This is a mode for performing stereo sound collection in the MS stereo system with the front side as the front.

<< MS stereo (0 ° orientation) mode: setting of each microphone 2A, 2B, 31, 32 >>
FIG. 5A is a top view of the sound collection device 1 in which the unidirectional microphone 2 is set in the MS stereo (0 ° direction) mode, and FIG. 5B is a front view.

  In the MS stereo (0 ° orientation) mode, the microphone angle of the unidirectional microphone 2B is set to 90 °, and the microphone angle of the unidirectional microphone 2A is set to −90 °.

  In the MS stereo system, in order to achieve uniform sound collection, it is preferable that the center of the diaphragm for the Side signal microphone and the center of the diaphragm for the Mid signal microphone are arranged in the same manner. That is, in this mode, the center of the diaphragms of the unidirectional microphones 2A and 2B and the bidirectional microphone 3 are arranged in the same manner in order to achieve uniform sound collection in the XX direction and the -Y direction. Ideally. For this reason, in the MS stereo (0 ° direction) mode, the present bidirectional microphone 3 is set to the highest. At the same time, the unidirectional microphones 2 </ b> A and 2 </ b> B are arranged closest to the bidirectional microphone 3 so that the bidirectional microphones 3 enter under the bidirectional microphone 3. Thereby, the bi-directional microphone 3 and the unidirectional microphones 2A and 2B can be arranged in an ideal positional relationship.

  Then, only the unidirectional microphone 32 is turned on and the unidirectional microphone 31 is turned off. This ON indicates that the audio signal input to the signal processing unit 9 is used for audio signal processing, and OFF indicates that it is not used for audio signal processing.

<< MS stereo (0 ° orientation) mode: Audio signal processing >>
FIG. 6A is a diagram for explaining an audio signal in the MS stereo (0 ° orientation) mode, and FIG. 6B shows the function of the signal processing unit 9 in the MS stereo (0 ° orientation) mode. FIG. 6A, FIG. 7A, FIG. 8A, FIG. 9A, FIG. 13, FIG. 17A, B, FIG. 19A, and FIG. The directional characteristics of the unidirectional microphone 2 and the bi-directional microphone 3 are indicated by alternate long and short dash lines. Further, the directivity characteristics of the synthesized signal after the sound signal processing is performed on the sound from the unidirectional microphone 2 and the bidirectional microphone 3 are indicated by a thick solid line.

  In the MS stereo (0 ° direction) mode, the signal processing unit 9 includes a gain adjustment unit 91, multiplication units 92A and 92B, and addition units 93A, 93B, and 93C.

  The signal processing unit 9 inputs the audio signal from the unidirectional microphone 32 to the adding units 93A and 93B as a Mid signal. In addition, the signal processing unit 9 inputs the audio signal from the unidirectional microphone 2A to the multiplication unit 92A. The multiplier 92A multiplies the audio signal from the input microphone 2A by −1 and inputs the result to the adder 93C. In addition, the signal processing unit 9 inputs the audio signal from the unidirectional microphone 2B to the adding unit 93C. The adder 93 </ b> C adds the input audio signal × −1 from the microphone 2 </ b> A and the audio signal from the microphone 2 </ b> B to generate a Side signal, and inputs the Side signal to the gain adjuster 91. The gain adjusting unit 91 adjusts the level of the input Side signal to adjust the level balance with the Mid signal, and inputs the level to the adding unit 93A and the multiplying unit 92B.

  The adder 93 </ b> A adds the input Mid signal and Side signal to generate an R channel audio signal, and inputs the R channel audio signal to the D / A converter 10.

  The multiplier 92B multiplies the input Side signal by −1 and inputs the result to the adder 93B.

  The adder 93 </ b> B adds the input Mid signal and the Side signal × −1 to generate an L-channel audio signal and inputs it to the D / A converter 10.

  As described above, in the MS stereo (0 ° orientation) mode, sound can be collected by the MS stereo system with 0 ° as the front (directing axis).

  In addition to the MS stereo (0 ° orientation) mode, the MS stereo (180 ° orientation) mode may be included in various sound collection modes. In this case, instead of the unidirectional microphone 32, the unidirectional microphone 31 is turned on, and the audio signal from the unidirectional microphone 31 is set as a Mid signal in the same manner as in the MS stereo (0 ° direction) mode. Audio signal processing is performed. In this case, sound can be collected by the MS stereo method with the 180 ° direction as the front.

<MS stereo (-90 ° orientation) mode>
The MS stereo (−90 ° direction) mode is an MS stereo system in which the audio signal from the unidirectional microphone 2A is a Mid signal, the audio signal from the bidirectional microphone 3 is a Side signal, and the −90 ° direction is the front. This is a mode for collecting stereo sound in

<< MS stereo (-90 ° orientation) mode: setting of each microphone 2A, 2B, 31, 32 >>
Similar to the MS stereo (0 ° orientation) mode, the microphone angle of the unidirectional microphone 2A is set to be −90 °. In this mode, since the unidirectional microphone 2B is not used, the microphone angle of the unidirectional microphone 2B may be set in any manner.

  As described above, in the MS stereo system, in order to achieve uniform sound collection, the center of the diaphragm for the Side signal microphone and the center of the diaphragm for the Mid signal microphone are arranged coaxially. It is preferable. That is, in this mode, it is ideal that the center of the diaphragm of the bidirectional microphone 3 and the center of the diaphragm of the unidirectional microphone 2A are arranged in the same manner. For this reason, in the MS stereo (-90 ° direction) mode, the present bidirectional microphone 3 is set to the highest.

  At the same time, the unidirectional microphone 2A is arranged closest to the bidirectional microphone 3 so that the unidirectional microphone 2A enters below the bidirectional microphone 3. Thereby, the bi-directional microphone 3 and the unidirectional microphone 2A can be arranged in an ideal positional relationship.

<< MS stereo (-90 ° orientation) mode: Audio signal processing >>
FIG. 7A is a diagram for explaining audio signal processing in the MS stereo (-90 ° direction) mode. FIG. 7B is a block diagram illustrating a functional configuration of the signal processing unit 9 in the MS stereo (−90 ° direction) mode.

  The signal processing unit 9 includes a gain adjustment unit 91-1, multiplication units 92-1A and 92-1B, and addition units 93-1A, 93-1B, and 93-1C. The signal processing unit 9 inputs the audio signal from the unidirectional microphone 2A as a Mid signal to the adding unit 93-1A and the adding unit 93-1B. On the other hand, the signal processing unit 9 inputs the audio signal from the bidirectional microphone 3 as a Side signal to the gain adjustment unit 91-1.

  Here, in order for the unidirectional microphones 31 and 32 to function as the bidirectional microphone 3, the signal processing unit 9 inputs the output of the microphone 32 to the adding unit 93-1 </ b> C and outputs the output of the microphone 31. It inputs into the multiplication part 92-1A. The multiplier 92-1A multiplies the input signal of the microphone 31 by -1, and inputs the result to the adder 93-1C. The adder 93-1C adds the output signal of the microphone 32 and the input output of the microphone 31 × −1 signal, and outputs the result as a Side signal.

  The gain adjusting unit 91-1 adjusts the level of the Side signal in order to balance the level with the Mid signal, and inputs the adjusted Side signal to the adding unit 93-1A and the multiplying unit 92-1. The multiplier 92-1 multiplies the input Side signal by −1 and inputs the result to the adder 93-1B.

  The adder 93-1A adds the input Mid signal and Side signal, and inputs the added audio signal to the D / A converter 10 as an R channel audio signal. The adder 93-1B adds the input Mid signal and the input Side signal × −1 to generate an L channel audio signal.

  By collecting sound in the MS stereo (-90 ° direction) mode, stereo sound with the X direction in front can be obtained.

  In addition to the MS stereo (-90 ° orientation) mode, the MS stereo (90 ° orientation) mode can be included in various sound collection modes. In this case, the microphone angle of the unidirectional microphone 2B is set to 90 °, and the unidirectional microphone 2B is disposed at the nearest position of the bidirectional microphone 3. And the said audio | voice signal processing is performed using the audio | voice signal from the unidirectional microphone 2B as a Mid signal. In this mode, stereo sound can be collected with the -X direction as the front.

《MS surround (0 °) mode》
In the MS surround (0 ° direction) mode, the front is set to 0 ° (directing axis), and the sound from the unidirectional microphone 2 and the bi-directional microphone 3 is used to perform 4-channel surround sound collection using the MS method. Mode.

<< MS surround (0 ° orientation) mode: setting of each microphone 2A, 2B, 31, 32 >>
The unidirectional microphones 2A and 2B and the bidirectional microphone 3 are set as in the MS stereo (0 ° direction) mode (see FIG. 5). Here, as described above, the center of the diaphragm for the Side signal microphone and the center of the diaphragm for the Mid signal microphone are preferably arranged in the same manner. For this reason, even in the MS surround (0 ° direction) mode, the present bi-directional microphone 3 is set in the most extended state. At the same time, the unidirectional microphones 2 </ b> A and 2 </ b> B are arranged closest to the bidirectional microphone 3 so that the bidirectional microphones 3 enter under the bidirectional microphone 3. In the MS surround (0 ° direction) mode, both unidirectional microphones 31 and 32 are turned on.

<< MS Surround (0 °) mode: Audio signal processing >>
FIG. 8A is a diagram for explaining audio signal processing in the MS surround (0 ° direction) mode. FIG. 8B is a block diagram showing a functional configuration of the signal processing unit 9 in the MS surround (0 ° direction) mode.

  In the MS surround (0 ° direction) mode, the signal processing unit 9 includes addition units 93D and 93E in addition to the gain adjustment unit 91, multiplication units 92A and 92B, and addition units 93A, 93B, and 93C.

  The signal processing unit 9 generates an R channel audio signal and an L channel audio signal in the same manner as in the MS stereo (0 ° direction) mode. The front R channel is referred to as an FR channel, and the front L channel is referred to as an FL channel.

  Further, the signal processing unit 9 inputs the Side signal output from the gain adjustment unit 91 to the addition unit 93D and inputs the output signal (Rmid signal) of the unidirectional microphone 31 to the addition unit 93D. The adder 93D adds these input signals (Side signal and the output signal of the unidirectional microphone 31) to generate a rear-side R channel (RR channel) audio signal, and D / A Input to the converter 10.

  Further, the signal processing unit 9 inputs the Side signal × −1 output from the multiplication unit 92B to the addition unit 93E, and inputs the output signal (Rmid signal) of the unidirectional microphone 31 to the addition unit 93E. The adder 93E adds these input signals (Side signal × -1 and the output signal of the unidirectional microphone 31) to generate a rear side L channel (RL channel) audio signal, Input to the D / A converter 10.

  As described above, in the MS surround (0 ° direction) mode, 4 channels of surround sound can be collected by the MS method with the front face set to 0 °.

  In addition to the MS surround (0 ° orientation) mode, an MS surround (180 ° orientation) mode can be included in various sound collection modes. In this case, the audio signal from the unidirectional microphone 32 is used as the RMid signal, and the audio signal from the unidirectional microphone 31 is used as the FMid signal in the same manner as the MS surround (0 ° direction) mode. Processing is performed. In this case, four channels of sound can be collected by the MS method with the 180 ° direction as the front.

《MS surround (-90 ° orientation) mode》
The MS surround (-90 ° direction) mode is a mode in which 4-channel surround sound collection is performed using sound from the unidirectional microphone 2 and the bidirectional microphone 3 with the front (directing axis) being −90 °. It is.

<< MS surround (-90 ° direction) mode: setting of each microphone 2A, 2B, 31, 32 >>
In the MS surround (-90 ° direction) mode, the unidirectional microphones 2A and 2B and the bi-directional microphone are set as in the MS stereo (−90 ° direction) mode. Here, the unidirectional microphones 2A and 2B and the bidirectional microphone 3 are set as in the MS stereo (0 ° direction) mode (see FIG. 5). Here, as described above, the center of the diaphragm for the Side signal microphone and the center of the diaphragm for the Mid signal microphone are preferably arranged in the same manner. For this reason, the bi-directional microphone 3 is set to the highest level even in the MS surround (-90 ° direction) mode. At the same time, the unidirectional microphones 2 </ b> A and 2 </ b> B are arranged closest to the bidirectional microphone 3 so that the bidirectional microphones 3 enter under the bidirectional microphone 3. In the MS surround (-90 ° direction) mode, both unidirectional microphones 31 and 32 are turned on.

<< MS Surround (-90 ° orientation) mode: Audio signal processing >>
FIG. 9A is a diagram for explaining audio signal processing in the MS surround (-90 ° direction) mode. FIG. 9B is a block diagram showing a functional configuration of the signal processing unit 9 in the MS surround (-90 ° direction) mode.

  In the MS surround (-90 ° direction) mode, the signal processing unit 9 includes gain adjustment units 91-2A and 91-2B, multiplication units 92-2A, 92-2B, and 92-2C, and addition units 93-2A to 93-2A. 93-2E.

  The signal processing unit 9 converts the audio signal from the unidirectional microphone 2A into a front-side Mid signal (FMid signal) and inputs it to the adder 93-2A and the adder 93-2B. Further, the signal processing unit 9 inputs the audio signal from the bidirectional microphone 3 as a Side signal to the gain adjusting unit 91-2A. Here, in order to make the unidirectional microphones 31 and 32 function as a bidirectional microphone, the signal processing unit 9 inputs the output of the microphone 32 to the adding unit 93-2E and multiplies the output of the microphone 31. Input to 92-2C. The multiplier 92-2C multiplies the input signal of the microphone 31 by -1, and inputs the result to the adder 93-2E. The adder 93-2E generates the Side signal by adding the input output signal of the microphone 32 and the input output of the microphone 31 × −1 signal, and inputs the Side signal to the gain adjusting units 91-2A and 91-2B. .

  The gain adjusting unit 91-2A adjusts the level of the Side signal and inputs the level to the adding unit 93-2A and the multiplying unit 92-2A in order to balance the level with the FMid signal. Multiplier 92-2A multiplies the input Side signal by -1 and inputs the result to adder 93-2B.

  The adder 93-2A generates an audio signal of the front-side R channel (FR channel) by executing audio signal processing for adding the input FMid signal and the Side signal. The audio signal of the FR channel is input to the D / A converter 10. Also, the adder 93-2B generates a front side L channel (FL channel) audio signal by executing audio signal processing that adds the input FMid signal and the input Side signal × −1. The FL channel audio signal is input to the D / A converter 10.

  The signal processing unit 9 converts the audio signal from the unidirectional microphone 2B into a rear-side Mid signal (RMid signal) and inputs it to the adding unit 93-2C and the adding unit 93-2D. The signal processing unit 9 branches the Side signal input to the gain adjustment unit 91-2A and inputs the branched Side signal to the gain adjustment unit 91-2B. The gain adjusting unit 91-2B adjusts the level of the input Side signal and inputs it to the multiplying unit 92-2B and the adding unit 93-2D in order to balance the level with the RMid signal. The multiplier 92-2B multiplies the input Side signal by −1 and inputs the result to the adder 93-2C.

  The adder 93-2D generates an audio signal of the rear R channel (RR channel) by executing audio signal processing that adds the input RMid signal and the input Side signal. The audio signal of the RR channel is input to the D / A converter 10. Further, the adder 93-2C generates a sound signal of the rear side L channel (RL channel) by executing sound signal processing of adding the input RMid signal and the Side signal × −1. The audio signal of the RL channel is input to the D / A converter 10.

  By collecting sound in the MS surround mode, it is possible to perform surround sound collection of four channels of the FR channel, FL channel, RR channel, and RL channel.

  In addition to the MS surround (-90 ° direction) mode, an MS surround (90 ° direction) mode can be included in various sound collection modes. In this case, the sound signal from the unidirectional microphone 2A is used as the RMid signal, and the sound signal from the unidirectional microphone 2B is used as the FMid signal, which is the same sound as in the MS surround (-90 ° direction) mode. Signal processing is performed. In this case, four channels of sound can be collected by the MS method with the 90 ° direction as the front.

《Sound pressure secondary gradient type narrow pointing mode》
The sound pressure secondary gradient type narrow directivity mode has narrow directivity in the X direction or -X direction by adding one of the sound signals from the unidirectional microphones 2A and 2B in reverse phase. This is a mode for collecting sound.

<< Sound pressure secondary gradient type narrow directivity mode: setting of each microphone 2A, 2B, 31, 32 >>
FIG. 10A is a top view of the sound collection device 1 in which the unidirectional microphone 2 is set in the sound pressure secondary gradient type narrow directivity mode, and FIG. 10B is a front view.

  In the sound pressure secondary gradient type narrow directivity mode, in order to provide narrow directivity in the X direction, the microphone angles of the unidirectional microphones 2A and 2B are set to −90 °. Further, in order to provide narrow directivity in the −X direction, the microphone angles of the unidirectional microphones 2A and 2B are set to 90 °. In addition, both unidirectional microphones 31 and 32 are turned off.

  Further, the distance d1 between the unidirectional microphones 2A and 2B is adjusted. Here, the frequency characteristic changes depending on the distance d1.

  FIG. 11 is a graph showing frequency characteristics in the sound pressure secondary gradient type narrow directivity mode, where (a) is a graph when the distance d1 / 2 is 0.034 m, and (b) is the distance d1 / 2. Is a graph in the case of 0.068 m.

  In this graph and the graph of FIG. 12, the horizontal axis indicates frequency (Hz) and the vertical axis indicates level (dB). In addition, x1 indicates the frequency characteristic of sound input to the unidirectional microphones 2A and 2B at 0 °, x2 indicates the frequency characteristic of sound input at 30 °, and x3 is input at 60 °. The frequency characteristics of are shown.

  As shown in FIGS. 11A and 11B, the frequency at which the dip occurs increases as the distance d1 increases. Since the dip occurs in the high range, the level of the low range is higher than the high range as the distance d1 increases. Further, as shown in FIG. 11 (a), the distance d1 indicates that the dip generated in the lowest frequency in FIG. 11 (b) is generated in the lower frequency than the dip generated in the lowest frequency. The more you open, the lower the dip. For this reason, the sound quality deteriorates as the distance d1 increases.

  From the above, it is preferable that the distance d1 is set to be narrower as the high sound is the sound collection target, and the distance d1 is set to be wide as long as the poor sound quality is acceptable when the low frequency is the sound collection target. Thus, the distance d1 is adjusted according to the sound range of the sound to be collected.

<< Sound pressure secondary gradient type narrow directivity mode: Audio signal processing >>
FIG. 13 is a diagram for explaining audio signal processing in the sound pressure secondary gradient type narrow directivity mode. FIG. 14A is a block diagram showing a functional configuration of the signal processing unit 9 in the sound pressure secondary gradient type narrow directivity mode shown in FIG.

  The signal processing unit 9 includes a multiplication unit 92-3 and an addition unit 93-3. The signal processing unit 9 inputs the audio signal s1 from the unidirectional microphone 2 in the directional direction (the unidirectional microphone 2B in FIG. 9B) to the adding unit 93-3. At the same time, the audio signal s2 from the unidirectional microphone 2 (unidirectional microphone 2A in FIG. 9B) on the opposite side of the directional direction is input to the multiplier 92-3. The multiplier 92-3 multiplies the input audio signal s2 by -1 (in reverse phase) and inputs the result to the adder 93-3.

  The adder 93-3 performs audio signal processing for adding and synthesizing the input audio signal s1 and the input audio signal s2 × -1. The audio signal after the addition synthesis is input to the D / A converter 10.

  Here, since the sound from the front of the unidirectional microphone 2B is input to the unidirectional microphone 2A and the unidirectional microphone 2B with a predetermined time difference, the phase is different, but the sound from the side is almost the same. Since the signals are input at the same timing, the phases are almost the same. For this reason, by the above audio signal processing, the audio signal s2 is reversed in phase and added and synthesized with the audio signal s1, so that the audio phase from the front side is a predetermined frequency f1 whose audio frequency is determined by two microphone intervals D. At frequencies below (f1 = Vc / (2D), where Vc is the sound velocity), the phase of the sound from the side is reversed, and only the sound from the side is canceled. Thereby, sound collection with narrow directivity toward the front side (X side or -X side) can be performed.

  Since the sound of the low sound range has a longer wavelength than the sound of the high sound range, the level is also lowered by the sound signal processing. Therefore, the sound pressure secondary gradient type narrow directivity mode is suitable for narrow directivity sound collection in an environment with a lot of low-frequency noise.

《Delay addition type narrow pointing mode》
In the delay addition type narrow directivity mode, the sound signal s1 is delayed by time t1 and added to the sound signal s2, thereby collecting sound having narrow directivity in the X direction or the -X direction.

  The time t1 is the time until the sound from the same sound source located in front of the unidirectional microphone 2B is input to the unidirectional microphone 2A and the time until the sound is input to the unidirectional microphone 2B. It is a time difference.

<< Delay addition type narrow directivity mode: setting of each microphone 2A, 2B, 31, 32 >>
Even in the delay addition type narrow directivity mode, the microphone angles of the unidirectional microphones 2A and 2B are set in the same manner as in the sound pressure secondary gradient type narrow directivity mode. In addition, both unidirectional microphones 31 and 32 are turned off.

  In the delay addition type narrow directivity mode, the degree of narrow directivity changes depending on the distance d1 between the unidirectional microphones 31 and 32.

  12A and 12B are graphs showing frequency characteristics in the delay addition type narrow directivity mode. FIG. 12A is a graph in the case where the distance d1 / 2 is 0.034 m, and FIG. It is a graph in case of 068m.

  In the delay addition type narrow directivity mode, the audio signal s1 is delayed by the time t1 and added to the audio signal s2. However, in this process, the phase of the audio from 0 ° coincides in all frequency bands, so that a dip occurs. The sound is picked up without changing the frequency characteristics. On the other hand, as shown in FIGS. 12 (a) and 12 (b), the sound at 60 ° has more dip in the side direction, as shown by the fact that the sound at 60 ° has more dip. For this reason, the sound level in the side direction is lowered, and thereby, the sound is collected specifically for the sound in the front direction.

  Here, as shown in FIGS. 12 (a) and 12 (b), as the distance d1 increases, more dip occurs in the sound in the side direction, and the dip occurs in a lower frequency range. For this reason, as the distance d1 increases, the sound level in the side direction decreases, and the degree of narrow directivity increases. In addition, as the distance d1 increases, the sound quality deteriorates due to the side direction audio dip. For this reason, when the degree of narrow directivity is set high, the distance d1 can be set wide as long as the deterioration of sound quality is acceptable.

  As described above, in the delay addition type narrow directivity mode, the narrow directivity degree can be adjusted by adjusting the distance d1.

<< Narrow directivity mode with delay addition: Audio signal processing >>
The audio signal processing in the delay addition type narrow directivity mode will be described with reference to FIGS. 13 and 14B. FIG. 13 is a diagram for explaining not only the sound pressure secondary gradient type narrow pointing mode sound signal processing but also the delay addition type narrow pointing mode sound signal processing. FIG. 14B is a block diagram showing a functional configuration of the signal processing unit 9 in the delay addition type narrow directivity mode shown in FIG.

  The signal processing unit 9 includes an adding unit 93-4 and a delay unit 94-4. The signal processing unit 9 inputs the audio signal s2 from the unidirectional microphone 2 (here, the unidirectional microphone 2A) on the opposite side of the directivity direction to the adder 93-4. At the same time, the audio signal s1 from the unidirectional microphone 2 in the directional direction (here, the unidirectional microphone 2B) is input to the delay unit 94-4. The delay unit 94-4 delays the input audio signal s1 by time t1. The signal processing unit 9 inputs the delayed audio signal s1 to the adding unit 93-4.

  The adder 93-4 adds the audio signal s 2 and the delayed audio signal s 1 and inputs them to the D / A converter 10.

  Here, as described above, the sound from the side is input to the unidirectional microphones 2A and 2B with almost no time difference, but the sound from the front of the unidirectional microphone 2B is simply the time difference of time t1. The signals are input to the unidirectional microphones 2A and 2B, respectively. Therefore, by delaying by the time t1, the phase of the audio signal s1 and the audio signal s2 coincide with each other for the audio component from the front side, but both audio signals s1 and s2 have the audio component from the side side. Out of phase. For this reason, by adding the audio signal s1 and the audio signal s2, the signal level of the audio component from the front side is amplified, but the level of the audio component from the side is not amplified as compared with the audio component from the front side. .

  As a result, the sound component from the front side becomes relatively large, and in the delay addition type narrow pointing mode, the sound from the front side (X side or -X side) can be collected with narrow directivity. it can.

《MS stereo zoom (sound pressure secondary gradient type) mode and MS stereo zoom (delay addition type) mode》
In the MS stereo zoom (sound pressure secondary gradient type) mode, the sound pressure secondary gradient type narrow directivity mode processing is performed on the sound signals from the unidirectional microphones 2A and 2B, and the sound signal after this processing is performed. Is a Mid signal, and an audio signal from the bi-directional microphone 3 is a Side signal to perform MS stereo processing.

  In the MS stereo zoom (delay addition type) mode, processing in the delay addition type narrow directivity mode is executed on the audio signals from the unidirectional microphones 2A and 2B, and the audio signal after this processing is set as a Mid signal. In this mode, the MS stereo method is executed using the audio signal from the directional microphone 3 as a Side signal.

<< MS Stereo Zoom (Sound Pressure Secondary Gradient Type) Mode and MS Stereo Zoom (Delayed Addition Type) Mode: Setting of Microphones 2A, 2B, 31, 32 >>
FIG. 15A is a top view of the sound collection device 1 in which the unidirectional microphone 2 is set in the MS stereo zoom (sound pressure secondary gradient type) mode, and FIG. 15B is a front view.

  Even in the MS stereo zoom (sound pressure secondary gradient type) mode, the microphone angles of the unidirectional microphones 2A and 2B are set similarly to the sound pressure secondary gradient type narrow directivity mode. In addition, both unidirectional microphones 31 and 32 are turned on.

  The distance d1 between the unidirectional microphones 2A and 2B is set in the same manner as in the above-described sound pressure secondary gradient type narrow directivity mode. Further, the distance d2 from the bidirectional microphone 3 to the unidirectional microphone 2A and the distance d3 from the unidirectional microphone d3 are set to be substantially the same. The reason for this is as follows.

  That is, as described above, in the MS stereo system, in order to achieve uniform sound collection, the center of the diaphragm for the Side signal microphone and the center of the diaphragm for the Mid signal microphone are arranged in the same manner. It is preferable. Here, in the MS stereo zoom (sound pressure secondary gradient type) mode, the audio signal s2 and the audio signal s1 having the opposite phase are added and synthesized. Here, the synthesized signal is assumed to be in the same position (that is, the center position between the unidirectional microphones 2A and 2B) when viewed from the two microphones (unidirectional microphones 2A and 2B). It is equivalent to picking up sound with a typical diaphragm.

  For this reason, in the MS stereo zoom (sound pressure secondary gradient type) mode, the bi-directional microphone 3 is disposed at the position of this virtual diaphragm, thereby being disposed close to an ideal state for the MS system. .

  FIG. 16A is a top view of the sound collection device 1 in which the unidirectional microphone 2 is set in the MS stereo zoom (delay addition type) mode, and FIG. 16B is a front view.

  In the MS stereo zoom (delay addition type) mode, the microphone angles of the unidirectional microphones 2A and 2B are set in the same manner as in the delay addition type narrow directivity mode. In addition, both unidirectional microphones 31 and 32 are turned on.

  In the MS stereo zoom (delay addition type) mode, the distance d1 between the unidirectional microphones 2A and 2B is set as in the delay addition type narrow directivity mode. At the same time, the unidirectional microphone 2 (in FIG. 15, the unidirectional microphone 2A) that does not delay the input audio signal is disposed closest to the bidirectional microphone 3.

  As described above, the center of the diaphragm of the bi-directional microphone 3 and the center of the diaphragm of the unidirectional microphones 2A and 2B are ideally arranged in the same manner. Since the time t1 is added to the audio signal input from the unidirectional microphone 2 (the unidirectional microphone 2B in FIG. 15) that delays the input audio signal, the unit that delays the input audio signal. The center of the diaphragm of the unidirectional microphone 2 is equivalent to the center of the diaphragm of the unidirectional microphone 2A that does not delay the input audio signal.

  For this reason, the unidirectional microphone 2 and the bidirectional microphone 3 that do not delay the input audio signal are arranged close to each other, so that the unidirectional microphones 2A and 2B and the bidirectional microphone 3 are arranged close to each other. It becomes a state. Thereby, the unidirectional microphones 2A and 2B and the bidirectional microphone 3 can be arranged in an almost ideal state.

<< MS stereo zoom (sound pressure secondary gradient type) mode and MS stereo zoom (delay addition type) mode: audio signal processing >>
FIG. 17A is a diagram for explaining audio signal processing in the MS stereo zoom (sound pressure secondary gradient type) mode, and FIG. 17B is an audio in the MS stereo zoom (delay addition type) mode. It is a figure for demonstrating signal processing. FIG. 18A is a block diagram illustrating a functional configuration of the signal processing unit 9 in the MS stereo zoom (sound pressure secondary gradient type) mode. FIG. 18B is a block diagram illustrating a functional configuration of the signal processing unit 9 in the MS stereo zoom (delay addition type) mode.

  In the MS stereo zoom (sound pressure secondary gradient type) mode, the signal processing unit 9 includes a gain adjustment unit 91-5, multiplication units 92-5, and 92 in addition to the multiplication unit 92-3 and the addition unit 93-3. -2C and adders 93-5A, 93-5B, 93-2E. In the MS stereo zoom (delay addition type) mode, the signal processing unit 9 includes, in addition to the addition unit 93-4 and the delay unit 94-4, a gain adjustment unit 91-5, multiplication units 92-5, 92-2C, and Adders 93-5A, 93-5B, and 93-2E are provided.

  In FIG. 18A, the signal processing unit 9 uses the multiplication unit 92-3 and the addition unit 93-3 for the sound pressure secondary gradient type narrowing with respect to the audio signal from the unidirectional microphones 2A, 2B. Executes directional mode processing. In FIG. 18B, the signal processing unit 9 uses the adder 93-4 and the delay unit 94-4 to apply the delay addition type narrow directivity mode to the audio signal from the unidirectional microphones 2A and 2B. Execute the process. The audio signals after these processes are referred to as audio signals s3 and s3 ′.

  Hereinafter, in common with FIGS. 18A and 18B, the signal processing unit 9 inputs the audio signals s3 and s3 ′ as Mid signals to the adding unit 93-5A and the adding unit 93-5B. At the same time, similarly to the MS stereo (−90 ° direction) mode, etc., a gain signal is generated by generating a Side signal from signals from the microphone 31 and the microphone 32 using the multiplier 92-2C and the adder 93-2E. Input to -5. The gain adjusting unit 91-5 adjusts the level of the input Side signal in order to adjust the level balance with the Mid signal, and inputs the level to the multiplying unit 92-5 and the adding unit 93-5A. The multiplier 92-5 multiplies the input Side signal by -1, and inputs the multiplied Side signal to the adder 93-5B.

  The adder 93-5A adds the Side signal to the input Mid signal to generate an R channel audio signal. The R channel audio signal is input to the D / A converter 10. The adder 93-5B adds the input Mid signal and the input Side signal × −1 to generate an L-channel audio signal. The L channel audio signal is input to the D / A converter 10.

  By collecting sound in the MS stereo zoom (sound pressure secondary gradient type) mode or the MS stereo zoom (delay addition type) mode, sound can be collected with narrow directivity in the X direction and -X direction. In addition, sound collection with a stereo feeling in the YY direction can be performed. Further, the zoom feeling can be adjusted by adjusting the mixing ratio of the Mid signal and the Side signal.

《Mono-opposite directional shaft rotation mode》
The mono-directional directional axis rotation mode is a mode in which the unidirectional microphones 2A and 2B function as a directional microphone in the XX direction, and a bidirectional directional microphone is formed at right angles with the bidirectional microphone 3. It is. In the mono-directional directional rotation mode, the sound from the bi-directional microphone in two directions is added, thereby forming the counter-directional axis and changing the mixing ratio of the sound from the bi-directional microphone in two directions. Thus, this is a mode in which the bi-directional counter directing axis is rotated.

<< Mono-opposing direct axis rotation mode: setting of each microphone 2A, 2B, 31, 32 >>
In the mono-directional directional axis rotation mode, the microphone angle of the unidirectional microphone 2A is set to -90 °, and the microphone angle of the unidirectional microphone 2B is set to be 90 ° (to face each other). The In addition, both unidirectional microphones 31 and 32 are turned on.

  In the mono-directional directional rotation mode, the unidirectional microphones 2A and 2B function like a bi-directional microphone, and therefore it is preferable that the unidirectional microphones 2A and 2B be as close as possible. Further, in order to rotate the opposing directional axis 360 degrees on a concentric circle, it is preferable that the bidirectional microphone 3 and the unidirectional microphones 2A and 2B are arranged close to each other. For this reason, in the mono-directional directional shaft rotation mode, the unidirectional microphones 2A and 2B are arranged closest to the bidirectional microphone 3 with the bidirectional microphone 3 set to the highest level. That is, the microphones 2A, 2B, 31, and 32 are set in the same manner as in FIGS.

<< Mono-opposite-oriented axis rotation mode: Audio signal processing >>
FIG. 19A is a diagram for explaining audio signal processing in the monaural opposed directional axis rotation mode. FIG. 19B is a block diagram showing a functional configuration of the signal processing unit 9 in the monaural opposed directional axis rotation mode shown in FIG. The signal processor 9 includes gain adjusters 91-6A and 91-6B, multipliers 92-6A and 92-6B, and adders 93-6A, 93-6B and 93-6C.

  The signal processing unit 9 inputs the audio signal s2 from the unidirectional microphone 2A to the adder 93-6A and inputs the audio signal s1 from the unidirectional microphone 2B to the multiplier 92-6A. The multiplier 92-6A multiplies the input audio signal s1 by -1 (in reverse phase) and inputs the result to the adder 93-6A. The adder 93-6A adds the audio signal s2 from the unidirectional microphone 2A and the audio signal s1 × -1 from the unidirectional microphone 2B to generate a bi-directional audio signal in the XX direction. A process of generating s4 is performed.

  The signal processing unit 9 inputs the audio signal s4 to the addition unit 93-6B via the gain adjustment unit 91-6A. At the same time, the signal processing unit 9 inputs the audio signal s5 from the bidirectional microphone 3 to the adding unit 93-6B via the gain adjusting unit 91-6B. Here, in order to make the unidirectional microphones 31 and 32 function as a bidirectional microphone, the signal processing unit 9 inputs the output of the microphone 32 to the adding unit 93-6C and multiplies the output of the microphone 31. Input to section 92-6B. The multiplier 92-6B multiplies the input signal of the microphone 31 by -1, and inputs the result to the adder 93-6C. The adder 93-6C adds the input output signal of the microphone 32 and the input output of the microphone 31 × −1 signal to generate an audio signal s5.

  The gain adjusting unit 91-6A and the gain adjusting unit 91-6B adjust the level balance by multiplying the input audio signal s4 and audio signal s5 by a predetermined coefficient. The coefficient of the gain adjustment unit 91-6A and the coefficient of the gain adjustment unit 91-6B are set to “1” when added together.

  The adder 93-6B receives the audio signal s4 and the audio signal s5 in a state where the level balance is adjusted, and adds the audio signal s4 and the audio signal s5. As a result, sound can be collected with a bi-directional counter directivity axis on a plane including the XX direction and the YY direction. Here, the mixing ratio of the audio signal s4 and the audio signal s5 can be changed by changing the coefficient of the gain adjusting unit 91-6A and the coefficient of the gain adjusting unit 91-6B. The axis can be rotated 360 degrees on a plane containing the XX and YY directions.

  In the monaural opposed directional axis rotation mode, as described above, a bidirectional opposed directional axis can be formed on the plane including the XX direction and the YY direction, and this directional axis can be rotated. The pointing direction can be rotated 360 degrees on the surface by simple processing.

<Pair microphone stereo (combined level difference / phase difference) mode>
The pair microphone stereo (level difference / phase difference combined use) mode is a mode for performing stereo sound collection using the level difference / phase difference of the sound input to the unidirectional microphones 2A, 2B.

<< Paired microphone stereo (both level difference and phase difference) mode: setting of each microphone 2A, 2B, 31, 32 >>
FIG. 20A is a diagram showing settings of the unidirectional microphones 2A and 2B in the pair microphone stereo (level difference / phase difference combined use) mode.

  The unidirectional microphone 2A is disposed at the −X side end, and the unidirectional microphone 2B is disposed at the X side end. Furthermore, in order to set the opening angle θ between the unidirectional microphones 2A and 2B to a predetermined opening angle between 90 degrees and 120 degrees (for example, 110 degrees), the unidirectional microphone 2A The microphone angle is set to 0 ° to 90 °. Further, the microphone angle of the unidirectional microphone 2B is set to 0 ° to −90 °.

  In addition, when the unidirectional microphones 2A and 2B are arranged at the opening angle θ at the predetermined opening angle and at the opposite ends as described above, the unidirectional microphones 2A and 2B The lengths in the front-rear direction of the slits 11A and 11B and the unidirectional microphones 2A and 2B are set so that the distance d4 between the front centers is approximately 17 cm. Accordingly, the unidirectional microphones 2A and 2B can be set to a suitable arrangement (the arrangement shown in FIG. 20A) in the pair microphone stereo (both level difference / phase difference combination) mode for easy positioning.

  The bi-directional microphone 3 is normally turned off, but when a hollow is a concern, a microphone that faces the directional axis to prevent the hollow (microphone 32 in the case of FIG. 20A). It may be configured to be mixed only by turning on the level and adjusting the level.

  Further, as described above, the sound collection device 1 is used as a boundary microphone by installing the back surface of the sound collection device 1 on the floor surface.

  FIG. 20B is a diagram showing settings of the unidirectional microphones 2A and 2B in the pair microphone stereo (both level difference / phase difference combination) mode when the sound collection device 1 is used as a boundary microphone.

  Also in this case, the unidirectional microphone 2A is disposed at the −X side end, and the unidirectional microphone 2B is disposed at the X side end. Then, the opening angle θ can be adjusted to a predetermined opening angle (for example, 110 °) by rotating the unidirectional microphones 2A and 2B in the BB direction. By adjusting in this way, stereo sound can be collected by the boundary microphone.

  Furthermore, as shown in FIG. 20C, the sound collecting direction may be set so that the unidirectional microphone 2A is rotated in the AA direction and is directed to the height of the sound source. In this case, it is preferable that the height from the floor surface to the diaphragm of the unidirectional microphone 2 is set to be smaller than a quarter wavelength of the specific frequency described above.

  It should be noted that the main axis of the bidirectional microphone 3 can be directed upward (in the -Y direction when the back surface is installed on the floor as shown in FIG. 20B). The structure which prevents the omission of the sound from between the unidirectional microphones 2A and 2B by performing sound may be used.

  For example, as shown in FIG. 21, the bidirectional microphone 3 is pivotally supported by a shaft 3B ′ extending in the direction of the unidirectional microphones 2A and 2B. At the same time, the shaft 3B ′ is rotatably attached to the end of the bowl-shaped support portion 3A ′. Thus, the bi-directional microphone 3 (unidirectional microphone 31 or unidirectional microphone 32) is moved upward (in the −Y direction in FIG. 20B) by rotating the shaft 3B ′. It can be rotated. In this state, by collecting sound from the bidirectional microphone 3 as well, it is possible to prevent sound from being lost between the unidirectional microphones 2A and 2B as described above.

《Pair microphone stereo (with both level difference and phase difference) mode: Audio signal processing》
The audio signal processing in the pair microphone stereo (both level difference / phase difference combination) mode is a normal pair microphone stereo (both level difference / phase difference combination) type audio signal processing, and thus description thereof is omitted.

  By the pair microphone stereo (level difference / phase difference combined use) mode, sound can be collected by a stereo (level difference / phase difference combined use) method by changing the opening angle θ between the unidirectional microphones 2A and 2B. .

<< Pair microphone stereo (XY level difference) mode >>
The pair microphone stereo (XY level difference) mode is a mode for performing stereo sound collection including only the level difference without including the phase difference and time difference of the sound input to the unidirectional microphones 2A and 2B as much as possible.

<< Pair microphone stereo (XY level difference) mode: setting of each microphone 2A, 2B, 31, 32 >>
FIG. 22A is a top view of the sound collection device 1 in which the unidirectional microphone 2 is set in the pair microphone stereo (XY level difference) mode, and FIG. 22B is a front view.

  In the pair microphone stereo (XY level difference) mode, the unidirectional microphones 2A and 2B are arranged as close as possible so that there is no phase difference or time difference between the sounds input to the unidirectional microphones 2A and 2B. Therefore, it is preferable. Therefore, the bidirectional microphone 3 is set to the highest level, and the unidirectional microphones 2A and 2B are slid to the end of the slit 11 on the bidirectional microphone 3 side, so that the lower portion of the bidirectional microphone 3 is Placed in.

  In this state, the opening angle θ between the unidirectional microphones 2A and 2B is set to a predetermined angle (for example, 110 °) between 90 ° and 120 °. The microphone angle of the unidirectional microphone 2A is set to 180 ° to 270 °. Further, the microphone angle of the unidirectional microphone 2B is set to 90 ° to 180 °. The bi-directional microphone 3 is normally turned off. However, when a hollow hole is a concern, a microphone that faces the directional axis to prevent a hollow hole (in the case of FIG. 22A, the microphone 31). It may be configured to be mixed only by turning on the level and adjusting the level.

<< Pair microphone stereo (XY level difference) mode: Audio signal processing >>
The audio signal processing in the pair microphone stereo (XY level difference) mode is a normal XY stereo audio signal processing, and thus description thereof is omitted.

  In the pair microphone stereo (XY level difference) mode, sound can be collected in the XY stereo system by changing the microphone angles of the unidirectional microphones 2A and 2B.

<Additional monaural narrow directivity mode>
In the addition type monaural narrow directivity mode, the sound collecting directions of the unidirectional microphones 2A and 2B and the bidirectional microphone 3 are all directed to the same direction, and the audio signals from these microphones 2A, 2B and 3 are added. This is a mode in which sound is collected with narrow directivity in the direction in which each microphone 2A, 2B, 3 faces.

<< Additional monaural narrow directivity mode: setting of each microphone 2A, 2B, 31, 32 >>
FIG. 23 is a top view of the sound collection device 1 in which the unidirectional microphone 2 is set in the addition type monaural narrow directivity mode. When sound is collected with a narrow directivity in the −Y direction, the sound collection angle of the unidirectional microphones 2A and 2B is set to 0 °.

Furthermore, the unidirectional microphone 32 is turned on and the unidirectional microphone 31 is turned off.

Further, when collecting sound with narrow directivity in the Y direction, the sound collection angle of the unidirectional microphones 2A and 2B is set to 180 °. At the same time, the unidirectional microphone 31 is turned on and the unidirectional microphone 32 is turned off.

  Furthermore, the distance d5 in the XX direction between the unidirectional microphone 2A and the bidirectional microphone 3 and the XX direction between the unidirectional microphone 2B and the bidirectional microphone 3 in the XX direction. By adjusting the distance d6, sound can be picked up by changing the directivity and frequency characteristics.

<< Additional monaural narrow directivity mode: Audio signal processing >>
FIG. 24A is a diagram for explaining audio signal processing in the addition type monaural narrow directivity mode. FIG. 24B is a block diagram showing a functional configuration of the signal processing unit 9 in the addition type monaural narrow directivity mode. The signal processing unit 9 includes a gain adjustment unit 91-7, an addition unit 93-7, and delay units 94-7A and 94-7B.

  The signal processing unit 9 inputs the audio signal from the unidirectional microphone 32 to the gain adjustment unit 91-7. The gain adjustment unit 91-7 adjusts the gain of the input audio signal from the unidirectional microphone 32 to add a level balance with the audio signals from the unidirectional microphones 2A and 2B. Input to 93-7.

  Further, the signal processing unit 9 inputs the audio signal from the unidirectional microphone 2A to the delay unit 94-7A and inputs the audio signal from the unidirectional microphone 2B to the delay unit 94-7B. There is a distance d (of the diaphragm) in the YY direction between the unidirectional microphone 32 and the unidirectional microphone 2. The delay units 94-7A and 94-7B delay the input audio signal at the time difference t2 of the audio input timing based on the distance d and input the delayed audio signal to the adder 93-7.

  The adder 93-7 adds and synthesizes the audio signal from the input unidirectional microphone 32 and the audio signals from the delayed unidirectional microphones 2 </ b> A and 2 </ b> B and inputs the resultant signal to the D / A converter 10. To do. As a result, sound can be collected with a narrow directivity in the Y direction or the -Y direction.

  Since sound can be collected in the addition type monaural narrow directivity mode, the above-described sound pressure secondary gradient type narrow directivity mode or the delay addition type narrow directivity mode, the sound collection device 1 has the X direction, -X direction, Sound can be collected with narrow directivity in the Y and −Y directions.

<Description of mode setting process>
FIG. 25 is a flowchart showing the mode setting process executed by the control unit 8. This process is started when an operation signal indicating a mode selection operation (an operation signal corresponding to pressing of the operation button 41) is input to the control unit 8. First, the control unit 8 detects a sound collection mode indicated by the input operation signal (S1). The control unit 8 reads a program corresponding to the detected sound collection mode from the storage unit 7 (S2).

  The control unit 8 sets the read program in the signal processing unit 9 and switches on / off setting of the unidirectional microphones 31 and 32 (S3). The signal processing unit 9 in which the program is set changes the audio signal processing setting in accordance with the program, and then inputs a completion signal indicating the completion of this processing to the control unit 8.

  Thereafter, the control unit 8 determines whether or not a completion signal has been input within a predetermined time (S4), and if it is determined that a completion signal has been input within a predetermined time (YES in S4), this process is performed. Terminate. On the other hand, when it is determined that the completion signal has not been input within the predetermined time (NO in S4), the control unit 8 displays an error on the display unit 4A, for example (S5), and thereafter ends this processing. Let

  As described above, in the sound collection device 1 according to the present embodiment, the sound collection angles of the unidirectional microphones 2A and 2B can be individually changed, so that there are variations in the directivity setting pattern of each microphone. It becomes more abundant than the prior art, and this allows the sound collection device 1 to be compatible with various sound collection methods.

  The sound collection angles of the unidirectional microphones 2A and 2B can be changed in the AA direction, and the unidirectional microphones 2A and 2B can be slid in the XX direction. Therefore, the positional relationship between the unidirectional microphones 2A and 2B and the positional relationship between the unidirectional microphone 2 and the bidirectional microphone 3 are set so as to be optimal for various sound collection modes and easily positioned. be able to.

  In addition, since the unidirectional microphones 2A and 2B are rotatable about two axes (rotating axes a and b) and rotate not only in the AA direction but also in the BB direction, for example, the boundary Stereo microphones can be collected with a microphone, and a wider variety of sounds can be collected.

  Further, since the position of the bidirectional microphone 3 can be freely changed in the height direction, it can be made compact by arranging it close to the apparatus main body 1B side during storage, and each sound collection mode can be used during sound collection. The height of the bidirectional microphone 3 can be set at a suitable position.

  Note that the sound collection device according to the present invention may not be compatible with all of the various sound collection modes described above, and further, various sound collection modes, and microphone angles and audio signal processing contents corresponding to the various sound collection modes. Is not limited to the above.

It is a perspective view which shows the external appearance of the sound collection device concerning embodiment of this invention. It is a front view of the sound collection device shown in FIG. (A) is a figure which shows attachment of a support part and a unidirectional microphone, (b) is side sectional drawing which shows the structure of the unidirectional microphone shown in FIG. 1, a support part, and these peripheral parts. (C) is an ee cross-sectional view of the unidirectional microphone shown in (b). It is a block diagram which shows the structure of the sound collection device shown in FIG. (A) is a top view of the sound collection apparatus which set the unidirectional microphone to MS stereo (0 degree direction) mode, (b) is a front view. (A) is a figure for demonstrating the audio | voice signal in MS stereo (0 degree direction) mode, (b) is a block which shows the function of the signal processing part 9 in MS stereo (0 degree direction) mode. FIG. (A) is a figure for demonstrating the audio | voice signal processing in MS stereo (-90 degree direction) mode, (b) is a functional of the signal processing part in MS stereo (-90 degree direction) mode. It is a block diagram which shows a structure. (A) is a figure for demonstrating the audio | voice signal processing in MS surround (0 degree direction) mode, (b) is a functional structure of the signal processing part in MS surround (0 degree direction) mode. FIG. (A) is a figure for demonstrating the audio | voice signal processing in MS surround (-90 degree direction) mode, (b) is a functional of the signal processing part in MS surround (-90 degree direction) mode It is a block diagram which shows a structure. (A) is a top view of the sound collection device which set the unidirectional microphone to the sound pressure secondary gradient type narrow directivity mode, and (b) is a front view. It is a graph which shows the frequency characteristic in a sound pressure secondary gradient type narrow directivity mode, (a) is a graph in case distance d1 / 2 is 0.034m, (b) is distance d1 / 2 is 0.068m. It is a graph in the case of. It is a graph which shows the frequency characteristic in a delay addition type | mold narrow directivity mode, (a) is a graph in case distance d1 / 2 is 0.034m, (b) is a case in case distance d1 / 2 is 0.068m. It is a graph. It is a figure for demonstrating the audio | voice signal process in a sound pressure secondary gradient type | mold narrow directional mode and a delay addition type | mold narrow directional mode. (A) is a block diagram showing a functional configuration of the signal processing unit in the sound pressure secondary gradient type narrow directivity mode shown in FIG. 13, and (b) is a block diagram in the delay addition type narrow directivity mode shown in FIG. It is a block diagram which shows the functional structure of a signal processing part. (A) is a top view of the sound collection apparatus which set the unidirectional microphone to MS stereo zoom (sound pressure secondary gradient type) mode, (b) is a front view. (A) is a top view of the sound collection apparatus which set the unidirectional microphone to MS stereo zoom (delay addition type) mode, (b) is a front view. (A) is a figure for demonstrating the audio | voice signal process in MS stereo zoom (sound pressure secondary gradient type) mode, (b) is the audio | voice signal process in MS stereo zoom (delay addition type) mode. It is a figure for demonstrating. (A) is a block diagram showing a functional configuration of a signal processing unit in the MS stereo zoom (sound pressure secondary gradient type) mode, and (b) is a signal processing unit in the MS stereo zoom (delay addition type) mode. It is a block diagram which shows the functional structure of these. (A) is a figure for demonstrating the audio | voice signal processing of a monaural opposing directional axis | shaft rotation mode, (b) is a functional of the signal processing part in the monaural opposite directional axis | shaft rotation mode shown in FIG. It is a block diagram which shows a structure. (A) is a figure which shows the setting of the unidirectional microphone in a pair microphone stereo (level difference and phase difference combined use) mode, (b) is a pair microphone stereo in the case of using a sound-collecting apparatus as a boundary microphone. It is a figure which shows the setting of the unidirectional microphone in (level difference and phase difference combined use) mode, (c) is a sound collection device shown by (b), Comprising: A unidirectional microphone is AA It is a figure which shows the thing of the state rotated also in the direction. It is a figure which shows the bidirectional microphone and its peripheral member concerning the modification of this embodiment. (A) is a top view of the sound collection apparatus which set the unidirectional microphone to the pair microphone stereo (XY level difference) mode, (b) is a front view. (It is a top view of the sound collection device in which the unidirectional microphone 2 is set in the addition type monaural narrow directivity mode. (A) is a figure for demonstrating the audio | voice signal processing in addition type monaural narrow directivity mode, (b) is a block diagram which shows the functional structure of the signal processing part in addition type monaural narrow directivity mode. is there. It is a flowchart which shows the mode setting process which a control part performs.

Explanation of symbols

1-Sound pickup device 1A-Device main body 2 (2A, 2B)-Unidirectional microphone 3-Bidirectional microphone 3A-Support part (corresponding to the second support part of the present invention) 21 (21A, 21B)-Support Part a, b-Rotating shaft

Claims (6)

Two unidirectional microphones provided so as to be rotatable around two rotation axes parallel to each other;
A support portion for supporting the rotation axis of the two unidirectional microphones so as to be movable in a predetermined section on a straight line connecting the rotation axes;
A sound collecting device comprising: A bi-directional microphone provided on the straight line so that the straight line and the directivity axis are at right angles;
A second support portion for supporting the bidirectional microphone so as to be movable in a direction parallel to the rotation axis;
The sound collecting device according to claim 1, further comprising: The unidirectional microphone is rotatably supported on a second axis perpendicular to the rotation axis.
The sound collection device according to claim 1, wherein the sound collection device is a sound collection device. Two unidirectional microphones provided so as to be rotatable about two axes around two rotation axes parallel to each other and a second axis perpendicular to the rotation axis;
The device body;
A support unit attached to the apparatus body and supporting the unidirectional microphone;
A sound collecting device comprising: The apparatus main body is a side surface parallel to the rotation axis, and the distance to the rotation axis is a distance equal to or less than ¼ of the wavelength of a sound wave of a specific frequency
The sound collection device according to claim 4. Two unidirectional microphones provided so as to be rotatable around two rotation axes parallel to each other;
A bidirectional microphone in which the straight line and the directivity axis are provided at right angles on a straight line connecting the two rotation axes;
A second support portion for supporting the bidirectional microphone so as to be movable in a direction parallel to the rotation axis;
A sound collecting device comprising:

Images