Listening sound acquisition method and listening sound acquisition device

Abstract

A listening sound acquisition method according to the present invention is for a loudspeaker system that delivers spoken sound from a speaker to a listener via a loudspeaker transmission path that includes a sound collection means, an amplification means, and a sound emission means. The method involves acquiring the sound pressure of the spoken sound at an arbitrary location on the transmission path and finding the sound pressure at a listening location for the listener on the basis of the acquired sound pressure.

Description

Method and device for acquiring audible sound

[0001] An embodiment of the present invention relates to a method and an apparatus for acquiring audible sound.

[0002] In a conference system, a means for amplifying speech sounds and transmitting them to conference participants is provided in the conference room so that all conference participants can clearly hear the speech sounds. In this type of conference system, the speech sounds must be amplified so that the speech sounds of the speaker reach the listeners with sufficient sound pressure. Patent Document 1, which relates to remote control, discloses a technology for notifying the implementation status of the amplification in an area where the speech sounds are amplified.

[0003] Japanese Patent Application Laid-Open No. 2001-245365

[0004] However, the technology of Patent Document 1 only notifies the implementation status of the loudspeaker, and even if this notification is received, it is difficult to determine whether the speech sound is reaching the listener with sufficient sound pressure.

[0005] One embodiment of the present invention has been made in view of the above circumstances, and has an object to provide a method for acquiring audible sound that acquires the sound pressure of an uttered sound.

[0006] A method for acquiring audible sounds according to one embodiment of the present invention is a method for acquiring audible sounds in a public address system that delivers a speaker's speech to a listener via a public address transmission path including a sound collection means, an amplification means, and a sound emission means, and acquires sound pressure at any position on the transmission path of the speech sound, and calculates the sound pressure at the listener's listening position based on the acquired sound pressure.

[0007] 1 is a block diagram showing the configuration of a narrated sound acquisition device and a conference system that executes a narrated sound acquisition method that is an embodiment of the present invention. FIG. 2 is a block diagram showing the hardware configuration of the narrated sound acquisition device 200. FIG. 3 is a diagram showing an example of the configuration of a transmission system of an uttered sound in the embodiment. FIG. 4 is a block diagram showing a transmission system of the same. FIG. 5 is a block diagram showing a transmission method of an uttered sound in the same transmission system. FIG. 6 is a block diagram showing a generalized transmission system of an uttered sound in the embodiment. FIG. 7 is a block diagram showing transmission paths that constitute the transmission system. FIG. 8 is a block diagram showing a narrated sound acquisition method in the transmission system. FIG. 9 is a diagram showing an example of an information providing unit in the embodiment. FIG. 10 is a flowchart of a narrated sound acquisition process that is executed in the embodiment. FIG. 11 is a block diagram showing a narrated sound acquisition method that is another embodiment of the present invention. FIG. 12 is a diagram showing a modified example of visible information. FIG. 13 is a diagram showing a modified example of visible information. FIG. 14 is a schematic side view of a conference room. FIG. 15 is a diagram showing a further modified example of visible information. FIG. 16 is a diagram showing a further modified example of visible information.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] 1 is a block diagram showing the configuration of a listening sound acquisition device 200 that executes a listening sound acquisition method according to an embodiment of the present invention, and a loudspeaker system 100. In this embodiment, acquiring a listening sound means acquiring information on the sound pressure (spm) of the listening sound.

[0010] The method for acquiring audible sound according to this embodiment is directed to a public address system 100 shown in Fig. 1 . The public address system 100 of this embodiment is a system that amplifies the voice of a speaker and delivers the voice to listeners, and is used, for example, in conferences, seminars, presentations, etc. In this embodiment, an example is shown in which the public address system 100 is used in a conference. In the public address system 100, the speech sound of a conference participant Mi who is a speaker reaches a conference participant Mj who is a listener via a public address transmission path 10 including a sound collection means 11, an amplification means 12, and a sound emission means 13, and the speech sound also reaches the conference participant Mj via a direct transmission path 20 that does not include the public address transmission path 10.

[0011] In such a loudspeaker system 100, the audible sound acquisition device 200 acquires the audible sound of the conference participant M who is a listener. ｊ 1 as an external device of the loudspeaker system 100, it may also be a device included in a control device (not shown) of the loudspeaker system 100.

[0012] 2 is a block diagram showing the hardware configuration of the audible sound acquisition device 200. The audible sound acquisition device 200 is, for example, a general-purpose information processing device such as a personal computer or a smartphone. The general-purpose information processing device may be a device used by a speaker, or may be a device used by an operator who runs a conference or an installer who installs a conference system.

[0013] The audible sound acquisition device 200 includes a display 251 , a user I / F 252 , a flash memory 253 , a CPU 254 , a RAM 255 , and a communication I / F 256 .

[0014] The display 251 is, for example, an LCD or an OLED, and displays various information. The user I / F 252 is, for example, a touch panel that is stacked on the LCD or OLED of the display 251. Alternatively, the user I / F 252 may be a keyboard, a mouse, or the like. When the user I / F 252 is a touch panel, the user I / F 252, together with the display 251, constitutes a GUI (Graphical User Interface).

[0015] The communication I / F 256 is a communication means such as a wireless LAN, Bluetooth (registered trademark), etc. The communication I / F 256 receives sound signals from the loudspeaker system 100, for example.

[0016] The CPU 254 is an example of a processor, and is a control unit that controls the operation of the audible sound acquisition device 200. The CPU 254 performs various operations by reading predetermined programs, such as application programs, stored in a flash memory 253, which is a storage medium, into a RAM 255 and executing the programs. The CPU 254 of this embodiment realizes the functions of the control unit 201, the measurement unit 202, and the information providing unit 203 shown in FIG. 1 . The programs may be stored in a server (not shown). The CPU 254 may download and execute the programs from the server via a network.

[0017] As shown in Fig. 1, the audible sound acquisition device 200 includes a control unit 201, a measurement unit 202, and an information providing unit 203. Here, the measurement unit 202 is a means for measuring the sound pressure at any position on the transmission path of the speech sound in the public address system 100. The control unit 201 includes a processor, a non-volatile memory that stores a program executed by the processor, and a volatile memory used as a work area by the processor. The control unit 201 calculates the sound pressure measured by the measurement unit 202 and determines the sound pressure of the conference participant M who is a listener. ｊ The control unit 201 also determines the relationship of the sound pressure of the speech sound to an appropriate value based on the sound pressure at the listening position, and provides visible information indicating the determination result via the information providing unit 203.

[0018] Fig. 3 is a diagram showing an example of a transfer system for speech sounds in the public address system 100. Fig. 4 is a block diagram expressing the transfer system using a transfer function.

[0019] In this example, a microphone 11a as the sound collection means 11, an amplifier 12a as the amplification means 12, and a speaker 13a as the sound emission means 13 are arranged on the ceiling 301 of the conference room 300. ｉ The voice is transmitted from the speaking position (for example, the position of the head) of the conference participant M via the microphone 11a, the amplifier 12a, and the speaker 13a. ｊ The route from the speaker 10 to the listening position (for example, the head position) of the conference participant M is the amplification transmission route 10. ｉ From the speaking position of the conference participant Mｊ The path from the first to the listening position is the direct transmission path 20.

[0020] In this example, the sound pressure of the speech sound at the speaking position is sp0, and the transfer function from the speaking position to the sound pickup part of the microphone 11a is H ２ , the total gain of the microphone 11a, the amplifier 12a, and the speaker 13a is G, and the transfer function from the sound emitting part of the speaker 13a to the listening position is H. ３ Then, the sound pressure sp4 of the sound that reaches the listening position via the sound amplification transmission path 10 is expressed by the following formula:

[0021] sp4=H ２ G.H. ３ On the other hand, the transfer function of the direct transfer path 20 is H １ Then, the sound pressure sp1 of the sound that reaches the listening position via the direct transmission path 10 is expressed by the following equation.

[0022] sp1=H １ sp0 (2) Therefore, the sound pressure sp5 of the listened sound at the listening position is given by the following formula.

[0023] sp5=sp1+sp4=(H ２ G.H. ３ +H １ )·sp0 (3) In the transmission system shown in FIGS. 3 and 4, if the input sound pressure of microphone 11a is sp2, this sound pressure sp2 is the sound pressure at a position on the transmission path of the speech sound, and is expressed by the following equation.

[0024] sp2=H ２ sp0 (4) Here, the sound pressure sp0 can be calculated backward from the sound pressure sp2 using the following formula.

[0025] sp0=H ２ －１ sp2 (5) Therefore, the control unit 201 of the audible sound acquisition device 200 measures the sound pressure sp2 using the measurement unit 202, and calculates the following equation based on the measured sound pressure sp2 to obtain the sound pressure sp5 at the listening position.

[0026] sp5 = (H ２ G.H. ３ +H １ ) · sp0 = (H ２ G.H. ３ +H １ ) H ２ －１ sp2 (6) FIG. 5 is a block diagram showing the calculation content of this equation (6).

[0027] Next, the function of the audible sound acquisition device 200 will be described in more general terms. Fig. 6 is a block diagram showing a transmission system of speech sounds in a public address system 100 in which the number of conference participants N is 8. In this public address system 100, normally, N conference participants M ｉ Any one of the participants (i=1 to N) will be the speaker, and the remaining N-1 participants will be the listeners. ｉ N horizontal lines (N=8 in this example) connected to the conference participants M ｉ 6 shows the propagation paths of sounds uttered by conference participants M (i=1 to N). ｊ N vertical lines are shown connected to the conference participants M ｊ (j=1 to N) and the propagation path of the sound heard by the conference participant M ｉ (i=1 to N) and each horizontal line connected to the conference participant M ｊ At each intersection of each vertical line connected to (j=1 to N and j≠i), a transfer function H ｉｊ This transfer function H ｉｊ is the conference participant M ｉ and M ｊ (j≠i) is a transfer function of a transfer path in which the loudspeaker transfer path 10 and the direct transfer path 20 are connected in parallel. ｉ The speech sound is expressed by the transfer function H ｉｊ The conference participant M, who is a listener, ｊ to reach.

[0028] FIG. 7 shows the conference participant M ｉ and M ｊ(j≠i) Transfer function H of the transfer path between ｉｊ In this embodiment, the transfer path includes a transfer path for transmitting speech sounds. Here, the transfer function Hm ｉｊ is the transfer function H ｉｊ is a transfer function that represents a part of the sound pressure at an arbitrary position, where spm represents the sound pressure at an arbitrary position. This allows the audible sound acquisition device 200 to acquire the sound pressure (spm) at an arbitrary position on the transmission path of the speech sound, and to calculate the sound pressure at the listening position of the listener based on the acquired sound pressure. Specifically, if the audible sound acquisition device 200 can acquire the sound pressure spm, it can calculate the transfer function Hm ｉｊ Using the inverse function of ｉ can be obtained.

[0029] sp ｉ = Hm ｉｊ ―１ ・spm...(7) sp ｉ Once is found, sp ｊ can be obtained. ｊ = H ｉｊ ・sp ｉ = H ｉｊ ・Hm ｉｊ ―１ spm (8) In this embodiment, the control unit 201 executes the calculation shown in the above formula (8) based on the sound pressure spm, and calculates the sound pressure of the conference participant M ｊ Sound pressure sp at listening positions (N-1 locations) (j = 1 to N and j ≠ i) ｊ Ask for.

[0030] FIG. 8 is a block diagram showing the operation of equation (8).

[0031] The correspondence between this generalized embodiment and the above-described embodiments of FIGS. 3 and 4 is, for example, as follows.

[0032] <Example 1: When spm = sp2> spm = sp2 Hm ｉｊ = H ２ sp ｉ = sp0 sp ｊ = sp5 H ｉｊ = H ２ G.H.３ +H １ <Example 2: When spm = sp4> spm = sp4 Hm ｉｊ = H ２ ・G・H ３ sp ｉ = sp0 sp ｊ = sp5 H ｉｊ = H ２ G.H. ３ +H １ Using the above examples 1 and 2, sp ２ If the sound pressure is obtained at the position ｉｊ = H ２ and sp ４ If the sound pressure is obtained at the position ｉｊ = H ２ G.H. ３ As described above, the inverse function Hm ｉｊ ―１ In this embodiment, in order to obtain the sound pressure at the listening position, ｉ and M ｊ (j≠i) Transfer function H of the transfer path between ｉｊ and the transfer function Hm of the transfer path that generates the monitor sound ｉｊ In this embodiment, when the public address system 100 is installed, the conference participants M ｉ The head positions of (i=1 to N) are determined, and the characteristics of each part of the sound transmission path 10 are optimized based on the positions. ｉｊ and Hm ｉｊ Therefore, in this embodiment, when the public address system 100 is installed, the transfer function H ｉｊ and Hm ｉｊ is generated and stored in the nonvolatile memory of the control unit 201. Then, when the public address system 100 is in operation, the control unit 201 uses the stored transfer function H ｉｊ and Hm ｉｊ This is used to obtain the sound pressure at the listening position.

[0033] In this embodiment, in order to obtain the sound pressure at the listening position, the conference participant M ｉThe transfer function H ｉｊ and Hm ｉｊ Therefore, it is necessary to use the following. ｉ There are various possible means for detecting the speaker, but for example, if the microphone 11a placed in the conference room 300 is a microphone whose directivity can be controlled so as to pick up the speech sound with a high gain, the speaker may be detected using this microphone. Also, if it is difficult to detect the speaker using the microphone 11a, for example, the speaker may be detected by the conference participant M in the conference room 300. ｉ (i=1 to N) may be captured by a camera, and a recognition process may be performed on the captured image to detect a conference participant who is speaking.

[0034] When the control unit 201 acquires the sound pressure at N-1 listening positions, it determines the relationship of the sound pressure of the speech sound to the appropriate value based on the acquired sound pressure, and provides visible information indicating the determination result via the information providing unit 203.

[0035] FIG. 9 is a diagram showing an example of the information providing unit 203. This information providing unit 203 has an appropriate lamp 203a labeled with the word "appropriate," an under-sounding lamp 203b labeled with the word "under-sounding," and an over-sounding lamp 203c labeled with the word "over-sounding." In a preferred embodiment, the appropriate lamp 203a, the under-sounding lamp 203b, and the over-sounding lamp 203c light up in different colors. The information providing unit 203 is disposed, for example, near the sound emitting unit. The information providing unit 203 may be disposed anywhere as long as it can be easily confirmed by the speaker. For example, the information providing unit 203 may be disposed in a position that is easily visible when the speaker is speaking. Specifically, if the information providing unit is disposed at the position of the speaker, the speaker can confirm that they are speaking at an appropriate sound pressure by looking at the speaker from which sound is actually being emitted. Furthermore, if the information providing unit is placed at a position close to the speaker, the speaker can check their hand to confirm that they are speaking at an appropriate sound pressure. For example, the information providing unit 203 may be placed at a position that can be easily confirmed by an installer when installing the public address system. Specifically, if the information providing unit is provided on the screen of a computer used by the installer, the installer can easily check their computer during the installation work to confirm that they are speaking at an appropriate sound pressure.

[0036] When the sound pressures at all N-1 listening positions are within the appropriate range, the control unit 201 turns on the appropriate lamp 203a. Furthermore, when the sound pressure at at least one of the N-1 listening positions is below the lower limit of the appropriate range, the control unit 201 turns on the insufficient lamp 203b. In this case, the speaker increases the speech sound pressure. Furthermore, when the sound pressure at at least one of the N-1 listening positions is above the upper limit of the appropriate range, the control unit 201 turns on the excessive lamp 203c. In this case, the speaker decreases the speech sound pressure.

[0037] Next, the operation of this embodiment will be described. In this embodiment, the processor of the control unit 201 repeatedly executes the audible sound acquisition process P200 shown in Fig. 10 in accordance with a program stored in the nonvolatile memory.

[0038] First, the processor of the control unit 201 determines whether or not speech has been detected (step S1). This determination is made based on, for example, the sound collection state of the sound collection unit 11 (specifically, whether or not speech sounds are being collected, and which conference participant's speech sounds are being collected). If the determination result of step S1 is "NO," the processor of the control unit 201 repeats the determination of step S1.

[0039] If the determination result in step S1 is "YES", the processor of the control unit 201 measures the sound pressure spm of the monitor sound at a position on the transmission path of the speech sound of the conference participant who is speaking using the measurement unit 202 (step S2).

[0040] Next, the processor of the control unit 201 selects the conference participant M who is the speaker. ｉ The transfer function H ｉｊ and Hm ｉｊ －１ and the sound pressure spm of the monitor sound obtained in step S2, the sound pressure SP at the N-1 listening positions is calculated. ｊ (j=1 to N and j≠i) is calculated (step S3).

[0041] Next, the processor of the control unit 201 calculates the sound pressure SP at each listening position calculated in step S3. ｊ Based on the values ​​of j=1 to N and j≠i, the relationship of the sound pressure of the speech sound to the appropriate value is determined, and visual information indicating the determination result is provided to the speaker by the information providing unit 203 (step S4). When step S4 is completed, the process returns to step S1.

[0042] In this embodiment, the processes of steps S1 to S4 are repeated as described above. When an utterance is made, the sound pressure at each listening position is calculated, and based on the calculation result, the relationship of the sound pressure of the utterance sound to the appropriate value is determined, and the determination result is shown to the speaker. Therefore, the speaker can change the sound pressure of the utterance so that the sound reaches each listener at an appropriate sound pressure.

[0043] Although one embodiment of the present invention has been described above, other embodiments of the present invention are also possible. For example, the following embodiments are possible.

[0044] (1) In the above embodiment, the narrated sound acquisition device 200 measured the sound pressure of the input sound of the sound collection means 11 (sp2 in FIG. 3 ) and calculated the sound pressure at the listening position based on this measured sound pressure. However, the narrated sound acquisition device 200 may also calculate the sound pressure at the listening position based on a sound pressure other than the sound pressure of the input sound of the sound collection means 11. For example, the narrated sound acquisition device 200 may measure the sound pressure of the output sound of the sound emitting means 13 (sp3 in FIG. 3 ) and calculate the sound pressure at the listening position based on this measured sound pressure. Alternatively, the narrated sound acquisition device 200 may measure the sound pressure of the input sound of the sound collection means 11 (sp2 in FIG. 3 ) and the sound pressure of the output sound of the sound emitting means 13 (sp3 in FIG. 3 ) and calculate the sound pressure at the listening position based on this measured sound pressure. Alternatively, the heard sound acquisition device 200 may measure the sound pressure of the speech sound at the speaking position (sp0 in FIG. 3) and obtain the sound pressure at the listening position by calculation based on this measured sound pressure.

[0045] (2) In the above embodiment, the audible sound acquisition device 200 uses a predetermined transfer function H ｉｊ and Hm ｉｊ －１ However, the sound pressure at the listening position can be obtained by capturing an image using a camera or measuring the distance using LiDAR (Light Detection and Ranging). ｉThe head positions (i.e., speaking positions and listening positions) of the participants (i = 1 to N) may be obtained, and a transfer function of the transfer path between each of the conference participants may be generated based on these head positions. The heard sound acquisition device 200 may also measure environmental information such as the position of the room walls and the material (reflectance) of the walls by capturing images with a camera or measuring distances with LiDAR, and generate a transfer function of the transfer path between each of the conference participants based on the environmental information. More specifically, the heard sound acquisition device 200 obtains the position of the room walls, the material (reflectance) of the room walls, the distance between the speaker and the sound collection means 11, the distance between the sound emission means 13 and the listener, and the distance between the speaker and the listener. The heard sound acquisition device 200 generates a transfer function H from the speaking position to the listening position based on the distance between the speaker and the listener, the positional relationship between the speaker and the wall, the positional relationship between the listener and the wall, and the reflectance of the wall. １ The sound acquisition device 200 calculates a transfer function H from the speaking position to the sound collection section of the microphone 11a based on the distance between the speaker and the sound collection means 11, the positional relationship between the speaker and the wall, the positional relationship between the sound collection means 11 and the wall, and the reflectance of the wall. ２ The audible sound acquisition device 200 calculates a transfer function H from the speaking position to the sound collection means 11 based on the distance between the speaker and the sound collection means 11, the positional relationship between the speaker and the wall, and the reflectance of the wall. ２ Ask for.

[0046] (3) In the above embodiment, the audible sound acquisition device 200 calculates the sound pressure at the listening position. However, the sound pressure may be determined by selecting an appropriate value from a database (matrix, etc.) of measurements taken in advance. Multiple microphones and multiple speakers may be used as long as the matrix is ​​set appropriately.

[0047] (4) As shown in Fig. 11, the listening sound acquisition device 200 may implement AI (artificial intelligence) 250. In the embodiment shown in Fig. 11, each conference participant Mi (i = 1 to N) is made to speak in the loudspeaker system 100. At that time, the sound pressure spm of the monitor sound obtained from the loudspeaker system 100 and the sound pressure sp at the listening position are calculated. ｊ is given to AI250 as training data, and the sound pressure spm of the monitor sound and the sound pressure sp at the listening position are calculated. ｊThen, when the public address system 100 is in full operation, the AI ​​250 calculates the sound pressure sp at the listening position based on the sound pressure sp m of the monitor sound obtained from the public address system 100. ｊ We seek this.

[0048] (5) The information providing unit 203 may be arranged in front of each conference participant Mi (i = 1 to N), for example. In this case, when a conference participant Mi is the speaker, the information providing unit 203 corresponding to that conference participant Mi provides visible information indicating the relationship of the speech sound pressure to the appropriate value.

[0049] (6) When there are a plurality of sound emitting means 13 , the audible sound acquisition device 200 may arrange the information providing unit 203 in association with each sound emitting means 13 .

[0050] (7) In the above embodiment, the audible sound acquisition device 200 determined the relationship of the speech sound pressure to the appropriate value based on the sound pressure at the listening position. However, the relationship may also be determined based on a sound pressure other than the sound pressure at the listening position.

[0051] (8) In the above embodiment, the audible sound acquisition device 200 displays the relationship of the speech sound pressure to the appropriate value in three ranks: insufficient, appropriate, and excessive. However, the audible sound acquisition device 200 may display four or more ranks. Alternatively, the audible sound acquisition device 200 may display the speech sound pressure calculated from the sound pressure at the listening position as a bar graph (displayed as a continuous value) for each listening position.

[0052] (9) The gain of the sound amplification transmission path 10 may be set in advance so that the sound amplification level is appropriate to a certain extent for the basic human speech volume. This allows the sound pressure of the speech required for appropriate sound amplification to be set within a comfortable range for the speaker.

[0053] (10) In the transfer system shown in Fig. 3, when the sound pressure sp1 of the sound reaching the listening position via the direct transfer path 10 satisfies a certain condition (first condition), the audible sound acquisition device 200 may regard the sound pressure sp4 of the speech sound reaching the listener via the loudspeaker transfer path 10 as the sound pressure sp5 at the listener's position. For example, when the sound pressure sp1 is sufficiently small, the audible sound acquisition device 200 may determine that the first condition is met and set the sound pressure sp4 = the sound pressure sp5. For example, when the distance between the conference participant Mi and the conference participant Mj exceeds a predetermined threshold, the audible sound acquisition device 200 may determine that the first condition is met and ignore the sound pressure sp1 and set the sound pressure sp4 = the sound pressure sp5. Furthermore, the audible sound acquisition device 200 may determine that the first condition is met and set the sound pressure sp4 to sp5 when the gain of the sound amplification transmission path 10 is high and the value of the sound pressure sp4 is higher than the sound pressure sp1 by a predetermined value or more. Alternatively, the audible sound acquisition device 200 may determine that the first condition is met and set the sound pressure sp4 to sp5 when there is an acoustic obstacle such as a wall or partition between the position of the talker and the position of the listener. Alternatively, the audible sound acquisition device 200 may determine that the first condition is met and set the sound pressure sp4 to sp5 when it receives a setting from the user not to use the sound pressure sp1 of the talker.

[0054] When the sound pressure sp1 of the sound that reaches the listening position via the direct transmission path 10 does not satisfy the first condition (when the sound pressure sp1 is sufficiently large, when the distance between the conference participant Mi and the conference participant Mj is equal to or less than a predetermined threshold, when the value of the sound pressure sp4 compared to the sound pressure sp1 is less than a predetermined value, when there is no acoustic obstacle such as a wall or partition between the speaker's position and the listener's position, or when the user has set the sound pressure sp1 to be used), the audible sound acquisition device 200 calculates the sound pressure sp5 at the listener's position as sp1 + sp4 based on the acquired sound pressure sp4 and the sound pressure sp1 of the speech sound.

[0055] (11) Fig. 12 is a diagram showing a modified example of visible information. In this example, the audible sound acquisition device 200 provides the speaker with the sound pressure at the listening position as a sound pressure distribution on the display 251. The example of Fig. 12 shows the microphone 11a and the speaker 13a on a schematic diagram of a conference room viewed from above. In addition, in the example of Fig. 12, the audible sound acquisition device 200 displays the sound pressure at the listening surface by varying the color intensity. For example, darker areas indicate higher sound pressure, and lighter areas indicate lower sound pressure. The audible sound acquisition device 200 may display the sound pressure at the listening surface by using different colors. For example, the audible sound acquisition device 200 may display positions with higher sound pressure in red and positions with lower sound pressure in blue.

[0056] While the example of FIG. 12 shows two microphones 11a, the eavesdropping sound acquisition device 200 may display different screens for the first microphone 11a and the second microphone 11a, displaying the sound pressure distribution for each microphone. The eavesdropping sound acquisition device 200 may also use different colors for the sound pressure for each microphone. For example, the eavesdropping sound acquisition device 200 may display the sound pressure distribution for the first microphone 11a with a red density and the sound pressure distribution for the second microphone 11a with a blue density. If there are more microphones (e.g., four), the eavesdropping sound acquisition device 200 may assign colors such as red, blue, green, and light blue to each microphone, and use the shades of each color to represent appropriate values ​​or sound pressure information. This allows users to intuitively understand whether the volume of each of the multiple speakers is being appropriately amplified throughout the venue. The eavesdropping sound acquisition device 200 may also accept a user's selection of a specific microphone and display only the selected specific microphone. For example, when there are four microphones and the selection of the first microphone is accepted, the audible sound acquisition device 200 displays information indicating whether the sound picked up by the first microphone is being amplified appropriately. Alternatively, the number of microphones selected is not limited to one, but may be two, three, or more. Furthermore, the audible sound acquisition device 200 may automatically select the microphone that has received the input with the highest sound pressure.

[0057] This allows the speaker to intuitively grasp at a glance the speech sound pressure reaching the conference room, making it easier to change the speech sound pressure so that the sound reaches the listener at an appropriate sound pressure.

[0058] (12) The visible information may be an indicator such as an LED provided for each speaker. For example, the audible sound acquisition device 200 may make the LED glow blue when the sound pressure is too low. Furthermore, the audible sound acquisition device 200 may make the LED glow red when the sound pressure is too high. Furthermore, the audible sound acquisition device 200 may make the LED glow green when the sound pressure is appropriate. Furthermore, the audible sound acquisition device 200 may change the brightness of the LED depending on the sound pressure. For example, the audible sound acquisition device 200 may make the LED darker when the sound pressure is too low and brighter when the sound pressure is too high.

[0059] (13) The audible sound acquiring device 200 may provide the determination result as audio sensory information. For example, the audible sound acquiring device 200 may provide audio guidance such as "Turn up the volume" when the sound pressure is too low, and audio guidance such as "Turn down the volume" when the sound pressure is too high.

[0060] (14) The audible sound acquiring device 200 may notify the determination result by means of sensory information via vibration. In this case, the audible sound acquiring device 200 includes a vibration device carried by the speaker. The audible sound acquiring device 200 vibrates the vibration device when the sound pressure is too low or too high.

[0061] (15) FIG. 13 is a diagram illustrating a modified example of visual information. In this example, the audio capture device 200 provides the speaker with visual information indicating the relationship of the speech sound to the sound pressure by arranging indicators at multiple locations that change in response to (e.g., proportionally to) the magnitude of the sound pressure. More specifically, in this example, multiple ribbons 70a-70e are arranged in front of the speaker 13a as indicators. The multiple ribbons 70a-70e hang from the ceiling of a conference room, for example. The multiple ribbons 70a-70e each have different colors and physical properties. Physical properties include, for example, elastic modulus (hardness) or weight. The ribbon 70a has the lightest color and is the softest (or lightest). The ribbon 70e has the darkest color and is the hardest (or heaviest). Therefore, the ribbon 70a is the most mobile. The ribbon 70a moves even when the sound pressure of the speaker 13a is low. The ribbon 70e moves least. The ribbon 70e moves when the sound pressure of the speaker 13a is high. In other words, the higher the sound pressure of the speaker 13a, the more the ribbons 70a to 70e move in sequence. This allows the speaker to visually recognize the sound pressure by watching the movement of the ribbons 70a to 70e. For example, if the ribbon 70e moves, the speaker can determine that the sound pressure is excessive. Also, if only the ribbon 70a moves, the speaker can determine that the sound pressure is insufficient.

[0062] Fig. 15 is a diagram showing another modified example of visual information. In the example of Fig. 15, a ribbon 70g, only a portion of which moves in response to a sound pressure above a predetermined value (e.g., 70 dB or higher), is placed in front of the speaker 13a. A lower portion of the ribbon 70g is made of a material with a low elastic modulus or a light weight. A portion of the ribbon 70g above a predetermined position is made of a material with a high elastic modulus or a heavy weight. When the sound pressure reaches an appropriate value, only the lower portion of the ribbon 70g moves. This allows the speaker to visually recognize that the sound pressure has reached an appropriate value by watching the movement of the ribbon 70g.

[0063] FIG. 16 is a diagram showing another modified example of the visual information. The ribbon 70h shown in the example of FIG. 16 has a higher elastic modulus (or heavier weight) the closer it is to the ceiling, and a lower elastic modulus (or lighter weight) the further it is from the ceiling. In other words, when the sound pressure of the speaker 13a is low, the lower part of the ribbon 70h moves, and as the sound pressure increases, the upper part also moves. In this case, too, the speaker can visually recognize the sound pressure by watching the movement of the ribbon 70h. For example, if the entire ribbon 70h moves, the speaker can determine that the sound pressure is excessive. Also, if only the lower part of the ribbon 70h moves, the speaker can determine that the sound pressure is insufficient.

[0064] FIG. 17 is a diagram showing a further modified example of the visible information. The ribbon 70i shown in the example of FIG. 17 is thin-film-shaped and made of a lightweight material with a low overall elastic modulus. Therefore, the ribbon 70i vibrates as a whole even at low sound pressure. The ribbon 70i also has a patterned design formed on its main surface. When the ribbon 70i vibrates, the patterned design sways. The speaker can visually determine the level of sound pressure by looking at the swaying of the patterned design of the ribbon 70i. For example, if the design of the ribbon 70i sways violently, the speaker can determine that the sound pressure is excessive. If the swaying of the design of the ribbon 70i is small, the speaker can determine that the sound pressure is insufficient.

[0065] (16) The audible sound acquisition device 200 may determine the sound pressure at any position on the transmission path from the level of the sound signal supplied to the speaker. Alternatively, the audible sound acquisition device 200 may determine the sound pressure at any position on the transmission path from the drive voltage of the speaker.

[0066] (17) The visible information may indicate the proportion of the portion of the room where the sound pressure is appropriate relative to the entire room. For example, when the proportion of the portion of the room where the sound pressure is appropriate relative to the entire room is a predetermined value (e.g., 70%), the audible sound acquisition device 200 may display the fact that the sound pressure is appropriate using a display such as an LED, LCD, or OLED.

[0067] (18) "Suitability" is not limited to the case where sound pressure is appropriate. "Suitability" may also refer to whether frequency characteristics are appropriate. "Suitability" may also refer to whether the sound pressure of speech is appropriate relative to the sound pressure of noise. "Suitability" may also be a judgment result based on an index (STI: Speech Transmission Index) that evaluates the clarity of speech. Speech becomes difficult to hear when the original waveform is distorted by reverberation, noise, etc. during the transmission process. STI is an index that evaluates the clarity of speech based on how faithfully the speech is transmitted without such waveform distortion. In this embodiment, a transfer function H1 from the speaker to the listener, a transfer function H2 from the speaker to the microphone 11a, a total gain G of the microphone 11a, the amplifier 12a, and the speaker 13a, and a transfer function H from the speaker 13a to the listening position are calculated by simulation or measurement, etc. ３ is required. As described above, the transfer function including the loudspeaker system is expressed as H1 + (H2 + H3) * G. This transfer function can be expressed as a time-domain impulse response IR. The listening sound acquisition device 200 measures noise N, such as air conditioning noise, in advance or during periods of quiet speech. The sound pressure sp5 at the listening position is calculated using the above formula (3) or (6). Therefore, the SNR of speech and noise is calculated as sp5 / N. The STI is calculated based on the impulse response IR and the SNR in accordance with IEC 60268-16. The listening sound acquisition device 200 may display the calculated STI instead of the sound pressure. Standards for the STI have been established, such as an STI of 0.75 or higher being Excellent and a SNR of 0.6 to 0.75 being Good. Therefore, the audible sound acquisition device 200 may display the STI value, or may display Excellent, Good, or the like according to this standard.

[0068] (19) Fig. 14 is a schematic side view of a conference room. The audible sound acquisition device 200 in this example emits light according to the directional angle of the sound emitted by the sound emission means, and the light provides the speaker with visual information about the sound emission area.

[0069] In the example of Figure 14, each speaker installed on the ceiling is provided with a light emitter that emits light according to the directivity angle of the sound. The area where the sound from multiple speakers reaches is brightened by the light from multiple light emitters. Furthermore, if there is a step in the ceiling or a partition in the space, the light from the light emitters will be blocked.

[0070] Because light and sound have different diffraction conditions and attenuation rates, the ranges in which light and sound can easily reach and the ranges in which they cannot easily reach cannot be said to be exactly the same. However, as a general trend, it can be interpreted that areas where light can easily reach are also areas where sound can easily reach. Therefore, speakers can visually and intuitively understand that loud sounds can reach bright places and that sound cannot easily reach dark places.

[0071] 100... Public address system, 10... Public address transmission path, 11... Sound collection means, 12... Amplification means, 13... Sound emission means, 11a... Microphone, 12a... Amplifier, 13a... Speaker, 20... Direct transmission circuit, 200... Hearing sound acquisition device, 201... Control unit, 202... Measurement unit, 203... Information provision unit, M ｉ , M ｊ ...Conference participants

Claims

1. A method for acquiring audible sounds in a public address system that delivers a speaker's speech to a listener via a public address transmission path including a sound collection means, an amplification means, and a sound emission means, the method comprising: acquiring sound pressure at an arbitrary position on the transmission path of the speech sound; and determining the sound pressure at the listener's listening position based on the acquired sound pressure.

2. The method for acquiring heard sounds described in claim 1, wherein, when a speech sound reaching the listener via a direct transmission path not including the loudspeaker transmission path satisfies a first condition, the sound pressure of the speech sound reaching the listener via the loudspeaker transmission path is regarded as the sound pressure at the listener's position, and the sound pressure at the listener's listening position is calculated.

3. The method for acquiring heard sounds according to claim 1 or 2, further comprising measuring the sound pressure at an arbitrary position on the transmission path of the speech sound, and determining the sound pressure at the listening position of the listener by a calculation based on the measured sound pressure.

4. A method for acquiring sound as claimed in claim 1 or 2, further comprising measuring the sound pressure of the input sound to the sound collection means and determining the sound pressure at the listening position by a calculation based on the measured sound pressure.

5. A method for acquiring sound as claimed in claim 1 or 2, wherein the sound pressure of the output sound of the sound emitting means is measured, and the sound pressure at the listening position is determined by a calculation based on the measured sound pressure.

6. A method for acquiring sound as claimed in claim 1 or 2, in which the sound pressure of the input sound to the sound collection means and the sound pressure of the output sound from the sound emission means are measured, and the sound pressure at the listening position is determined by a calculation based on the measured sound pressures.

7. A method for acquiring heard sounds according to claim 1 or 2, wherein the sound pressure of the speech sound is measured, and the sound pressure at the listening position is determined by a calculation based on the measured sound pressure.

8. A method for acquiring audible sounds according to claim 1 or 2, further comprising the steps of: determining a relationship between the sound pressure of the speech sound and an appropriate value; and providing the speaker with visible information indicating the determination result.

9. A method for acquiring audible sounds according to claim 1 or 2, further comprising the steps of: determining a relationship between the sound pressure of the speech sound and an appropriate value; and providing the speaker with sensory information indicating the result of the determination.

10. The method for acquiring heard sounds according to claim 8, further comprising determining a relationship of the sound pressure of the speech sound to an appropriate value based on the sound pressure at the listening position.

11. The method for acquiring audible sounds according to claim 8, wherein a device for providing said visual information is arranged in correspondence with said sound emitting means.

12. The method for acquiring heard sounds according to claim 1 or 2, wherein the sound pressure at the listening position is provided to the speaker as a sound pressure distribution.

13. A method for acquiring audible sounds as described in claim 1 or claim 2, in which light is emitted according to a directional angle of the sound emitted by the sound emission means, and the sound emission area of ​​the sound is provided to the speaker as visible information by the light.

14. A method for acquiring audible sounds as described in claim 1 or 2, in which indicators that change in response to the magnitude of the sound pressure are arranged in multiple locations, thereby providing the speaker with visual information indicating the relationship of the sound pressure of the speech sound to an appropriate value.

15. A method for acquiring sound heard as described in claim 2, comprising the steps of: detecting the head positions of the speaker and the listener; acquiring a transfer function from the speaker to the listener's position via the direct transfer path based on the head positions; acquiring a transfer function from the speaker to the sound collection means; and acquiring a transfer function from the sound emission means to the listener's position based on these acquired transfer functions.

16. A sound acquisition device for acquiring sound pressure at a listening position of a listener in a public address system that delivers a speaker's speech to a listener via a public address transmission path including a sound collection means, an amplification means, and a sound emission means, the sound acquisition device having a control unit that acquires sound pressure at an arbitrary position on the transmission path of the speech sound, and determines the sound pressure at the listening position of the listener based on the acquired sound pressure.

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