JP7605658B2 - Meeting support system - Google Patents

Description

The present invention relates to a conference support system that can transmit the voices of conference participants clearly to only them in a meeting space, etc., without leaking the conversations of conference participants to nearby people, even if the conference participants are wearing masks or transparent partitions are installed on the conference desk.

In today's workplaces, spaces for meetings and discussions (meeting spaces) are often located close to spaces where individuals work (work spaces).

In addition, in order to encourage collaboration, the installation of open desks and the introduction of free addresses are being promoted, which make it easier for workers to come into contact with each other and have conversations. Here, an open desk is a large desk that can seat several people, and is a space that each worker can use freely to carry out their work or tasks.

For example, Patent Document 1 (JP Patent Publication 2010-4962 A) discloses a furniture system that is primarily comprised of large free-address desks that can be used by multiple workers facing each other.

Additionally, workplaces are often planned with a mix of different spaces to make it easier to transition from individual work to conversations and meetings.

However, in a workplace with a mixture of such diverse spaces, there is an issue that conversations in meeting spaces or open desks can be heard by other workers nearby, reducing their productivity.

Therefore, the inventor proposed a conference support system in the application of Patent Document 2 (Japanese Patent Application No. 2020-86764) that collects the voices of conference participants, plays the collected voices on a speaker, and presents them to the conference participants to support the conference, in which a parabolic surface is provided on a part of the ceiling, and the sound played on the speaker is reflected by the parabolic surface. In addition, in the application, a loop such as microphone → amplifier → speaker (→ parabolic ceiling surface) → microphone exists, and howling suppression measures are necessary, so a method for suppressing howling by an electroacoustic device was proposed in the second embodiment of the application.
JP 2010-4962 A Patent application No. 2020-86764

Currently, with the outbreak of the novel coronavirus (COVID-19) pandemic, measures to prevent infection have become commonplace, such as wearing masks during meetings and installing transparent partitions such as acrylic panels in meeting spaces. However, this has resulted in problems such as not being able to clearly hear conversations.

When meeting participants wear masks or transparent partitions are installed at meeting desks, it becomes more difficult to transmit sound. However, the above application does not specify the frequency characteristics of the speakers and other devices used to play back sound, and there is no description of how to amplify and play back sound recorded by a microphone and transmit it to the speaker and meeting participants.

In addition, although the application proposed measures to suppress feedback, at present, even if feedback is suppressed using the electroacoustic device, the effect is insufficient, and the amplification rate of the sound reproduced from the speaker cannot be increased, resulting in an insufficient volume of the conversation sound transmitted to the speaker and conference participants.

The present invention solves the above problems, and the conference support system according to the present invention supports a conference by collecting speech by conference participants, playing the collected speech on a speaker, and presenting it to the conference participants. The conference support system includes a microphone that converts an input audio signal into an electrical signal, a first filter that passes only electrical signals corresponding to components of a first frequency or higher from the electrical signals converted by the microphone, a second filter that passes only electrical signals corresponding to components of a second frequency or higher from the electrical signals converted by the microphone, a setting unit that sets either the first filter or the second filter, an amplifier that amplifies the electrical signal that has passed through the filter set by the setting unit, a speaker that plays the electrical signal amplified by the amplifier, and a parabolic surface formed on a part of the ceiling that reflects the sound played by the speaker.

The conference support system according to the present invention supports a conference by collecting speech from conference participants, playing the collected speech on a speaker, and presenting it to the conference participants. The conference support system includes a microphone that converts an input audio signal into an electrical signal, an amplifier that amplifies the electrical signal converted by the microphone, a first tweeter that reproduces only an electrical signal that corresponds to a component of a first frequency or higher from the electrical signal amplified by the amplifier, a second tweeter that reproduces only an electrical signal that corresponds to a component of a second frequency or higher from the electrical signal amplified by the amplifier, a setting unit that sets either the first tweeter or the second tweeter, and a parabolic surface formed on a part of the ceiling that reflects the sound reproduced by the tweeter set by the setting unit.

The conference support system according to the present invention supports a conference by collecting speech from conference participants and playing the collected speech on a speaker to present to the conference participants, and is characterized in having a microphone that converts an input audio signal into an electrical signal, an equalizer that adjusts the amount of amplification for each frequency band of the electrical signal converted by the microphone, a setting unit that sets the equalizer to either increase the amount of amplification of a frequency band equal to or higher than a first frequency, or increase the amount of amplification of a frequency band equal to or higher than a second frequency, an amplifier that amplifies the electrical signal that has passed through the equalizer, a speaker that plays the electrical signal amplified by the amplifier, and a parabolic surface formed on a part of the ceiling that reflects the sound played by the speaker.

The conference support system according to the present invention is also characterized in that the first frequency is 1 kHz.

The conference support system according to the present invention is also characterized in that the second frequency is the lower limit frequency of a 1/3 octave band with a center frequency of 2.5 kHz.

The conference support system according to the present invention is also characterized in that a soundproof panel is disposed below the speaker.

The conference support system according to the present invention uses a filter to emphasize consonants when playing back, so that voices can be transmitted clearly to conference participants even if they are wearing masks. Furthermore, the conference support system according to the present invention uses a setting unit to set either a first filter that is suitable when a partition is installed, or a second filter that is suitable when a partition is not installed. Therefore, with this conference support system according to the present invention, voices can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

In addition, the conference support system according to the present invention allows either the first tweeter or the second tweeter to be set by the setting unit depending on the installation status of the partition, so that voice can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

In addition, the conference support system according to the present invention has a setting unit that appropriately adjusts the amount of amplification for each frequency band in the equalizer depending on the installation status of the partition, so that voice can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

In addition, the conference support system according to the present invention makes it possible to increase the amplification rate of the sound reproduced from the speaker by using the above-mentioned filter, thereby sufficiently increasing the volume of the conversation sound transmitted to the speaker and conference participants.

In addition, the conference support system according to the present invention makes it possible to increase the amplification rate of the sound reproduced from the speaker by using the above-mentioned filter, thereby sufficiently increasing the volume of the conversation sound transmitted to the speaker and conference participants.

1 is a diagram illustrating an overview of a conference support system 1 according to an embodiment of the present invention. 2 is a block diagram of an audio processing unit 40 of the conference support system 1 according to the embodiment of the present invention. 11 is a diagram showing frequency dependence of sound attenuation when sound is diffracted at the end of the partition 100. FIG. 1 is a diagram illustrating the geometric arrangement of a speaker 60 and a ceiling in the conference support system 1. FIG. 1 is a diagram illustrating sound reflected by a parabolic ceiling portion 17 of the conference support system 1. FIG. FIG. 1 is a block diagram of a conference support system 1 according to a second embodiment of the present invention. FIG. 11 is a block diagram of a conference support system 1 according to a third embodiment of the present invention. FIG. 13 is a diagram illustrating an overview of a conference support system 1 according to a fourth embodiment of the present invention. 11 is a diagram illustrating a case where a sound reflecting object is placed within the sound presentation range. FIG. FIG. 13 is a diagram illustrating an overview of a conference support system 1 according to a fifth embodiment of the present invention. 11 is a diagram for explaining the difference in propagation path based on the height of the focal point F and the height of the sound-proof plate 70. FIG. 1 is a schematic diagram of sound propagation paths when the upper surface of a sound-proofing plate 70 is flat and parallel to a floor surface 20. FIG. FIG. 1 is a diagram illustrating a problem caused by a small speaker 60 aligned at a focal point F. 13A to 13C are diagrams illustrating the effects of the conference support system 1 according to the fifth embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings. The conference support system 1 according to the present invention is expected to be applied to a meeting space located near, for example, a large desk in a free address style where work is carried out, or an open desk.

In addition, it is expected that workers will work at the large desks and open desks in the free address style mentioned above, while meetings will take place in meeting spaces where meeting participants can speak.

In this specification, a "worker" is defined as a person who does desk work, such as paperwork and computer input, and generally does not speak, and is distinguished from a meeting participant who takes part in a meeting in a meeting space and speaks.

The conference support system 1 according to the present invention aims to present appropriate audio to conference participants while preventing the content of conversations between participants in the meeting space from being heard by other workers at nearby large desks or open desks as much as possible. To achieve this, the conference support system 1 according to the present invention collects the speech of conference participants (speakers) and plays the collected speech on a speaker to present it to the conference participants, thereby supporting the conference.

In the conference support system 1 according to the present invention, attention is paid to the characteristics of voice and hearing, as well as the characteristics of voice attenuation caused by masks and partitions, and the frequency characteristics of the voice played from the speaker 60 are specified, thereby enabling voice to be transmitted clearly to conference participants.

Speech is composed of vowels and consonants, the former consisting mainly of low frequency components and the latter of high frequency components. It is known that in the sense of hearing, low frequency components mask high frequency components, and this masking is also at work when we perceive speech. This type of masking is one of the causes of poor speech audibility.

In the conference support system 1 according to the present invention, when the collected speech of a speaker is played back to the conference participants through a speaker, the frequency of the sound played back from the speaker is specified by focusing on the characteristics of the sound and hearing, thereby preventing a decrease in clarity of the played back sound and solving the problem.

Figure 1 is a diagram for explaining an overview of a conference support system 1 according to an embodiment of the present invention. It shows a situation in which a conference is being held with two participants at a desk 25 placed on a floor surface 20. It is assumed that workers are working near this desk 25 at the aforementioned large free address type desk or open desk (neither of which are shown).

It is assumed that conference participants will wear masks 110 as a measure against infectious diseases. In addition to the infection control measures using masks 110, in some cases partitions 100 are installed on desks 25 to separate conference participants from each other. Note that such partitions 100 may or may not be installed, but the manner in which sound is propagated differs significantly depending on whether or not a partition 100 is installed. Therefore, in the conference support system 1 according to the present invention, the system settings are changed depending on whether the partition is installed or not.

In the following, this embodiment will be described on the assumption that a partition 100 is provided on the desk 25. Also, in this embodiment, an example will be described in which one partition 100 is provided between two conference participants, separating them into two spaces, but the number of partitions provided and the number of spaces separated by the partitions are not limited to this. Also, as a method of installing microphones, a microphone may be provided for each space separated by a partition to collect the voices of the conference participants in each space, or a microphone may be suspended below the speaker 60 to collect the voices of the conference participants.

In this embodiment, microphones 30, 30' are installed in each space above the desk 25, and these microphones 30, 30' pick up the voices of each conference participant. When a voice signal is input from the voice, the microphones 30, 30' convert it into an electrical signal.

The electrical signals converted by each of the microphones 30, 30' are input to the audio processing unit 40. In this audio processing unit 40, the electrical signals are converted into signals suitable for playback by the speaker 60. FIG. 2 is a block diagram of the audio processing unit 40 of the conference support system 1 according to an embodiment of the present invention. The audio processing unit 40 in FIG. 2 is one example, and various other aspects are possible. In the subsequent stage of the audio processing unit 40 in FIG. 2, the level of the electrical signal is adjusted by the volume adjustment unit 41, and the electrical signal is amplified by the amplifier 50.

In FIG. 2, the electrical signals converted by the microphones 30 and 30' are input to either the first filter 47 or the second filter 48 in the audio processing unit 40.

The first filter 47 is a high-pass filter that passes only electrical signals corresponding to components equal to or greater than a first frequency (1 kHz) among the electrical signals converted by the microphones 30, 30'. The second filter 48 is a high-pass filter that passes only electrical signals corresponding to components equal to or greater than a second frequency (the lower limit frequency (approximately 2.23 kHz) of the 1/3 octave band with a center frequency of 2.5 kHz) among the electrical signals converted by the microphones 30, 30'.

The setting unit 35 sets whether the electrical signal from the microphones 30 and 30' is to pass through the first filter 47 or the second filter 48.

When passing the electrical signals from the microphones 30, 30' through the first filter 47, the setting unit 35 turns on the first switch 37 and turns off the second switch 38. When a partition 100 is provided on the desk 25, the setting is made to pass the electrical signals from the microphones 30, 30' through the first filter 47.

When passing the electrical signals from the microphones 30, 30' through the second filter 48, the setting unit 35 turns off the first switch 37 and turns on the second switch 38. When the partition 100 is not provided on the desk 25, the setting is made to pass the electrical signals from the microphones 30, 30' through the second filter 48.

The setting in the setting unit 35 may be performed manually by a person determining whether or not the partition 100 is present on the desk 25, or it may be performed automatically, for example, by acquiring an image of the desk 25 and determining whether or not the partition 100 is present on the desk 25 through image analysis or the like.

The reason why the setting unit 35 selectively sets either the first filter 47, which passes only electrical signals corresponding to components equal to or greater than the first frequency (1 kHz), or the second filter 48, which passes only electrical signals corresponding to components equal to or greater than the second frequency (the lower limit frequency of a 1/3 octave band with a center frequency of 2.5 kHz) will now be described.

The majority of Japanese syllables are composed of consonants and vowels, each of which has different frequency characteristics. According to Reference 1, consonants have components mainly in the high frequency range (1k to 6kHz) compared to vowels. And according to Reference 2, consonants are said to play an important role in communicating speech clearly in Japanese.

Meanwhile, according to Reference 3, when a speaker wears a commonly used nonwoven or cloth mask, there is significant attenuation of voice components contained in the 1/3 octave band with a center frequency of 2.5 kHz or the 1/3 octave band with a center frequency of 3.15 kHz or higher. The main components of consonants, which play an important role in the clarity of conversation, are contained in these bands, and attenuation of these bands makes it impossible to clearly transmit conversational voices.

In addition, when partition 100 is placed between the speaker and the other conference participants, the propagation path of the sound that would have traveled directly from the speaker to the conference participants if partition 100 were not present is now composed of a path that diffracts at the end of partition 100, and a path that enters the speaker's side of partition 100, passes through partition 100, and is re-emitted from the opposite side.

In the path where sound diffracts through the edge of the partition 100, the sound is attenuated due to the diffraction effect, but the amount of attenuation is generally greater the higher the frequency. Also, in the path where sound penetrates the partition 100, sound is attenuated as it penetrates the partition 100, which is made of a plate or film material, but the amount of attenuation is generally greater the higher the frequency.

Therefore, when partition 100 is placed between the speaker and the other conference participants, the high frequency components of the voice are attenuated more than when partition 100 is not present. As mentioned above, the main components of consonants are in the high frequency range (1 kHz to 6 kHz) compared to vowels, and attenuation of this range makes it difficult to clearly transmit conversational voices.

3 shows an example of the results of predicting the amount of sound attenuation when sound is diffracted at the end of the partition 100 using the calculation formula shown in Reference 4. The values on the vertical axis indicate the amount of sound attenuation based on the case where there is no partition. The prediction conditions are as follows:
- The distance between the speaker and other conference participants should be 2m, and their heads should be at the same height.
The partition 100 is set in the middle between the two people, and its width extends 0.75 m on each side in a direction perpendicular to the line connecting the two people. The height is set to 1 m above the head position of both people.
The sound propagation path is assumed to be a path that diffracts at the top and both side edges of the partition 100. In other words, the bottom edge of the partition 100 is in contact with the desk 25, and sound does not propagate along the path that diffracts at the bottom edge. The calculation result is a combination of the calculation results for each path.
The path of sound transmitted through the partition 100 is not taken into consideration here. For example, if it is assumed that the partition 100 is made of a 4 mm thick acrylic plate, which is thick enough to be self-supporting, then at frequencies of 500 Hz or higher under the above conditions, the sound transmitted through the partition 100 is sufficiently small compared to the sound diffracted at the end of the partition 100.

Figure 3 shows that diffraction causes an attenuation of more than 13 dB at 1 kHz, and the degree of attenuation increases as the frequency increases. As mentioned above, the path through the partition 100 is not considered here, but the trend remains the same even if this is taken into account.

In view of the above, the conference support system 1 according to the present invention is a system that amplifies and plays back the speaker's voice to clearly transmit the conversational voice to other conference participants, but does not amplify all frequency components of the voice. Instead, it amplifies and plays back the voice by emphasizing only the above-mentioned playback frequency band, which plays an important role in the clarity of the voice transmission and contains many consonant components that are easily attenuated by the mask 110 or partition 100.

Therefore, when a partition 100 is installed, the playback frequency band is set to 1 kHz or more, and in the conference support system 1 according to the present invention, the first filter 47 cuts out frequencies below the first frequency (1 kHz) and reproduces the sound through the speaker 60. This has the advantage of efficiently improving the clarity of conversational sounds and suppressing the occurrence of howling, compared to when all frequency components of the sound are amplified.

From the viewpoint of suppressing feedback, it is desirable for the playback frequency band to be as narrow as possible, so under conditions where only the mask 110 is worn and the partition 100 is not installed, the playback frequency band is set to be equal to or higher than the lower limit frequency (approximately 2.23 kHz) of the 1/3 octave band with a center frequency of 2.5 kHz, based on the results shown in Reference 3. In other words, in the conference support system 1 according to the present invention, when the partition 100 is not present, the second filter 48 cuts off frequencies below the second frequency (the lower limit frequency (approximately 2.23 kHz) of the 1/3 octave band with a center frequency of 2.5 kHz).

Similarly, according to Reference 1, the frequency band containing the main components of consonants is 1 kHz to 6 kHz. Therefore, the reproduction frequency band of the speaker 60 may be set to be equal to or higher than the lower limit frequency (or 1 kHz) of the 1/3 octave band with a center frequency of 2.5 kHz and equal to or lower than 6 kHz. In other words, instead of the second filter 48, which is a high-pass filter, it is also possible to use a band-pass filter with a pass band of 1 kHz to 6 kHz.

In the present invention, the playback frequency band is basically 1 kHz or higher, and also includes a band of 6 kHz or higher. The reason for this is that, although weaker than the band between 1 kHz and 6 kHz, the band of 6 kHz or higher also contains consonant components. Also, even if the energy of consonants is minute, they affect the clarity of speech (Reference 2), so the playback frequency band includes 6 kHz or higher, even though it does not contain the main components.

The amount of attenuation of conversational voices by the mask 110 is shown in, for example, Reference 3. Furthermore, if the material and dimensions constituting the partition 100 and the installation conditions are known, the amount of attenuation of voice in the path diffracted at the end of the partition 100 and the path passing through the partition 100 can be predicted for each frequency using known formulas and charts. In this case, if a device capable of adjusting the amount of amplification for each frequency band, such as a graphic equalizer, is used as the device constituting the present invention, it is effective to set the amount of amplification for each frequency band belonging to the playback frequency band to be equal to or greater than the above-mentioned amount of attenuation.

Returning to FIG. 2, the output from either the first filter 47 or the second filter 48 is input to the volume adjustment unit 41. The volume adjustment unit 41 adjusts the volume of the sound reproduced by the speaker 60. This volume adjustment unit 41 may be operated automatically or manually. In the latter case, it is preferable that components such as an input knob or input slider for adjusting the volume are appropriately provided on the desk 25.

The electrical signal amplified by the amplifier 50 of the audio processing unit 40 is input to the speaker 60, which reproduces the sound. The speaker 60 is installed so that its directivity faces upward, and the sound is emitted from the speaker 60 towards the ceiling 10.

The ceiling 10 has a general ceiling portion 15 having a horizontal surface, and a parabolic ceiling portion 17 having a concave parabolic surface formed as part of the general ceiling portion 15. In the conference support system 1 according to the present invention, the layout is such that the parabolic ceiling portion 17 is disposed above the desk 25. In addition, it is preferable that the size of the parabolic ceiling portion 17 is large enough in plan view to at least include the conference participants seated around the desk 25.

In this embodiment, the parabolic ceiling portion 17 is provided as part of the ceiling 10, but a structure equivalent to the parabolic ceiling portion 17 may be provided separately from the ceiling 10. For example, a parasol-like structure equivalent to the parabolic ceiling portion 17, independent of the general ceiling portion 15 in the ceiling 10, may be provided on the ceiling 10.

The parabolic ceiling portion 17 as described above reflects the sound reproduced by the speaker 60 vertically downward. In the conference support system 1 according to the present invention, the ceiling structure is devised so that sound is presented to a limited area (the meeting space where the desks 25 are arranged) even when using ordinary speakers. Figure 4 is a diagram explaining the geometric arrangement of the speaker 60 and the ceiling in the conference support system 1, and is a schematic diagram showing a cross section of the ceiling 10 and floor surface 20 of a building.

The ceiling 10 is composed of a general ceiling portion 15 that is parallel to a general floor surface 20, and a parabolic ceiling portion 17 that is formed on part of the ceiling 10. Here, the x-axis is the horizontal direction, the y-axis is the vertical direction, and coordinates (x, y) are defined with the position F of the speaker 60 (not shown in FIG. 4) as the origin.

In the coordinate system defined above, the parabolic ceiling portion 17 is configured to overlap with the surface of a body of revolution obtained by rotating y= ^-x2 /4L+L around the y axis. In this case, the origin (0,0) of the xy coordinate system coincides with the focal point F of the parabolic ceiling portion 17.

If the directional range of the speaker 60 (not shown in FIG. 1) is φ, it is preferable that the cone defined by φ is contained within the parabolic ceiling portion 17.

The playback sound presentation means in the conference support system 1 according to the present invention is composed of a parabolic ceiling portion 17 having a shape that forms part of a paraboloid as described above, and a speaker 60 installed below the parabolic ceiling portion 17 with its direction facing upward. The speaker 60 is also installed so as to be located at the focal point F of the paraboloid of the ceiling 10.

In the above-mentioned relationship, when the speaker 60 is placed at F, as shown in Figure 5, the sound reflected by the parabolic ceiling portion 17 travels vertically downward toward the floor surface 20.

In the conference support system 1 according to the present invention, it is preferable that the range in which the ceiling surface forms a paraboloid is the range in which the sound emitted from the speaker 60 is incident, i.e., the range that can cover the directional range of the speaker 60.

Sound emitted from speaker 60 installed at the focus F of the paraboloid that constitutes parabolic ceiling portion 17 enters parabolic ceiling portion 17, which forms part of the paraboloid, and then reflects vertically downward toward desks 25 around which the conference participants are seated. In the conference support system 1 according to the present invention, the sound emitted from the speaker can be kept within the desired range of presentation without using expensive speaker systems such as parametric speakers or flat panel speakers. In this way, the conference support system 1 according to the present invention can be realized inexpensively using general speakers.

The mechanism for supporting audio transmission using the parabolic ceiling portion 17 and the speaker 60 has already been proposed by the inventors in Japanese Patent Application No. 2017-160105 (see Japanese Patent Application Laid-Open No. 2019-39166). This proposal had the effect of providing sound information such as background music and announcements to only a limited area in art galleries and museums.

On the other hand, in the conference support system 1 according to the present invention, it can be considered that conference participants can objectively judge their own voice volume by listening to their own voice reproduced by the speaker 60 and reflected by the parabolic ceiling portion 17. Therefore, conference participants can control and suppress their own voice volume. This makes it possible for the conference support system 1 to suppress conversations at a volume that can be heard by workers nearby the meeting space. This effect is not necessarily easily derived from the previous proposal.

Now, if the parabolic ceiling portion 17 is wider than the main directional range of the speaker 60, the sound reproduced from the speaker 60 will not propagate to the surroundings, but will be presented only directly below the parabolic ceiling portion 17.

In this way, if the directional range of the parabolic ceiling portion 17 and the speaker 60 is appropriately set to cover the meeting space, the sound recorded by the microphones 30, 30' is reliably transmitted only to the meeting participants who are conversing in the meeting space.

The feature of the voice transmission support provided by the conference support system 1 according to the present invention is that the speaker's own conversation voice is amplified and transmitted not only to the person in the conversation but also to the speaker himself at the same time.

By using the conference support system 1 according to the present invention, the speaker can feel that their voice sounds loud and that their voice is being reliably transmitted to the person they are speaking with, so it is expected that they will naturally adjust their voice volume to be lower. In this way, if the speaker's voice volume is suppressed, the amount of conversation sound propagating from the meeting space to the surrounding area is reduced, reducing the decrease in the work efficiency of other nearby workers and the degree of interference with other conversations.

In this way, sound can be reliably transmitted to conference participants who are conversing only in the meeting space covered by the parabolic ceiling section 17, while guiding the speaker to reduce the volume of their voice. As a result, it is possible to reduce the decrease in the work efficiency of other nearby workers and the degree of interference with other conversations.

The microphones 30, 30' used in the conference support system 1 according to the present invention are preferably installed on the desk 25. However, it is also possible to use lapel microphones worn by each of the conference participants who will be having a conversation.

The conference support system 1 according to the present invention, configured as described above, can prevent conversations in a meeting space from being heard by other nearby workers, thereby preventing a decrease in the productivity of those other workers, without the need to take measures such as surrounding the meeting space with a partition.

The conference support system 1 according to the present invention uses either the first filter 47 or the second filter 48 to emphasize consonants when playing back, so that voices can be transmitted clearly to conference participants even if they are wearing masks. Furthermore, in the conference support system 1 according to the present invention, the setting unit sets either the first filter, which is suitable when the partition 100 is installed, or the second filter, which is suitable when the partition 100 is not installed. Therefore, with this conference support system according to the present invention, voices can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

In addition, according to the conference support system 1 of the present invention, by providing a high-pass filter as described above, it is possible to increase the amplification rate of the sound reproduced from the speaker 60, and the volume of the conversation sound transmitted to the speaker and conference participants can be sufficiently increased.

In other words, the effect of making conversational voices clearer by playing back based on the playback frequency band, and thus being able to properly transmit voice to conference participants, can be achieved without increasing the amplification rate of the playback voice. In other words, even with an amplification rate that does not cause feedback, voices can be properly transmitted to conference participants.

In addition, according to the conference support system 1 of the present invention, when the howling frequency is outside the playback frequency band, it is possible to sufficiently increase the amplification rate, which also improves the audio transmission to conference participants.

In addition, the conference support system 1 according to the present invention can guide speakers to reduce their speaking volume while reliably transmitting sound only to conference participants within the range covered by the parabolic surface on the ceiling.

In addition, it is possible to effectively provide feedback to the speaker of their own voice, which in turn can more effectively encourage the speaker to reduce the volume of their voice. This also reduces the degree to which conversation sounds leak into nearby spaces.

This makes it possible to reduce the amount of conversation sound that propagates to adjacent spaces. As a result, it is possible to reduce the degree of decline in the work efficiency of other workers working in adjacent spaces, reduce the degree of interference with other conversations taking place in adjacent spaces, and reduce the feeling of noise throughout the workplace.

In addition, the conference support system 1 according to the present invention makes it possible to prevent highly confidential conversations from being leaked to those around when they are held in a meeting space.

The above-mentioned effects can be obtained without increasing the amplification rate of the sound reproduced by the speaker 60. In other words, the degree to which the reproduced sound leaks to the surroundings can be suppressed, and the above-mentioned effects can be obtained even with an amplification rate that does not cause howling. On the other hand, if the howling frequency is outside the reproduction frequency band, it is possible to sufficiently increase the amplification rate.

Even if the feedback frequency is within the playback frequency band, the diffraction effect of the shielding plate and the sound absorption effect of the sound absorbing material are high in the high frequency range, so by combining physical methods such as the shielding plate described in Patent Document 2, feedback can be effectively suppressed and the amplification rate can be sufficiently increased.

In addition, in the conference support system 1 according to the present invention, if a microphone installed on a desk is used, there is no need for a wearable device such as an intercom, and the above-mentioned effects can be obtained without compromising convenience. Wearing an intercom or the like not only reduces convenience, but can also lead to a decrease in meeting efficiency due to discomfort for workers who are not accustomed to it.

In addition, in the conference support system 1 according to the present invention, the speaker installed at the focal point F can be a general speaker, and the above-mentioned effects can be achieved at low cost. Parametric speakers and flat panel speakers exist as speaker systems with narrow directional characteristics for playing back conversation sounds in a limited range, but they have issues with cost and sound quality.

The conference support system 1 according to the present invention is also effective when conversing with people in remote locations, such as via a web conference, as well as when actually conversing face-to-face.

Next, another embodiment of the present invention will be described. In the previous embodiment, the high-pass filter of either the first filter 47 or the second filter 48 passes only the electrical signals output from the microphones 30, 30' that correspond to components of a predetermined frequency or higher, and reproduces the signals from the speaker 60.

On the other hand, in the second embodiment, such a high-pass filter is not used, and the speaker 60 is replaced with a tweeter to reproduce components above a certain frequency. The other configurations are the same as those of the first embodiment. Figure 6 is a block diagram of a conference support system 1 according to the second embodiment of the present invention. As in the previous embodiment, in the second embodiment, the sound reproduced by the tweeter is configured to be reflected by a parabolic ceiling portion 17 formed in part of the ceiling.

Here, in this specification, the first tweeter 67 is defined as a speaker that reproduces sound components of 1 kHz or more, but does not reproduce sound components below 1 kHz. The second tweeter 68 is defined as a speaker that reproduces sound components of the lower limit frequency or more of a 1/3 octave band with a center frequency of 2.5 kHz, but does not reproduce sound components below the lower limit frequency of a 1/3 octave band with a center frequency of 2.5 kHz.

The setting unit 35 in the second embodiment sets whether the electrical signals from the microphones 30, 30' are to be reproduced by the first tweeter 67 or the second tweeter 68. When playing audio by the first tweeter 67, the setting unit 35 turns the first switch 37 on and the second switch 38 off. When playing audio by the second tweeter 68, the setting unit 35 turns the first switch 37 off and the second switch 38 on.

The setting unit 35 in the second embodiment also has a function of setting whether the tweeter to be placed at the focal point F is the first tweeter 67 or the second tweeter 68. To achieve this function, it is preferable to have a drive unit 69 such as an actuator (not shown). The setting unit 35 operates this drive unit 69 to position either the first tweeter 67 or the second tweeter 68 at the focal point F. Of course, the tweeter to be placed at the focal point F may be set manually.

The settings in the setting unit 35 as described above may be performed manually by a person determining whether or not the partition 100 is present on the desk 25, or may be performed automatically, for example by acquiring an image of the desk 25 and determining whether or not the partition 100 is present on the desk 25 through image analysis or the like.

In the conference support system 1 according to the second embodiment, the conversation voice recorded by the microphones 30 and 30' has its level adjusted by the volume adjustment unit 41, and the electric signal is amplified by the amplifier 50. If the partition 100 is provided on the desk 25, the setting unit 35 sets the voice to be played by the first tweeter 67, and if the partition 100 is not provided on the desk 25, the setting unit 35 sets the voice to be played by the second tweeter 68. That is, in the second embodiment, the system amplifies and plays back the above-mentioned playback frequency band by the first tweeter 67 and the second tweeter 68, and plays back the voice by emphasizing only the frequency band containing many consonant components. According to the second embodiment, the same effect as the previous embodiment can be enjoyed.

In the conference support system 1 according to the second embodiment, either the first tweeter 67 or the second tweeter 68 is set by the setting unit 35 depending on the installation status of the partition, so that voice can be transmitted clearly to conference participants regardless of whether a transparent partition 100 is installed on the conference desk 25.

Next, another embodiment of the present invention will be described. FIG. 7 is a block diagram of a conference support system 1 according to a third embodiment of the present invention. In the conference support system 1 according to the third embodiment,
The audio processing unit 40 has an equalizer 49 that adjusts the amount of amplification for each frequency band of the electrical signals converted by the microphones 30, 30', and the level of the electrical signals passing through the equalizer 49 is adjusted by a volume adjustment unit 41 and amplified by an amplifier 50. The electrical signals amplified by the amplifier 50 are input to a speaker 60 for reproduction.

The setting unit 35 according to the third embodiment sets the equalizer 49 to either increase the amount of amplification of the frequency band equal to or greater than the first frequency (1 kHz), or to increase the amount of amplification of the frequency band equal to or greater than the second frequency (the lower limit frequency of the 1/3 octave band with a center frequency of 2.5 kHz). In the former case, it is preferable to decrease the amount of amplification of the frequency band below the first frequency (1 kHz), and in the latter case, to decrease the amount of amplification of the frequency band below the second frequency (the lower limit frequency of the 1/3 octave band with a center frequency of 2.5 kHz).

In this manner, in the conference support system 1 according to the third embodiment, when a partition 100 is provided on the desk 25, the equalizer 49 is adjusted by the setting unit 35 so that audio with the frequency band above the first frequency (1 kHz) emphasized is reproduced from the speaker 60.
Furthermore, when the partition 100 is not provided on the desk 25, the equalizer 49 is adjusted by the setting unit 35 so that sound in which the frequency band equal to or higher than the second frequency (the lower limit frequency of the 1/3 octave band with a center frequency of 2.5 kHz) is emphasized is reproduced from the speaker 60. The setting in the setting unit 35 can be either manual or automatic, as in the embodiments described above.

The conference support system 1 according to the third embodiment can provide the same effects as the previous embodiment.

In the conference support system 1 according to the third embodiment, the setting unit 35 appropriately adjusts the amount of amplification for each frequency band in the equalizer 49 depending on the installation status of the partition 100, so that voice can be transmitted clearly to conference participants regardless of whether or not a transparent partition 100 is installed on the conference desk 25.

Next, other embodiments of the present invention will be described. In the embodiments described so far, the microphone 30 is present within the range of sound presented by the speaker 60 and the parabolic ceiling portion 17, so howling is predicted to occur due to a loop in which sound is input to the microphone 30, amplified by the amplifier 50, played back from the speaker 60, and then input to the microphone 30.

Therefore, the fourth embodiment employs a configuration that suppresses such feedback.

Figure 8 is a diagram illustrating an overview of a conference support system 1 according to a fourth embodiment of the present invention. The conference support system 1 according to the fourth embodiment can be arbitrarily combined with any of the first to fourth embodiments described so far.

In Figure 8, four configurations for suppressing feedback are shown: a soundproofing plate 70 provided below the speaker 60, covers 80, 80' provided above the microphones 30, 30', microphone stands 27, 27' in the shape of a truncated cone or pyramid on which the microphones 30, 30' are placed, and sound-absorbing material 90 laid on the desk 25.

In this embodiment, each configuration may be used alone or in any combination to suppress feedback.

The soundproofing plate 70 is provided to prevent the sound reflected by the parabolic ceiling portion 17 from being picked up again by the microphone 30. It is preferable that the soundproofing plate 70 and the microphones 30 and 30' overlap in a plan view.

In addition, by providing the cover bodies 80, 80' above the microphones 30, 30', the microphones 30, 30' are prevented from picking up sound from above the microphones 30, 30', and sound is mainly collected from the speech of the conference participants.

The microphone stands 27, 27' on which the microphones 30, 30' are placed are shaped like truncated cones or truncated pyramids, and by reflecting sound from the ceiling side generally to the side, the microphones 30, 30' are prevented from picking up sound reflected by the desk 25 from below.

In addition, the sound-absorbing material 90 laid on the desk 25 absorbs sound incident from above, preventing the microphones 30, 30' from picking up sound reflected by the desk 25 from below.

In the above configuration, the conversational voice recorded by the microphones 30, 30' is amplified, and the components above 1 kHz or above the lower limit frequency of the 1/3 octave band with a center frequency of 2.5 kHz are reproduced from the speaker 60 (or tweeter) installed at the focus of the parabolic ceiling 17. Furthermore, in the conference support system 1 according to the fourth embodiment, the above-mentioned physical howling suppression measures are taken, and even if the howling frequency is within the reproduction frequency band, the diffraction effect of the sound insulation plate 70 or the sound absorption effect of the cover body 80 and the sound absorbing material 90 is high in the high frequency range, so that the amplification rate can be sufficiently increased and the audibility of the voice can be improved. Furthermore, according to the fourth embodiment, the same effects as those of the previous embodiment can be enjoyed.

Next, a fifth embodiment of the present invention will be described. The conference support system 1 according to the fifth embodiment can be used in any combination with any of the first to fourth embodiments described above.

The conference support system 1 according to the present invention is characterized in that the sound emitted from the speaker 60 installed facing upward at the focus F of the parabolic ceiling portion 17 is reflected vertically downward by the parabolic ceiling portion 17 and presented within a limited area covered by the parabolic ceiling portion 17.

In such a conference support system 1 according to the present invention, if a partition 100 is placed in the range where sound is presented (the area below the parabolic ceiling portion 17 in a plan view) as shown in FIG. 9, there is a problem in that sound reflected by the parabolic ceiling portion 17 is reflected or scattered by the partition 100, and the sound propagates outside the range covered by the parabolic ceiling portion 17 where the sound is intended to be presented. Here, the electrical system configuration of the microphones 30, 30', etc. is omitted from FIG. 9. Other examples of sound reflecting objects on the desk 25 include, for example, a display, a personal computer, a bookshelf, a desk lamp, etc.

As for the desk 25, the top surface of the tabletop is usually flat and parallel to the floor surface 20, so sound reflected by the top surface of the tabletop after being reflected by the parabolic ceiling portion 17 returns in the direction of the parabolic ceiling portion 17 and does not propagate outside the range where the sound is desired to be presented, and therefore it is not considered a sound reflector here.

To solve the above problems, in the conference support system 1 according to the fifth embodiment, a soundproofing plate 70 is arranged flush with the horizontal plane that includes the top end of the structure including the housing 61 of the speaker 60. Figure 10 is a diagram for explaining the overview of the conference support system 1 according to the fifth embodiment of the present invention. Figure 10 does not show the configuration of the electrical system, such as the microphones 30, 30'.

The speaker 60 is composed of a magnet coil section 62 that serves as a vibration source, and a cone section 65 that is vibrated by this vibration source and thus essentially serves as a vibration section that serves as a sound source.

Generally, the speaker 60 is not used by itself, but is used while housed in a housing 61 such as an enclosure. The upper surface of the soundproofing plate 70 is laid out so as to be flush with the horizontal plane that includes the top end of such housing 61. The reason for this layout will be described later.

The housing 61 does not include a metal mesh or the like that is placed in front of the cone portion 65 of the speaker 60 to protect the cone portion 65. This is because such protective materials such as metal mesh can be considered acoustically transparent. Furthermore, the housing 61 does not include tiny protrusions such as screws or bolts.

The installation range of the soundproofing board 70 is set to a range that overlaps with or exceeds the sound reflecting object in a planar positional relationship, so that the sound reflecting object is included within the range of the soundproofing board 70. However, in a planar view, the range of the soundproofing board 70 is set to be narrower than the parabolic ceiling portion 17 and does not overlap with the conference participants to whom the sound is to be presented.

The material and structure of the sound insulation board 70 need only have a certain degree of sound insulation performance (for example, an acoustic transmission loss of 10 dB or more is desirable) against the frequency components of the sound to be presented. In addition, in the embodiment shown in FIG. 10, the shape of the sound insulation board 70 is circular in a planar view, but the planar shape of the sound insulation board 70 is not particularly limited to this, and the sound insulation board 70 can be rectangular, polygonal, irregular, etc. in a planar view.

The cross-sectional shape of the sound insulation panel 70 is such that at least the upper surface is flat and parallel to the floor surface 20. However, this is based on the assumption that the general ceiling portion 15 is parallel to the floor surface 20 and the parabolic ceiling portion 17 is installed so that the sound radiated from the speaker 60 is reflected perpendicularly to the floor surface 20.

In the conference support system 1 according to the fifth embodiment, the layout is such that the soundproofing plate 70 is flush with the horizontal plane that includes the top end of the structure including the housing 61 of the speaker 60. This is for the following reasons.

Figure 11 is a diagram explaining the difference in the propagation path based on the height of the focal point F and the height of the sound-proofing plate 70. Figure 11(A) is a schematic diagram of the sound propagation path when the sound-proofing plate 70 is placed below the focal point, and Figure 11(B) is a schematic diagram of the sound propagation path when the top surface of the sound-proofing plate 70 is placed at the same height as the focal point.

As shown in FIG. 11(A), when the top surface of the soundproofing plate 70 is placed below the speaker 60, i.e., the focal point F, the sound that has traveled downward from the speaker is reflected by the top surface of the soundproofing plate 70 and then enters the parabolic ceiling portion 17. At this time, the direction of incidence coincides with the direction of incidence of the sound radiated from the virtual image F' of the focal point, which is symmetrical to the focal point with the top surface of the soundproofing plate 70 as the symmetrical plane. For this reason, the reflection direction of the sound that enters the parabolic ceiling portion 17 is not perpendicular downward to the floor surface 20, and the sound propagates outside the range that is covered by the parabolic ceiling portion 17 and is intended to be presented.

On the other hand, as shown in FIG. 11B, if the top surface of the soundproofing plate 70 is set at the same height as the top end of the housing 61 in which the speaker 60 is housed, the virtual image of the focus will be in the same position as the real image (original focus), and such a problem will not occur. For this reason, in the conference support system 1 according to the fifth embodiment, the top side of the soundproofing plate 70 is set at the same height as the top end of the housing 61 of the speaker 60. Note that setting it up in this manner is essentially equivalent to arranging the soundproofing plate 70 with its top surface flush with the horizontal plane that includes the top end of the housing 61 in which the speaker 60 is housed.

In the conference support system 1 according to the fifth embodiment, the reason why the upper surface of the sound-proofing board 70 is flat and parallel to the floor surface 20 (i.e., the horizontal plane) is as follows. Figure 12 is a schematic diagram of the sound propagation path when the upper surface of the sound-proofing board 70 is flat and parallel to the floor surface 20.

Sound (1) emitted from a speaker 60 installed at focal point F enters the parabolic ceiling portion 17 and is then reflected vertically downward (2). The sound reflected vertically downward from the parabolic ceiling portion 17 enters the top surface of the sound insulation board 70, but if the top surface of the sound insulation board 70 is flat and parallel to the floor surface, the sound that enters the top surface of the sound insulation board 70 is reflected vertically upward (3) and then reflected again from the parabolic ceiling portion 17 toward focal point F (4).

The sound is then reflected repeatedly from the focal point F of the speaker 60 → the parabolic ceiling portion 17 → the top surface of the sound-proofing plate 70 → the parabolic ceiling portion 17 → the focal point F of the speaker 60 → ... so that the sound does not propagate outside the range that is covered by the parabolic ceiling portion 17 and is desired to be presented. For this reason, the top surface of the sound-proofing plate 70 is made flat and parallel to the floor surface 20.

Next, we will explain the speaker 60 that can be used in the conference support system 1 according to the fifth embodiment of the present invention. According to the technology proposed in this invention, it is required to install the speaker 60 at the focal point F of the parabolic ceiling portion 17, and it is preferable that the speaker 60 is small in order to install it accurately at the focal position. However, a small speaker 60 generally has a wide directivity range over a wide frequency band, and as shown in FIG. 13 (electrical system not shown), there is a problem that sound that has bent over from the speaker vibration portion to the side or downward does not enter the parabolic ceiling portion 17, but instead propagates directly outside the range where the sound is intended to be presented.

By installing the soundproofing panel 70 of the conference support system 1 according to the fifth embodiment, as shown in FIG. 14 (electrical system not shown), it is possible to obtain the effect of reducing the leakage of sound to the side or below the speaker 60 in a frequency band in which the wavelength is smaller than the size of the soundproofing panel 70. This makes it possible to more reliably present sound within the range covered by the parabolic ceiling portion 17.

By using a soundproofing plate 70 like that of the fifth embodiment, it is not necessary to custom-make a speaker with a small speaker unit attached to a large housing in order to obtain the above-mentioned effect. The above-mentioned effect can be obtained by configuring a system using small speakers that are generally available on the market.

In the above configuration, of the conversational voices recorded by the microphones 30, 30', basically, components above 1 kHz or above the lower limit frequency of the 1/3 octave band with a center frequency of 2.5 kHz are amplified and reproduced from the speaker 60 installed at the focus of the parabolic ceiling portion 17. Furthermore, according to the conference support system 1 of the fifth embodiment configured as described above, it is possible to prevent the sound reflected by the parabolic ceiling portion 17 from propagating to the area below the sound insulation plate 70 in a plan view. As a result, it is possible to prevent the reproduced sound from being reflected or scattered by a reflecting object such as the partition 100 located below the parabolic ceiling, and thus prevent the sound from propagating beyond the range where it is originally intended to be presented.

In addition, in the conference support system 1 according to the fifth embodiment, even if the howling frequency is within the playback frequency band, the diffraction effect of the sound insulation panel 70 is high in the high frequency range, so it is possible to sufficiently increase the amplification rate and improve the audibility of the voice.

Furthermore, according to the fifth embodiment, it is possible to enjoy the same effects as the previous embodiments.

As described above, the conference support system according to the present invention can prevent conversations in a meeting space from being heard by other nearby workers, thereby reducing the productivity of those other workers, without the need to take measures such as surrounding the space with a partition.

The conference support system 1 according to the present invention uses either the first filter or the second filter to emphasize consonants when playing back, so that voices can be transmitted clearly to conference participants even if they are wearing masks. Furthermore, in the conference support system according to the present invention, the setting unit sets either the first filter, which is suitable when a partition is installed, or the second filter, which is suitable when a partition is not installed. Therefore, with such a conference support system according to the present invention, voices can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

In addition, the conference support system according to the present invention allows either the first tweeter or the second tweeter to be set by the setting unit depending on the installation status of the partition, so that voice can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

In addition, the conference support system according to the present invention has a setting unit that appropriately adjusts the amount of amplification for each frequency band in the equalizer depending on the installation status of the partition, so that voice can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

In addition, the conference support system according to the present invention makes it possible to increase the amplification rate of the sound reproduced from the speaker by using the above-mentioned filter, thereby sufficiently increasing the volume of the conversation sound transmitted to the speaker and conference participants.

In addition, with the conference support system of the present invention, the provision of the above-mentioned filters and tweeters makes it possible to increase the amplification rate of the sound reproduced from the speaker, thereby sufficiently increasing the volume of the conversation sound transmitted to the speaker and conference participants.

In other words, the effect of making conversational voices clearer by playing back based on the playback frequency band, and thus being able to properly transmit voice to conference participants, can be achieved without increasing the amplification rate of the playback voice. In other words, even with an amplification rate that does not cause feedback, voices can be properly transmitted to conference participants.

In addition, with the conference support system according to the present invention, when the howling frequency is outside the playback frequency band, it is possible to sufficiently increase the amplification rate, which also improves the audio transmission to conference participants.

In addition, the conference support system according to the present invention can guide speakers to reduce their speaking volume while reliably transmitting sound only to conference participants within the area covered by the parabolic surface on the ceiling.

In addition, it is possible to effectively provide feedback to the speaker of their own voice, and as a result, it is possible to more effectively guide the speaker to reduce the volume of their voice. This also reduces the degree to which conversation sounds leak into nearby spaces.

This makes it possible to reduce the amount of conversation sound that propagates to adjacent spaces. As a result, it is possible to reduce the degree of decline in the work efficiency of other workers working in adjacent spaces, reduce the degree of interference with other conversations taking place in adjacent spaces, and reduce the feeling of noise throughout the workplace.

In addition, the conference support system according to the present invention makes it possible to prevent highly confidential conversations from being leaked to those around when they are held in a meeting space.

The above effects can be achieved without increasing the amplification rate of the sound reproduced by the speaker. In other words, the degree to which the reproduced sound leaks to the surroundings can be suppressed, and the above effects can be achieved even with an amplification rate that does not cause feedback. On the other hand, if the feedback frequency is outside the playback frequency band, it is possible to increase the amplification rate sufficiently.

Even if the feedback frequency is within the playback frequency band, the diffraction effect of the shielding plate and the sound absorption effect of the sound absorbing material are high in the high frequency range, so by combining physical methods such as the shielding plate described in Patent Document 2, feedback can be effectively suppressed and the amplification rate can be sufficiently increased.

In addition, in the conference support system according to the present invention, if a microphone installed on a desk is used, there is no need for a wearable device such as an intercom, and the above-mentioned effects can be obtained without compromising convenience. Wearing an intercom or the like not only reduces convenience, but can also lead to a decrease in meeting efficiency due to the discomfort felt by workers who are not accustomed to it.

In addition, in the conference support system according to the present invention, the speaker installed at the focal point F can be a general speaker, and the above-mentioned effects can be achieved at low cost. Parametric speakers and flat panel speakers exist as speaker systems with narrow directional characteristics for playing back conversation sounds in a limited range, but they have issues with cost and sound quality.

Furthermore, the conference support system according to the present invention is effective not only for actual face-to-face conversations, but also for conversations with remote parties, such as via Web conferences.
Reference 1: Acoustics Science Series 21: Children's Voices, edited by the Acoustical Society of Japan, Corona Publishing, 2019 Reference 2: Architectural and Environmental Acoustics, 3rd Edition, Junichi Maekawa, Masayuki Morimoto, Kimihiro Sakagami, Kyoritsu Shuppan, 2011 Reference 3: "Acoustic effects of medical, cloth, and transparent face masks on speech signals," RM Corey, U. Jones, and AC Singer, J. Acoust. Soc. Am., Vol. 148, 2371, 2020. (https://doi.org/10.1121/10.0002279)
Reference 4: “Prediction model of road traffic noise “ASJ RTN-Model 2018””, Road Traffic Noise Research Committee of the Acoustical Society of Japan, Journal of the Acoustical Society of Japan, Vol. 75, No. 4, pp. 188-250, 2019.

Reference Signs List 1: Conference support system 10: Ceiling 15: General ceiling section 17: Parabolic ceiling section 20: Floor surface 25: Desk 27, 27': Microphone stand 30, 30': Microphone 35: Setting section 37: First switch 38: Second switch 40: Audio processing section 41: Adjustment section 43: Low-pass filter 44: Variable gain amplifier 45: Opening/closing switch 47: First filter 48: Second filter 49: Equalizer 50: Amplifier 60: Speaker 61: Housing 62: Magnet coil section 65: Cone section 67: First tweeter 68: Second tweeter 69: Drive section 70: Sound insulation board 80, 80': Cover body 90: Sound absorbing material 100: Partition 110: Mask

Claims (6)

A conference support system that supports a conference by collecting speech from conference participants, playing the collected speech through a speaker, and presenting the speech to the conference participants,
A microphone that converts an input audio signal into an electrical signal;
a first filter that passes only an electrical signal corresponding to a component having a first frequency or higher among the electrical signals converted by the microphone;
a second filter that passes only an electrical signal corresponding to a component having a second frequency or higher among the electrical signals converted by the microphone;
A setting unit that sets either the first filter or the second filter;
an amplifier that amplifies the electrical signal that has passed through the filter set by the setting unit;
a speaker that reproduces the electrical signal amplified by the amplifier;
a parabolic surface formed on a part of a ceiling that reflects the sound reproduced by the speaker. A conference support system that supports a conference by collecting speech from conference participants, playing the collected speech through a speaker, and presenting the speech to the conference participants,
A microphone that converts an input audio signal into an electrical signal;
an amplifier for amplifying the electrical signal converted by the microphone;
a first tweeter that reproduces only an electrical signal corresponding to a component having a first frequency or higher among the electrical signals amplified by the amplifier;
a second tweeter that reproduces only an electrical signal corresponding to a component having a second frequency or higher among the electrical signals amplified by the amplifier;
A setting unit that sets either the first tweeter or the second tweeter;
a parabolic surface formed on a part of a ceiling that reflects sound reproduced by the tweeter set by the setting unit. A conference support system that supports a conference by collecting speech from conference participants, playing the collected speech through a speaker, and presenting the speech to the conference participants,
A microphone that converts an input audio signal into an electrical signal;
an equalizer that adjusts the amount of amplification for each frequency band of the electrical signal converted by the microphone;
a setting unit that sets whether to increase an amount of amplification of a frequency band equal to or higher than a first frequency or to increase an amount of amplification of a frequency band equal to or higher than a second frequency by the equalizer;
an amplifier that amplifies the electrical signal that has passed through the equalizer;
a speaker that reproduces the electrical signal amplified by the amplifier;
a parabolic surface formed on a part of a ceiling that reflects the sound reproduced by the speaker. The conference support system according to claim 1 or 3, characterized in that the first frequency is 1 kHz. The conference support system according to claim 1 or 3, characterized in that the second frequency is the lower limit frequency of a 1/3 octave band with a center frequency of 2.5 kHz. The conference support system according to any one of claims 1 to 5, characterized in that a soundproof panel is arranged below the speaker.

Images