WO2010095620A1

WO2010095620A1 - Sound field creation device

Info

Publication number: WO2010095620A1
Application number: PCT/JP2010/052290
Authority: WO
Inventors: 敏樹羽入
Original assignee: 学校法人日本大学
Priority date: 2009-02-17
Filing date: 2010-02-16
Publication date: 2010-08-26
Also published as: JP5505763B2; JP2010193105A

Abstract

Provided is a sound field creation device which can eliminate intracerebral localization or unnatural feeling of localization. A sound field creation device which creates a sound field consists of a speaker (20), a reflection sound creation section (30), an open headphone (40), and a signal processing section (50). The speaker (20) outputs a sound from a sound source (10). The reflection sound creation section (30) creates a reflection sound based on the sound from the sound source (10). The open headphone (40) outputs the reflection sound from the reflection sound creation section (30). The signal processing section (50) delays the reflection sound outputted from the open headphone (40) such that the reflection sound outputted from the open headphone (40) arrives at the ear of a listener later than the sound outputted from the speaker (20).

Description

Sound field creation device

The present invention relates to a sound field creation device, and more particularly, to a sound field creation device that creates a sound field using a speaker and open headphones.

In the listening room, the technology to reproduce the sound field in a completely different space such as a concert hall is called sound field creation technology or sound field reproduction technology. Conventionally, sound field reproduction techniques include a multi-channel reproduction system using a plurality of speakers installed around a listener, a headphone system that reproduces sound processed based on a head-related transfer function using headphones, and the like.

The multi-channel playback system using a plurality of speakers has a high sense of reality in the sound field, but there are problems in that it is difficult to secure a place for installing a plurality of speakers and to connect the speakers to an amplifier, a tuner, and the like. Furthermore, there is a problem that the listening point of the listener is limited and the effect of creating the sound field is greatly changed when the listener moves.

The headphone system is a solution to the above problems. If playback is performed using headphones, there are few problems with connection, and the position of the sound generation unit is fixed at the position of the ear, so that the listening point is not limited.

Also, a system using speakers and open headphones that can hear external sounds has been developed. For example, Patent Document 1 discloses a sound field reproduction apparatus that reproduces a front sound with a speaker and a rear sound with an open headphone in order to obtain a realistic sound field without arranging a rear speaker. ing. Further, in Patent Document 2, in order to provide a sound field that is easy to hear without giving a sense of blockage to a passenger in the rear seat of an automobile, frequency characteristic adjustment, delay time, and amplification factor are provided for signals of a plurality of channels. A sound field reproduction device that reproduces a synthesized sound subjected to the above adjustment from an open type headphone is disclosed.

JP 2000-78699 A JP 2008-98694 A

However, in the headphone system, there is a problem that the sound image of the reproduced sound is formed inside the head, and it feels like the sound is sounding in the head. This is a phenomenon called localization in the head. Conventionally, head localization has been attempted to be resolved by outputting a signal obtained by convolving the head-related transfer function with a sound source. However, in the convolution processing of the head related transfer function or the like, the out-of-head localization has not been achieved, and the in-head localization has not been sufficiently solved.

Furthermore, as a problem specific to the headphone system, there is a problem that the direction of sound generation is fixed to the movement of the listener and the rotation of the head. Specifically, for example, when a listener is watching an orchestra DVD with a video, if the head is rotated left or right with respect to the front where the monitor for displaying the video is arranged, the orchestra video is moved forward. In spite of this, the headphones are fixed to the head, so the sound can be heard from the direction of the front of the head. As described above, in the headphone system, unnatural sound localization is also a problem.

The device described in Patent Document 1 is intended to eliminate the rear speaker, and the device described in Patent Document 2 is intended to prevent the listener from feeling blocked, and the headphones described above. The problem of in-head localization and unnatural localization in reproduction has not been solved at all.

In view of such circumstances, the present invention intends to provide a sound field creation device that eliminates in-head localization and unnatural localization.

In order to achieve the above-described object of the present invention, a sound field creation device according to the present invention includes one or more speakers that output sound from a sound source, and reflected sound generation that generates reflected sound based on the sound from the sound source. And an open headphone that outputs the reflected sound from the reflected sound generator, and the open sound so that the reflected sound output from the open headphone reaches the listener's ear after the sound output from the speaker. A signal processing unit that delays the reflected sound output from the headphones.

Here, the reflected sound generation unit may generate the reflected sound using the head-related transfer function.

Further, the reflected sound generation unit may generate a reflected sound that becomes a reverberant sound.

Furthermore, the reflected sound generation unit may generate a reflected sound that becomes a reverberant sound.

Further, in order to change the sound field felt by the listener, a level adjusting unit that changes the ratio of the magnitude of the reflected sound output from the open headphones and the sound output from the speaker may be provided. .

Furthermore, the signal processing unit may be configured to change the sound field felt by the listener by changing the delay time of the reflected sound output from the open headphones.

In addition, the microphone includes a microphone that receives sound output from the speaker, the microphone is disposed in the vicinity of the open-type headphones, and the reflected sound generation unit is configured to generate reflected sound from the sound received by the microphone. You may do it.

The sound field creation device according to the present invention includes a microphone that receives sound, a reflected sound generation unit that generates reflected sound based on sound received by the microphone, and a microphone disposed in the vicinity, Headphone that outputs the reflected sound from the head and the headphone output so that the reflected sound that is output from the headphone reaches the listener's ear after the sound received by the microphone. And a signal processing unit that delays the reflected sound.

The sound field creation device of the present invention has an advantage that it is possible to eliminate in-head localization and unnatural localization. There is also an advantage that an arbitrary sound field can be created by eliminating the influence of the sound receiving environment.

FIG. 1 is a schematic block diagram for explaining the configuration of the sound field creation device of the first embodiment of the present invention. FIG. 2 is a schematic block diagram for explaining the configuration of the sound field creation apparatus of the second embodiment of the present invention.

Hereinafter, modes for carrying out the present invention will be described together with illustrated examples. FIG. 1 is a schematic block diagram for explaining the configuration of the sound field creation device of the first embodiment of the present invention. As shown in the figure, the sound field creation device of the present invention mainly includes a sound source 10, a speaker 20, a reflected sound generation unit 30, an open type headphone 40, and a signal processing unit 50.

The sound source 10 supplies sound that is the source of the sound field created by the sound field creation device of the present invention. The sound to be supplied may be any sound. Specifically, any device that reproduces sound information recorded on, for example, a music CD or DVD may be used. The sound to be reproduced may be a stereo sound or a monaural sound, or may be a multi-channel signal such as 5.1ch. Furthermore, it may be a sound that includes a reflected sound or a direct sound that does not include a reflected sound.

The speaker 20 outputs the sound from the sound source 10. There may be at least one speaker 20. That is, only one speaker is sufficient for monaural reproduction, and at least two speakers are sufficient for stereo reproduction. Further, in the case of multi-channel such as 5.1ch, for example, three speakers for reproducing the front channel may be used. Moreover, the arrangement | positioning location of the speaker 20 is not specifically limited. In the sound field creation device of the present invention, if the speaker is arranged in front of the listener, the listener recognizes that the sound is generated from the front. Therefore, for example, when viewing an orchestra DVD with video, if it is placed near the front monitor, the listener feels that sound is being generated from the direction of the orchestra displayed on the monitor. In addition, the speaker of the sound field creation apparatus of this invention is not limited to a specific thing, What is necessary is just generally available.

The reflected sound generation unit 30 generates a reflected sound based on the sound from the sound source 10. Specifically, the direct sound generated from the speaker 20 is artificially created as a sound that is reflected on a wall or ceiling and reaches the listener's ear. The reflected sound is a concept including a reverberant sound and a reverberant sound as described later. The reflected sound generation unit 30 adds a three-dimensional sound spread. If the original sound of the sound source 10 includes a reverberation sound or a reverberation sound, the reflected sound generation unit 30 generates a reflected sound by using the sound. Even when the original sound of the sound source 10 includes only direct sound, a reflected sound may be generated in a pseudo manner as described below.

For example, the reflected sound generating unit 30 may generate several reflected sounds when generating a reflected sound that becomes a reverberant sound. Note that a single reflected sound means a simulated one route from the sound emitted from a sound source reflected on a wall or the like to reach the listener's ear. The reflected sound generator 30 calculates several of these using the head-related transfer function. The head-related transfer function represents a change in sound caused by peripheral objects including the ear shell, the human head, and the shoulder as a transfer function. By generating several reflected sounds, it becomes a reverberant sound and can express a three-dimensional sound spread.

In addition, when the reflected sound generating unit 30 generates a reflected sound that becomes a reverberant sound, the reflected sound generating unit 30 may generate a large number of reflected sounds using a head-related transfer function. A reverberant sound can be expressed by convolving a head-related transfer function of a large number of reflected sounds.

The reflected sound can be variously changed depending on the sound field to be created. For example, the reflected sound may be appropriately selected according to the reflected sound in the sound field environment to be created, such as a concert hall or a live house.

Thus, in the sound field creation device of the present invention, if the original sound of the sound source includes a reflected sound, the reflected sound generation unit 30 uses only a few reflected sounds while taking advantage of the reverberation feeling. A three-dimensional sound spread may be added by using the head-related transfer function. If only the direct sound is included, in order to add both a reverberation feeling and a three-dimensional expansion, the reflected sound generation unit 30 converts the reflected sound into a head related transfer function based on the direct sound. May be used.

The open-type headphones 40 output the reflected sound from the reflected sound generating unit 30 described above. That is, only the reflected sound is output from the open type headphones 40. As described later, the reflected sound generated by the reflected sound generation unit 30 is output by the open headphones 40 via the signal processing unit 50. The open headphone 40 is also called, for example, an open air headphone, and the back surface of the sound generation unit is open so that external sounds can freely enter and exit. Further, a space may be provided not only on the back surface portion of the headphones but also on the ear surface portion side. The open headphones of the sound field creation device of the present invention are not limited to specific ones, and may be any generally available headphones.

When the listener wears such an open type headphone 40, the listener listens to the sound from the sound source 10 from the speaker 20 and listens to the reflected sound from the open type headphone 40. Since the open headphone 40 is used, it does not interfere with listening to the sound output from the speaker 20.

The signal processing unit 50 delays the reflected sound output from the open headphone 40 so that the reflected sound output from the open headphone 40 reaches the listener's ear after the sound output from the speaker 20. It is something to be made. That is, the reflected sound from the reflected sound generation unit 30 is subjected to delay processing so that the sound output from the speaker 20 reaches the listener's ear earlier than the sound output from the open headphones 40. As a specific example of the delay amount, for example, when the distance between the speaker 20 and the listener is 3 meters, if the delay is about 0.009 seconds, that is, 9 milliseconds or more, the sound from the speaker 20 becomes faster. It reaches the listener's ear. Therefore, for example, 10 milliseconds or more including 1 millisecond may be set as the delay amount so that a synthesized sound image of the sound output from the speaker 20 and the sound output from the open headphone 40 cannot be formed. Note that the delay amount may be appropriately changed according to the distance between the speaker 20 and the open headphones 40.

Furthermore, the sound field felt by the listener may be changed by changing the ratio of the magnitude of the reflected sound output from the open headphones 40 and the sound output from the speaker 20. For example, the level adjustment unit 55 is disposed between the sound source 10 and the speaker 20. The level adjustment unit 55 can adjust the loudness of the speaker 20. When the reflected sound output from the open headphones 40 is constant and the sound output from the speaker 20 is increased by the level adjusting unit 55, it can be felt as if it is approaching a sound source. Conversely, if the sound output from the speaker 20 is reduced, it can be felt as if the sound source has moved away. For example, the sound field felt by the listener may be changed by increasing or decreasing the reflected sound generated by the reflected sound generating unit 30 and output from the open headphones 40 by, for example, the signal processing unit 50. Thus, the sound field creation device of the present invention can perform various controls such as a sense of distance to the sound source, a sense of reverberation, and a sense of spread by changing the ratio of the loudness.

Also, the signal processing unit 50 may change the sound field felt by the listener by changing the delay time of the reflected sound output from the open headphones 40. For example, if the delay time is lengthened, the reflected sound is heard with a delay, so that it can be felt in a wide space. On the contrary, when the delay time is shortened, the reflected sound can be heard immediately, so that it can be felt in a narrow space. As described above, the sound field creation apparatus of the present invention can create various sound fields by changing the delay time of the reflected sound generated by the reflected sound generation unit and output from the open headphones. It may be configured. Of course, various combinations of the ratio between the delay time and the loudness may be used.

In the illustrated example described above, the signal processing unit 50 performs a delay process on the output of the reflected sound generation unit 30 or changes the ratio of the sound volume and the delay time. It is not limited, and various signal processing may be applied to the output of the open type headphone 40 that is finally output. Therefore, the signal processing unit 50 is arranged between the sound source 10 and the reflected sound generation unit 30, and is configured so that the reflected sound generation unit 30 generates a reflected sound after performing signal processing on the output from the sound source 10 in advance. May be.

Furthermore, the signal processing unit 50 may be configured to output sound processed using an effector, an amplifier, a filter, or the like from the speaker 20 or the open headphones 40 as necessary.

The operation and effect of the sound field creation device of the present invention configured as described above will be described. As described above, in the sound field creation device of the present invention, the sound from the sound source output from the speaker 20 first reaches the listener's ear, and then the reflected sound output from the open headphones 40 is received. To reach.

Here, it is known that human hearing has the first wavefront law of feeling the direction of the sound with respect to the sound first heard. According to this law, if the second wavefront is delayed by, for example, 1 millisecond or more so that the second wavefront is heard after the first wavefront, the sound direction of sound is localized in the direction of the first wavefront. That is, in the sound field creation device of the present invention, the sound of the speaker 20 is heard first, so that the direction of the sound is localized in the direction of the speaker 20. Therefore, when synthesized with the reflected sound output from the open headphones 40, the listener feels that the sound has been localized outside the head. That is, the reflected sound that can be localized in the head because of the headphone output is pulled out of the speaker by the law of the first wavefront and is localized outside the head.

Therefore, according to the sound field creation device of the present invention, the listener can eliminate the localization in the head by the speaker while feeling the three-dimensional sound spread by the reflected sound from the open headphones. .

Furthermore, according to the sound field creation device of the present invention, even if the listener rotates his / her head, the position of the speaker is fixed, so that the direction of sound production is always localized in the direction of the speaker. Therefore, it is possible to eliminate unnatural localization. Thus, according to the sound field creation device of the present invention, it is possible to create a sound field without installing a speaker next to or behind the listener.

Next, a sound field creation device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic block diagram for explaining a sound field generating apparatus according to the second embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts.

As shown in the figure, the sound field creation device according to the second embodiment of the present invention is based on the sound field creation device according to the first embodiment, and further includes a microphone 60. The microphone 60 is configured to receive sound output from the speaker 20 and is disposed in the vicinity of the open headphones 40. For example, the microphone 60 may be installed integrally with the open type headphones 40. By arranging the microphone 60 in the vicinity of the open headphones 40, the sound from the speaker 20 can be received by the microphone 60 at the timing when the sound output from the speaker 20 reaches the listener.

The microphone 60 may be a stereo microphone or a monaural microphone, and may be a multi-channel microphone using a plurality of microphones. Moreover, it is not limited to a specific thing, What is necessary is just generally available.

In the sound field creation device according to the first embodiment of the present invention, the reflected sound generation unit 30 is configured to generate the reflected sound based on the sound from the sound source 10, but in the second embodiment, the reflected sound generation is performed. The unit 30 is configured to generate a reflected sound from the sound received by the microphone 60. That is, in the first embodiment, the sound from the sound source 10 is directly input to the reflected sound generation unit 30 to generate the reflected sound, but in the second embodiment, the sound from the sound source 10 is output from the speaker 20. The sound received by the microphone 60 is input to the reflected sound generation unit 30 to generate the reflected sound. Therefore, in the sound field creation device of the second embodiment, the sound from the sound source 10 is indirectly input to the reflected sound generation unit 30.

In the sound field creation apparatus of the second embodiment of the present invention configured as described above, sound is always input to the reflected sound generation unit 30 at the same timing as the sound that reaches the listener from the speaker 20. Therefore, in the signal processing unit 50, it is sufficient to set a predetermined delay amount without being affected by the distance between the speaker 20 and the open headphones 40.

Furthermore, in the sound field reproduction apparatus according to the second embodiment of the present invention, the sound output from the speaker 20 is received by the microphone 60 in the listening environment, and the received sound is input to the reflected sound generation unit 30. The reflected sound generation unit 30 can also perform a filter process or the like so as to eliminate the influence of the listening environment from the received sound. This makes it possible to create an arbitrary sound field by eliminating the influence of the sound receiving environment to some extent.

The sound field reproduction apparatus according to the second embodiment of the present invention is a level for changing the ratio of the magnitude of the reflected sound output from the open headphones and the sound output from the speaker, as in the first embodiment. An adjustment unit may be provided, and the delay time may be changed as appropriate.

Here, in the sound field creation device of the second embodiment of the present invention described above, the sound from the sound source 10 is reproduced by the speaker 20 and received by the microphone 60 disposed in the vicinity of the open headphones 40. Met. However, the present invention is not limited to this, and the sound received by the microphone is not limited to the sound output from the speaker. That is, a raw sound may be used without using a sound source or a speaker. For example, it is possible to arbitrarily control the sound field of a concert hall or the like by using the sound field creation device of the second embodiment of the present invention when listening to a live performance without using a music CD or the like. That is, the sound field creation apparatus of the second embodiment of the present invention only needs a microphone, an open type headphone, a reflected sound generation unit, and a signal processing unit.

It should be noted that the sound field creation device of the present invention is not limited to the above-described illustrated examples, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, in the illustrated example, the reflected sound generation unit and the signal processing unit are illustrated separately from the open headphones, but the present invention is not limited to this, and these functions are incorporated in the open headphones, and the integrated sound is generated. Of course, it may be used as a field creation device.

DESCRIPTION OF SYMBOLS 10 Sound source 20 Speaker 30 Reflected sound production | generation part 40 Open type headphone 50 Signal processing part 55 Level adjustment part 60 Microphone

Claims

A sound field creation device for creating a sound field, the sound field creation device comprising:
One or more speakers that output sound from the sound source;
A reflected sound generating unit that generates a reflected sound based on the sound from the sound source;
An open type headphone that outputs the reflected sound from the reflected sound generation unit;
A signal processing unit that delays the reflected sound output from the open-type headphones so that the reflected sound output from the open-type headphones reaches the listener's ear with a delay from the sound output from the speakers;
A sound field creation device comprising:
2. The sound field creation device according to claim 1, wherein the reflected sound generation unit generates a reflected sound using a head-related transfer function.
3. The sound field creation device according to claim 1 or 2, wherein the reflected sound generation unit generates a reflected sound that becomes a reverberation sound.
3. The sound field creation device according to claim 1 or 2, wherein the reflected sound generation unit generates a reflected sound that becomes a reverberation sound.
5. The sound field creation device according to claim 1, further comprising: a reflected sound output from the open headphones and the speaker for changing a sound field felt by a listener. A sound field creation device comprising a level adjustment unit that changes a ratio of a volume to an output sound.
The sound field creation device according to any one of claims 1 to 5, wherein the signal processing unit changes a delay time of a reflected sound output from the open headphones, thereby making a sound felt by a listener. A sound field creation device characterized by changing the field.
The sound field creation device according to any one of claims 1 to 6, further comprising a microphone that receives sound output from the speaker, and the microphone is located near the open headphones. The sound field creation device, wherein the reflected sound generation unit is configured to generate a reflected sound from a sound received by the microphone.
A sound field creation device for creating a sound field, the sound field creation device comprising:
A microphone to receive sound,
A reflected sound generator for generating a reflected sound based on the sound received by the microphone;
The microphone is disposed in the vicinity, and an open type headphone that outputs the reflected sound from the reflected sound generation unit;
A signal processing unit for delaying the reflected sound output from the open-type headphones so that the reflected sound output from the open-type headphones reaches the listener's ear with a delay from the sound received by the microphone; ,
A sound field creation device comprising: