JP2009141880A - Headphone device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a reproduction sound in a headphone device by suppressing an unneeded reverberation sound. <P>SOLUTION: In the headphone device, a housing inner-wall section 4R, namely a part for mounting drive units SPu-f(LF), SPu-C(R), SPu-RF, SPu-RS, SPu-f(LS), is formed in a recessed polyhedron shape. A shape and a structure for irregularly reflecting sound released from the drive units are provided, for example, by finely mounting a member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a headphone device.

A headphone device has been widely used for a long time since it can listen to a sound at a sufficient volume for a listener who uses the headphone device without causing a loud sound to resonate.
In addition, in the past, a headphone device was generally provided with one driver for each of left and right corresponding to two stereo channels. For example, as shown in Patent Document 1, a plurality of headphone devices are provided on the left and right. What has been configured to be able to perform surround playback by providing a driver is becoming known.

JP 2001-61197 A

By the way, a certain amount of space is formed in the inner wall side portion of the housing in which the driver is provided in the headphone device. Depending on how the reproduced sound is reflected in this space, the reproduced sound quality may be deteriorated. .
In particular, in the headphone device provided with a plurality of drivers on the left and right as disclosed in Patent Document 1, it is necessary to secure an area sufficient to attach the driver, and the inner wall portion of the housing needs to have a large area. There is a possibility that the space formed by the portion becomes larger and the reproduction sound quality deteriorates easily.

In view of the above problems, the present invention is configured as a headphone device as follows.
In other words, the housing inner wall portion, which is the mounting portion of the drive unit, is formed so that the sound emitted from the drive unit is irregularly reflected in the housing portion provided with one or more drive units corresponding to one ear.

  In the headphone device configured as described above, the sound emitted from the drive unit is diffusely reflected on the inner wall portion of the housing. In other words, for example, it is possible to avoid a state where the sound emitted from the drive unit and reflected by the inner wall of the housing reaches the ear intensively.

  Thereby, depending on the headphone device according to the present invention, unnecessary reverberation sound that the listener listens to is suppressed, and the quality of the reproduced sound is improved.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below.
In the present embodiment, as the headphone device, for example, a headphone device that is provided in an acoustic reproduction system that virtually realizes sound image localization obtained by a multi-channel configuration typified by 5.1ch surround is cited.

Therefore, prior to the description of the present embodiment, first, a basic concept of a technique for realizing virtual sound image localization by headphone reproduction will be described.
In the description here, the simplest example of sound image localization of a sound source is given. In other words, a case is considered where the sound image localization of a single sound source having a certain positional relationship with the listener is virtually reproduced by the headphones. For example, as schematically shown by the acoustic model of FIG. 9, this is understood as a relationship between the listener M and one sound source Src that is assumed to be at a constant angle and a fixed distance with respect to the listener M. be able to. As shown in this figure, the sound emitted from the sound source Src is given to the listener M's left ear so that the transfer function H1 is convoluted and transmitted, and to the right ear, the transfer function Hr. Is given and transmitted.
Here, the transfer functions Hl and Hr are head-related transfer functions corresponding to sound transfer characteristics from the sound source to the eardrum of the listener. Further, since the sound source Src in this case is located on the left side in front of the listener M, among the sounds that reach the left and right ears of the listener M from the sound source Src, the sound that reaches the left ear is The sound that reaches the right ear is a crosstalk component that can be heard by the right ear by diffracting the sound that can be heard by reaching the left ear. Therefore, it can be handled as a sub audio component with respect to the main audio component.

FIG. 10 shows the frequency characteristic A of the sound by the path of the transfer function H1 that is emitted from the sound source Src and listened to by the listener M's left ear in FIG. The frequency characteristic B of the sound according to the path of the transfer function Hr, which is assumed to be listened to.
As described above, since the sound source Src in this case is located at the left front of the listener M, the sound heard by the listener M's left ear is directly sound. On the other hand, the sound heard by the listener M's right ear is an indirect sound and a crosstalk component. As the difference between the frequency characteristic B and the frequency characteristic A, the sound pressure of the frequency characteristic B is smaller corresponding to this.

In this way, the sound that is emitted from one sound source Src and reaches and listens to the left and right ears has different frequency characteristics. Further, as shown in FIG. 9, there is a distance difference Ds between the distance from the sound source Src to the left ear and the distance to the right ear, and the sound source Src emits according to the distance difference Ds. An arrival time difference dl, which is a time difference in which the received sound reaches the left and right ears, is also generated. The transfer functions Hl and Hr shown in FIG. 9 give such characteristic differences such as frequency characteristic difference and arrival time difference to the original sound that is supposed to be emitted from the sound source Src.
The sound image localization ability of a person is based on a difference in predetermined characteristics such as a frequency characteristic difference (including a volume difference element in this case) and a time difference between sounds to be heard between the left ear and the right ear as described above. It is said to perceive the sense of localization of the sound image. Based on this, in order to reproduce the virtual sound image localization of one sound source with headphones, the above-described signal characteristic difference corresponding to the main sound component and the sub sound component is given based on the sound signal of the original sound. Two audio signals are obtained, one of these audio signals is reproduced and output from the drive unit corresponding to the left ear, and the other is reproduced and output from the drive unit corresponding to the right ear.

Based on the above, as shown in the acoustic model of FIG. 11, the sound image localization assumed to be obtained by the left sound source Srcl and the right sound source Scrr arranged on the left and right front with respect to the listener M is reproduced with headphones. Consider the case.
In this case, first, the sound emitted from the left sound source Srcl reaches the left ear of the listener M to which the transfer function Hll is given as the main voice, and reaches the right ear with the transfer function Hlr given as the auxiliary voice. It is supposed to be. In addition, the sound emitted from the right sound source Scrc reaches the right ear of the listener M to which the transfer function Hrr is given as the main voice, and the transfer function Hrl is given to the listener M as the auxiliary voice. It is supposed to reach.

The configuration shown in FIG. 12 can be considered as the configuration of the signal processing system for realizing the sound image localization by the left and right front shown in FIG. 11 by reproducing the headphones.
First, in the configuration shown in FIG. 12, the input signal corresponds to the original sound signal S1 corresponding to the original sound emitted from the left sound source Srcl in FIG. 11 and the original sound emitted as the right sound source Scrc in FIG. The original audio signal Sr is input.
The original audio signal Sl is branched into a system that is directly input to the synthesizer 13a and a system that is input from the filter 11b to the synthesizer 13b via the delay unit 12b. The original audio signal Sr is also branched into a system that is directly input to the synthesizer 13b and a system that is input from the filter 11a to the synthesizer 13a via the delay device 12a.

The synthesizer 13a synthesizes the directly input original audio signal S1 and the signal obtained by processing the original audio signal Sr with the filter 11a and the delay device 12a as described above, and outputs the left (L) output channel. As a signal for use, the drive unit SPu-L corresponding to the left ear is output as sound.
Further, the synthesizer 13b synthesizes the directly input original audio signal Sr and the signal obtained by processing the original audio signal S1 with the filter 11b and the delay unit 12b to obtain a right (R) output channel signal. The drive unit SPu-R corresponding to the right ear is output as sound.
In actuality, these drive units are, for example, parts that have a diaphragm made of a predetermined material shape and reproduce sound by driving the diaphragm with a drive current obtained by amplifying an audio signal. . In other words, the speaker is configured to reproduce sound near the ear, such as headphones.

In the configuration shown in FIG. 12, the system in which the original audio signal S1 is directly input to the synthesizer 13a and reaches the drive unit SPu-L corresponds to the main audio component that reaches the left ear from the left sound source Srcl. This is equivalent to giving a signal characteristic corresponding to the transfer function Hll as described later. On the other hand, the system in which the original audio signal S1 reaches the drive unit SPu-R via the filter 11b, the delay unit 12b, and the synthesizer 13b corresponds to the sub audio component that reaches the right ear from the left sound source Srcl. Then, a signal characteristic difference (frequency characteristic difference, arrival time difference dl) with respect to the main audio component is given by the filter 11b and the delay unit 12b, thereby giving a signal characteristic equivalent to the convolution of the transfer function Hlr. .
Similarly, a system in which the original audio signal Sr is directly input to the synthesizer 13b and reaches the drive unit SPu-R corresponds to the main audio component that reaches the right ear from the right sound source Scrc and corresponds to the transfer function Hrr. A system in which the original audio signal Sr reaches the drive unit SPu-L via the filter 11a, the delay unit 12a, and the synthesizer 13a is assumed to have a signal characteristic, and the sub audio component that reaches the left ear from the right sound source Src. By providing a characteristic difference with respect to the main audio component by the filter 11a and the delay unit 12a, a signal characteristic equivalent to that obtained by convolution of the transfer function Hlr is provided.

For example, as a general thing about the two-channel stereo headphones by L and R, the characteristics of the sound reproduced in the housing, including the frequency characteristics of the reproduced sound of the drive unit, are actually worn by the listener. It is set so that the balance of the frequency band can be heard naturally when listening to the sound reproduced inside the right and left ear housings. From this, at the stage of sound reproduction by the headphone device, for example, the reproduction function of each channel of L and R corresponds to each channel, and the transfer function corresponding to the path to reach the left and right ears. Can be considered as approximately given. Note that a multi-channel (5.1ch) compatible headphone device corresponding to the present embodiment, which will be described later, is also provided with a drive unit, for example, on the premise of this.
Based on the above, at least a system in which the signal S1, which is the main audio component in FIG. 12, is directly input to the combiner 13a and reaches the drive unit SPu-L, and the signal Sr is directly input to the combiner 13b. The system that is input and reaches the drive unit SPu-R is equivalent to the fact that the transfer functions Hll and Hlr are convoluted by outputting the sound from the drive unit without any filtering or delay processing. In other words, it can be understood that a sound with a characteristic can be obtained.
In addition, as described above, with respect to the sub audio component corresponding to the main audio component, a frequency characteristic difference and arrival time difference with respect to the main audio component corresponding to the transfer function are given by the filter and the delay unit. To be done.
As a result, the main sound by the transfer function Hll that should reach the left ear from the left sound source Srcl and the sub-voice by the transfer function Hlr that should reach the right ear are reproduced and output from the drive units SPu-L and SPu-R, respectively. Therefore, if this sound component is heard, it can be perceived that the left sound source Srcl is localized at an appropriate position. Similarly, the main sound based on the transfer function Hrr that should reach the right ear from the right sound source Scrc and the auxiliary sound based on the transfer function Hrl that should reach the left ear are reproduced and output from the drive units SPu-R and SPu-L, respectively. Therefore, when listening to this sound component, it can be perceived that the right sound source Scrc is localized at an appropriate position. In other words, the listener can perceive a sound image in which the left sound source Srcl and the right sound source Scrr are localized at appropriate positions in the left and right front, and virtual sound image localization is realized.

  Here, FIG. 13 shows the relationship between the headphone device corresponding to the system configuration shown in FIG. 12 and the listener's head. The headphone device in this case has a left housing part 1L and a right housing part 1R corresponding to each of the left and right ears of the listener M as shown in the figure. Although not shown here, for example, the left housing part 1L and the right housing part 1R are connected by a headband or the like, and a structure that can be mounted on the head is adopted. Then, one drive unit SPu-L and one SPu-R are attached to the left housing part 1L and the left housing part 1R, respectively, and when the headphone device is properly mounted on the head, the drive unit SPu- L and SPu-R are placed at optimum positions where they can be heard by the left ear and the right ear, respectively.

  Next, a configuration of a headphone sound reproduction system corresponding to a more practical multi-channel configuration based on the configuration corresponding to the two sound sources (two-channel configuration) described with reference to FIGS. 11 to 13 will be described with reference to FIGS. Will be described with reference to FIG. Here, a case where the multi-channel configuration is adapted to the 5.1ch surround standard is taken as an example.

First, FIG. 14 schematically shows a model of 5.1 channel surround channel configuration.
As is well known, 5.1ch surround is also referred to as a subwoofer such as LF (Left Front) ch, C (Center) ch, RF (Right Front) ch, LS (Left Surround) ch, and RS (Right Surround) ch. A channel configuration with a total of 6 channels of LFE (Low Frequency Effect) ch is assumed. For these channels, for example, the sound source position standardized by the ITU (International Telecommunication Union) recommendation (ITU-R BS.775-1) or the like, that is, the position and height of the speaker with respect to the listening position (listener M). It is prescribed. However, for LFEch, the reproduction frequency band is considerably low relative to other channels, so the directivity is low, and it is difficult for listeners to feel a clear localization, so the definition of the sound source position is loose. It is said that.

In addition, in FIG. 14, speakers SP-LF, SP-C, SP-RF, SP-LS, SP-RS, and SP-LFE are used as sound sources corresponding to LFch, Cch, RFch, LSch, RSch, and LFEch. A model is shown in which the listener M listens to the sound output from these speakers and reaching the left and right ears respectively.
For example, as the positions of these speakers in accordance with the 5.1ch surround standard, the speaker SP-LF is disposed at the left front with respect to the position of the listener M, the speaker SP-C is disposed at the center front, and the speaker is disposed at the right front. The SP-RF is arranged, the speaker SP-LS is arranged at the left rear, and the speaker SP-RS is arranged at the right rear.

Then, according to FIG. 11, the following transfer function (head-related transfer function) is used for the sound path from each speaker to the right ear and left ear of the listener M under the channel configuration shown in FIG. ).
Hfl: Transfer function of the path reaching the left ear as the main audio component from the speaker SP-LF Hlfr: Transfer function of the path reaching the right ear as the sub audio component from the speaker SP-LF Hcl: Main audio / from the speaker SP-C Transfer function of a path reaching the left ear as a sub audio component Hcr: Transfer function of a path reaching from the speaker SP-C to the right ear as a sub audio / main audio component Hrfl: From the speaker SP-RF to the left ear as a sub audio component Transfer function of the path to reach Hrfr: Transfer function of the path reaching the right ear as the main audio component from the speaker SP-RF Hlsl: Transfer function of the path reaching the left ear as the main audio component from the speaker SP-LS Hlsr: Speaker SP -Transfer function Hrsl of a path reaching the right ear from the LS as a sub audio component Hrsl: Transfer function H of a path reaching the left ear as a sub sound component from the speaker SP-RS rsr: transfer function of the path from the speaker SP-RS to the right ear as the main audio component

FIG. 15 shows an example of a headphone playback system that is based on the basic concept shown in FIGS. 11 and 12 and that supports 5.1 ch surround.
First, also in this figure, as a drive unit, a pair of drive units SPu-L and SPu-R corresponding to the left output channel and the right output channel are provided. The drive unit SPu-L receives the left output channel audio signal obtained by synthesizing the input audio signal by the synthesizer 13a, and the drive unit SPu-R obtains the input audio signal by the synthesizer 13b. The received right output channel audio signal is input.

In addition, the audio signal of each channel as 5.1ch surround is distributed and input to the combiners 13a and 13b as follows.
First, the LFch original audio signal is directly input to the synthesizer 13a, and is input to the synthesizer 13b via the filter 11b and the delay value 12b.
The RFch original audio signal is directly input to the synthesizer 13b and is input to the synthesizer 13a via the filter 11a and the delay unit 12b.
The Cch original audio signal passes through the filter 11e and the delay device 12e and is branched into two systems, and the signals of each system are input to the synthesizer 13a and the delay device 13b, respectively.
The original LSch audio signal is input to the synthesizer 13a via the filter 11d and the delay unit 12d, and is input to the synthesizer 13b via the filter 11g and the delay unit 12g.
The RSch original audio signal is input to the synthesizer 13a via the filter 11c and the delay unit 12c, and is input to the synthesizer 13b via the filter 11f and the delay unit 12f. z
First, the LFEch original audio signal is branched into two systems, and the signals of each system are directly input to the synthesizer 13a and the synthesizer 13b, respectively.

In the configuration shown in FIG. 15, first, the configuration of the signal system corresponding to the combination of LFch and RFch is the basic of the headphone system corresponding to the two channels of the left sound source Srcl and the right sound source Scrc shown in FIG. Corresponds to the configuration. For this reason, the signal corresponding to the main audio component (left output channel) of the LFch is output from the synthesizer 13a by the drive unit SPu-L without passing through the filter and delay device. It is trying to obtain a sound with the same signal characteristics as the convolution. Further, the signal corresponding to the LFch sub-sound component (right output channel) is passed through the filter 11b and the delay unit 12b, thereby giving the sub-sound frequency characteristic difference and arrival time difference with respect to the main sound. The sound having the same signal characteristic as that obtained by convolution of the transfer function Hlfr is obtained.
Similarly, the signal corresponding to the main audio component (right output channel) of RFch is output from the synthesizer 13b by the drive unit SPu-R without passing through the filter and delay unit, so that the transfer function Hrfl is convoluted. For the signal corresponding to the RF channel sub audio component (left output channel), the signal corresponding to the RF channel sub audio component (left output channel) is passed through the filter 11a and the delay device 12a, so A frequency characteristic difference and arrival time difference are given, and a sound having a signal characteristic equivalent to that obtained by convolution of the transfer function Hrfl is obtained.

Further, the filter 11d and the delay device 12d provided corresponding to the main audio component (left output channel) of the LSch have a main characteristic of the LFch in order to obtain a signal characteristic equivalent to that of the convolution of the corresponding transfer function Hlsl. Parameters (passband characteristics, delay time) for giving characteristic differences (frequency characteristic differences and arrival time differences) with respect to audio components are set. In other words, if the main audio component of LSch is used as a reference, the main audio component of LFch has a different path to reach the left ear depending on the position of each sound source. This characteristic difference is obtained by the filter 11d and the delay device 12d.
In addition, the filter 11g and the delay device 11g provided corresponding to the LSch sub-sound component (right output channel) have the same LSch in order to obtain a signal characteristic equivalent to the convolution of the corresponding transfer function Hlsr. A parameter for giving a characteristic difference with respect to the main audio component is set.

  Further, the filter 11f and the delay device 11f provided corresponding to the main audio component (right output channel) of the RSch have a main characteristic of the LFch in order to obtain a signal characteristic equivalent to the convolution of the corresponding transfer function Hlsl. A parameter for giving a characteristic difference with respect to the sound component is set. In addition, the filter 11g and the delay device 11g provided corresponding to the LSch sub-sound component (right output channel) have the same LSch in order to obtain a signal characteristic equivalent to the convolution of the corresponding transfer function Hrsr. A parameter for giving a characteristic difference with respect to the main audio component is set.

Further, Cch is branched to a signal system corresponding to the left output channel and the right output channel after passing through the filter 11e and the delay device 12e. Cch is a sound source located in front of the listener M as shown in FIG. For this reason, ideally, the transfer characteristics Hcl and Hcr corresponding to the sounds of the respective systems reaching the left and right ears of the listener M are equal, and the main sounds such as LFch, RFch, LSch, and RSch are used. There is no difference between the component and the sub audio component. In other words, in Cch, there is a substantial difference between the system corresponding to the left ear of the listener M and the system corresponding to the right ear, whichever is treated as the main audio component or the sub audio component. There is nothing.
However, if the main audio components of LFch and RFch are used as a reference, there is a difference in signal characteristic between sound components corresponding to the left and right ears of Cch. Therefore, if this signal characteristic difference is given, transfer characteristics Hcl and Hcr as Cch are obtained, and the sound image localization is realized. The parameters of the filter 11e and the delay device 12e are set so as to give this signal characteristic difference.

Further, as described above with reference to FIG. 14, LFEch has a low directivity compared to the sound of other channels because of its low reproduction frequency band. This also applies to headphone playback. Therefore, the LFEch is directly input to the synthesizers 13a and 13b without being given signal characteristics.
In this way, in the configuration shown in FIG. 15, the transmission characteristics corresponding to the sound component reaching the left ear and the transmission characteristics of the sound component reaching the right ear are convoluted with respect to the audio signals of channels other than LFEch. Are combined, and output from the drive unit SPu-L of the left output channel and the drive unit SPu-R of the right output channel, respectively. Then, when the listener M listens to the sound output in this manner, sound image localization corresponding to the sound source position shown in FIG. 14 is perceived.

By the way, as described above, depending on the headphone reproduction system having the configuration shown in FIG. 15, in principle, it is possible to listen to the virtual sound image localization corresponding to the 5.1ch surround channel configuration. In reality, it has been found that the sound image localization may not be perceived well because it is dilute or unnatural.
One of the main causes is that the audio components for each channel that should reach the left and right ears are electrically synthesized at the audio signal stage using the combiners 13a and 13b. It is done.

The original sound reproduction system as 5.1ch surround is configured to arrange speakers for each channel according to, for example, FIG. 14, and reproduce and output the corresponding channel sound from these speakers. In this case, the left and right ears of the listener M are transmitted to the eardrum after the sound components emitted from the speakers of the respective channels to be reached are synthesized in space.
For example, audio reproduced between channels can be in a state of being out of phase and in phase with each other. In principle, opposite-phase sounds cancel each other out and cannot be heard, and in-phase sounds strengthen each other. It is considered that this phenomenon is rather connected to a rich sound field feeling. However, when such phase-related sounds are electrically synthesized at the stage of the audio signal, they will cancel or intensify each other almost accurately, and this may be an unnatural sound. For example, the sound field may be perceived as not good.

In addition, the great influence of individual differences among actual listeners may be another main cause of poor sound image localization.
The transfer function used in the headphone reproduction system described so far with reference to FIGS. 9 to 15 is called a head-related transfer function, and represents, for example, the transfer characteristic of the sound path from the sound source to the listener's eardrum. It is supposed to be. For this reason, the head-related transfer function includes a characteristic component that is reflected by the human pinna and reaches the eardrum. Actually, there are individual differences in the shape of the human pinna, and it is difficult to set the head-related transfer function corresponding to such differences. Therefore, in setting the head-related transfer function, the pinna shape set as a standard is assumed by an appropriate method. However, the proportion of the characteristics given by the pinna shape in the head-related transfer function is reasonably high. In addition, the actual human pinna shape may differ from person to person, and the individual differences are correspondingly large. For this reason, for example, a listener who has a pinna shape that is quite different from the pinna shape set as a standard will hear a sound far from the sound due to the set transfer function. Sound image localization will be perceived.

  Therefore, the headphone sound reproduction system including the headphone device according to the present embodiment is configured to eliminate the above factors as much as possible and obtain a good virtual sound image localization feeling as described below.

First, FIG. 16 shows a basic acoustic model which is a premise in the headphone reproduction system corresponding to the present embodiment. This figure shows a case where the left sound source Srcl and the right sound source Scrr are set at symmetrical positions in front of the listener M (listening position), as in the case of FIG.
For example, in the acoustic model shown in FIG. 11, the transfer functions Hll, Hrr, Hrr, and Hrl of the sound reaching the left and right ears from the left sound source Srcl and the right sound source Scrr correspond to the sound path from the sound source position to the eardrum. Therefore, the measurement point is assumed to be in the auricle corresponding to the eardrum.
On the other hand, in the present embodiment, the measurement points of the sound reaching the left and right ears from the left sound source Srcl and the right sound source Scrr are shown as spatial measurement ranges P1 and P2 and near the outside of the left and right pinna. The position range in the space is set. In the space measurement ranges P1 and P2, measurement positions corresponding to the respective sound sources are set as shown in FIG. First, in the space measurement range P1, the measurement point Pll of the sound that the left sound source Srcl reaches the left ear and the measurement point Prl of the sound that the right sound source Srcr reaches the left ear are set. In the space measurement range P2, a measurement point Prr for the sound that the right sound source Scrc reaches the right ear and a measurement point Plr for the sound that the left sound source Srcl reaches the left ear are set. Note that the positions of the measurement points with respect to the horizontal direction (horizontal arrangement direction), the vertical direction (height direction), the distance from the auricle, and the like are set as described later with reference to FIG. In the case of configuring, it is determined corresponding to the arrangement position of the drive unit for reproducing and outputting each of the four sounds. That is, these measurement points (Pll, Prl, Prr, Plr) are assumed to be positions on a space where the corresponding sound drive units are arranged. By setting the measurement points in this way, in the present embodiment, the transfer function of the sound reaching the left and right ears from the left sound source Srcl and the right sound source Scrc is up to just before reaching the pinna. It is assumed that it corresponds to the spatial path, and the effect of the pinna is eliminated.
In FIG. 11, the main sound component and the sub sound component that reach the left and right ears from the left sound source Srcl, and the main sound component and the sub sound component that reach the right and left ears from the right sound source Scrc Although expressed as Hll, Hlr, Hrr, and Hrl, respectively, transfer functions from which the influence of the pinna handled in the present embodiment is eliminated as shown in FIG. 16 are expressed as sHll, sHlr, sHrr, and sHrl. I will decide.

Next, FIG. 18 shows a basic configuration corresponding to the acoustic model of FIG. 16 as a configuration example of the audio signal processing system of the headphone acoustic reproduction system of the present embodiment.
In the configuration of FIG. 18, as input signals, the original sound signal Sl corresponding to the original sound emitted from the left sound source Srcl in FIG. 16 and the original sound signal corresponding to the original sound emitted as the right sound source Scrc in FIG. Sr is input.
In addition, the original audio signal S1 is branched into two systems corresponding to the main audio component reaching the left ear from the left sound source Srcl and the sub audio component reaching the right ear, and the system corresponding to the main audio component is By performing reproduction and output by the drive unit SPu-L without particularly performing filter processing and delay processing, it is possible to obtain sound equivalent to that in which the transfer function sHll is convoluted.
In FIG. 12, the transfer function corresponding to the route to reach the left and right ears in the reproduced sound of the main sound component when the sound is reproduced by the headphone device due to the configuration of the housing part including the drive unit. Has been given approximately, and therefore it can be omitted without performing filter processing and delay processing on the audio signal of the system corresponding to the main audio component.
Also in the present embodiment, the system corresponding to the main audio component is given signal characteristics equivalent to the convolution of the transfer function sHll by not performing filtering and delay processing. This is because, in FIG. 12, the audio signal of the system corresponding to the main audio component is not subjected to filter processing and delay processing.
The same applies to a system that outputs the original audio signal Sr from the drive unit SPu-R corresponding to the main audio component of the right sound source Scrc, which will be described later.
The system corresponding to the sub audio component from the left sound source Srcl is reproduced and output by the drive unit SPu-f (L) after passing through the filter 11-f (L) and the delay device 12-f (L). Like that. In the present embodiment, although a transfer function in which the influence of the pinna is eliminated is given, the signal characteristics of the sound measured at an appropriate measurement point reaching the left ear side from one sound source, and the right ear side However, there is still a difference in frequency characteristics and time of arrival due to differences in the sound arrival angle and direction, and the difference in transfer characteristics. It is also expressed as Therefore, depending on the filter 11-f (L) and the delay unit 12-f (L), the transfer function sHlr is convoluted by giving a signal characteristic difference with respect to the main audio component from the left sound source Srcl. The signal characteristic equivalent to is obtained.

Also, the original audio signal Sr is branched into two systems corresponding to the main audio component reaching the right ear from the right sound source Scrc and the sub audio component reaching the left ear, and the system corresponding to the main audio component is Without performing filter processing and delay processing in particular, reproduction and output are performed by the drive unit SPu-R, and an equivalent sound as if the transfer function sHrr is convoluted is obtained.
In addition, the system corresponding to the sub sound component from the right sound source Scrc passes through the filter 11-f (R) and the delay device 12-f (R) to obtain a signal characteristic difference with respect to the main sound component from the right sound source Scrc. And reproduced and output by the drive unit SPu-f (R). As a result, a sound having a signal characteristic equivalent to the convolution of the transfer function sHrl is reproduced.

For example, in the configuration of the headphone playback system according to FIG. 12 described above, there is only one drive unit for each of the left and right output channels, and it corresponds to the sound that reaches the left ear from two sound sources and can be heard. And the audio signal corresponding to the sound that can be heard by reaching the right ear are combined and then output by the drive units SPu-L and SPu-R of the left and right output channels. .
On the other hand, in the present embodiment, the left and right output channels (L, R) are used to output audio signals corresponding to sounds that are supposed to reach the left ear side and the right ear side from the left sound source Srcl and the right sound source Scrc. Rather than combining them individually, they are output from independent drive units. In other words, in the present embodiment, the output channel, that is, the drive unit SPu− is associated with each audio signal corresponding to the sound that is supposed to reach the left ear side and the right ear side from each of the left sound source Srcl and the right sound source Scrc. L is provided. Here, output channels L, R, f (R), and f (L) are shown corresponding to the drive units SPu-L, SPu-R, SPu-f (R), and SPu-f (L). ing.

FIG. 19 schematically shows an example of the arrangement structure of the drive units in the left and right housing portions as an example of the headphone device corresponding to the configuration of the audio signal system shown in FIG.
As shown in this figure, first, in the left housing part 1L of the headphone device, drive units SPu-L and SPu-f (R) are provided, and the sound reproduced by these drive units by the left ear. Can be heard. In the right housing portion 1R, drive units SPu-R and SPu-f (L) are provided so that sounds reproduced by these drive units can be heard by the right ear.
In addition, as the arrangement of the drive unit in the left housing portion 1L, first, the drive unit SPu-L is arranged in correspondence with the position corresponding to the measurement point Pll in FIG. This position is regarded as, for example, a reference position (reference position corresponding to the front-rear direction) that is not biased forward or backward with respect to the ear. The drive unit SPu-f (R) is arranged in front of the drive unit SPu-L, for example, at a position corresponding to the measurement point Prl separated by a predetermined distance difference DS1.
Also in the arrangement of the drive unit in the right housing part 1R, the drive unit SPu-R is arranged in correspondence with the reference position corresponding to the front-rear direction corresponding to the measurement point Prr in FIG. 16 according to the left housing part 1L. In addition, the drive unit SPu-f (L) is disposed at a position corresponding to the measurement point Plr that is separated from the drive unit SPu-R by a distance difference DS1.

In the basic configuration of the headphone playback system as the present embodiment shown in FIG. 18 and FIG. 19, first, for the left sound source Srcl, the main audio component output from the drive unit SPu-L is heard with the left ear, The sub-audio component output from the drive unit SPu-f (L) is heard with the right ear. At this time, since the drive unit SPu-f (L) is located in front of the drive unit SPu-R that is arranged on the basis of the right ear, the sound of this sub-sound component is made to come from the front. Will reach the ear. Thereby, the listener can perceive the sound of the left sound source Srcl as being localized left front.
Similarly, for the right sound source Scrc, the main audio component output from the drive unit SPu-R is heard with the right ear, and the sub audio component output from the drive unit SPu-f (R) with the left ear. It is made to listen. Since the drive unit SPu-f (R) is also located in front of the drive unit SPu-L that is arranged on the left ear side as a standard, the sound of this sub-sound component reaches the ear so that it also comes from the front. In other words, the sound of the right sound source Sccr can also be perceived as being localized to the right front. That is, it is possible to perceive the sound image localization of the left sound source Srcl and the right sound source Srcr.

On the left ear of the listener M, the main sound component from the left sound source Srcl corresponding to the output channel L and the sub sound component from the right sound source Scrc corresponding to the output channel f (R) are left housing part. It will be heard after being synthesized in the space in 1L. Similarly, in the right ear of the listener M, the main sound component from the right sound source Scrc corresponding to the output channel R and the sub sound component from the left sound source Srcl corresponding to the output channel f (L) are After being synthesized in the space in the housing part 1R, it reaches and can be heard.
In this way, in the headphone device of the present embodiment, the sound of the output channel that is supposed to reach each ear from the sound source is reproduced by each independent drive unit and then synthesized in a space close to the left and right ears. ing. For this reason, for example, when the audio signal corresponding to the sound that is supposed to reach each ear from the sound source is electrically synthesized and then output as the audio, the signals of opposite phase and in-phase cancel each other exactly. Or the phenomenon of strengthening each other. This makes it possible to obtain a better sound field feeling.

Further, as in the present embodiment, the sound for each output channel that is supposed to reach each ear from the sound source is synthesized in space and then reaches the ear. It can be said that the emitted sound reaches the eardrum after being synthesized in space and then reflected by the auricle.
Therefore, as in the present embodiment, transfer characteristics (frequency characteristics, delay time difference) excluding the influence of the pinna are applied to the audio signal for each output channel that is supposed to reach each ear from the sound source. For example, the characteristics that change corresponding to the pinna can be formed by the pinna of the actual listener. This means that it is possible to feel a good sound image localization regardless of individual differences such as the shape of the pinna.
In this way, the headphone playback system according to the present embodiment is configured so that more people can obtain a sound image localization feeling that is better than before.

By the way, the delay times of the delay units 12-f (R) and 12-f (L) shown in FIG. 18 are as follows. An arrival time difference determined according to the distance until the component reaches and the distance until the sub audio component reaches the other ear is given to the audio signal of the sub audio component. For example, in the case of the configuration shown in FIG. 12, the sound of the main sound component of one sound source and the sound of the sub sound component of the other sound source are synthesized at the stage of the sound signal. The best mode is to give the time difference as it is.
However, in the present embodiment, as shown in FIG. 19, for example, in the case of the left housing portion 1L, the physical distance DS1 is given for the arrangement positions of the drive unit SPu-L and the drive unit SPu-f (R). Therefore, it is inevitably output from the drive unit SPu-f (R) with respect to the time that the main sound of the left sound source Srcl output from the drive unit SPu-L reaches the left ear according to the distance DS1. A delay in the time for the sub sound of the right sound source Sccr to reach the left ear will occur. Therefore, in order to obtain the arrival time difference in the best mode, depending on the distance from the left sound source Srcl until the main audio component reaches the left ear and the distance until the sub audio component reaches the right ear The time obtained by subtracting the delay time corresponding to the distance DS1 from the determined arrival time difference should be set in the delay device 12-f (R).

  Subsequently, a configuration example of a headphone sound reproduction system corresponding to multi-channel based on the basic configuration described with reference to FIGS. 16 to 19 will be described. In this case as well, the multi-channel configuration is taken as an example in the 5.1ch surround standard.

First, FIG. 20 shows a 5.1 ch surround acoustic model corresponding to the present embodiment.
Also in the acoustic model shown in this figure, speakers SP-LF, SP-C, SP- are used as sound sources corresponding to LFch, Cch, RFch, LSch, RSch, and LFEch, for example, as shown in FIG. RF, SP-LS, SP-RS, and SP-LFE are shown. Also, the arrangement of these speakers is the same as in FIG.
However, in this embodiment, when configuring a headphone sound reproduction system that supports 5.1ch surround, transmission of each sound that reaches the left and right ears of the listener M from the sound source (speaker) of each channel. As described with reference to FIG. 16, the function is a function from which the influence of the pinna is excluded. In other words, in the vicinity of the outside of the left and right pinna, the measurement is performed at the measurement points set in the space measurement ranges P1 and P2, which is a set range of measurement points in the space where the drive unit corresponding to each sound is located. The transfer function of sound from each sound source is used.
An example of setting measurement points in the space measurement ranges P1 and P2 in this case is shown in FIG. First, in the space measurement range P1 corresponding to the left ear, the measurement point Pcl of the sound arriving from the SP-C is set in front of the measurement point Plfl corresponding to the sound arriving from the speaker SP-LF. Further ahead, the measurement point Prfl of the sound reaching from the speaker SP-RF is set. In addition, a measurement point Plsl of sound arriving from the speaker SP-LS is set behind the reference measurement point Plfl, and a measurement point Prsl of sound arriving from the speaker SP-RS is set further behind. is doing.
In the space measurement range P2 corresponding to the right ear, the measurement point Pcr of the sound arriving from the SP-C is set in front of the measurement point Prfr corresponding to the sound arriving from the speaker SP-RF. Further ahead, a measurement point Plfr for a sound reaching from the speaker SP-LF is set. In addition, a measurement point Prsr of sound arriving from the speaker SP-RS is set behind the reference measurement point Prfr, and a measurement point Plsr of sound arriving from the speaker SP-RS is set further behind. is doing.
Here, as shown in FIG. 20, the transfer function corresponding to each sound is expressed as follows.
sHlfl: Transfer function of the path from the speaker SP-LF to the left ear side (measurement point Plfl) as the main audio component
sHlfr: Transfer function of the path from the speaker SP-LF to the right ear side (measurement point Plfr) as a secondary audio component
sHcl: transfer function of the path from the speaker SP-C to the left ear side (measurement point Pcl) as the main sound / sub sound component
sHcr: transfer function of a path from the speaker SP-C to the right ear side (measurement point Pcr) as a sub-sound / main sound component
sHrfl: transfer function of the path from the speaker SP-RF to the left ear side (measurement point Prfl) as a sub-speech component
sHrfr: transfer function of the path from the speaker SP-RF to the right ear side (measurement point Prfr) as the main audio component
sHlsl: transfer function of the path from the speaker SP-LS to the left ear side (measurement point Plsl) as the main audio component
sHlsr: transfer function of the path from the speaker SP-LS to the right ear side (measurement point Plsr) as a secondary audio component
sHrsl: transfer function of the path from the speaker SP-RS to the left ear side (measurement point Prsl) as a sub audio component
sHrsr: transfer function of the path from the speaker SP-RS to the right ear side (measurement point Prsr) as the main audio component

Next, a configuration example of a signal system corresponding to 5.1ch surround will be described with reference to FIG. 22 as the headphone sound reproduction system of the present embodiment.
First, in this configuration, for each of the six channels (LFch, Cch, RFch, LSch, RSch, LFEch) constituting 5.1ch surround, 12 outputs corresponding to the sound components reaching the left ear and the right ear, respectively. Channel (LF, f (LF), RF, f (RF), C (L), C (R) LS, f (LS), RS, f (RS), LFE (L), LFE (R)) It is supposed to be provided. In addition, the drive units also correspond to each of these output channels, and drive units SPu-LF, SPu-f (LF), SPu-RF, SPu-f (RF), SPu-C (L), SPu-C ( R), SPu-LS, SPu-f (LS), SPu-RS, SPu-f (RS), SPu-LFE (L), SPu-LFE (R) are provided.
In addition, a signal system for each audio signal of each channel as 5.1ch surround is formed as follows.

  In FIG. 22, a total of seven filters 11 and a total of five delay devices 12 are shown. Although all of these filters 11 and delay devices 12 may be provided, in this embodiment, the filter 11 and the delay device 11 indicated by broken lines among them are described later. Can be omitted. Therefore, in the description of the signal system of FIG. 22 here, the description is made assuming that the filter 11 and the delay device 12 indicated by the broken lines are omitted.

  First, in the configuration of the signal system shown in FIG. 22, the basic configuration corresponding to FIG. 18 is provided as a signal system corresponding to LFch and RFch. That is, as the correspondence relationship between the channels in FIGS. 18 and 22, on the input source side, the left sound source Srcl and the right sound source Scrr in FIG. 18 correspond to LFch and RFch in FIG. 18 L, f (L), R, and f (R) correspond to LF, f (LF), RF, and f (RF), respectively.

In accordance with the above-described correspondence, first, the original LFch audio signal is branched into two systems, and one system is directly subjected to the drive unit SPu− without being subjected to filter processing and delay processing as main audio components. It is input to the LF. It is assumed that the transfer function sHlfl is given by this system. The other system passes through a filter 11-f (LF) and a delay device 12-f (LF), and is given a signal characteristic of a difference with respect to the main audio component, so that the drive unit SPu-f (LF ), So that the given sound is reproduced such that the transfer function sHlfr is convoluted.
Also, the RFch original audio signal, which is the sound source that is the left and right target for LFch, is also branched into two systems of the main audio component and the sub audio component, and the main audio component system is subjected to filter processing and delay processing. Without being directly input to the drive unit SPu-RF, the transfer function sHrfr is given. Further, the sub audio component system passes through the filter 11-f (RF) and the delay device 12-f (RF), so that the signal characteristic of the difference with respect to the main audio component is given, and the drive unit SPu-f (LF) is input, so that the sound given the transfer function sHrfl is reproduced.
Then, the remaining LSch, RSch, Cch, and LFEch signal systems are provided for the basic components as described below.

The original audio signal of Lsch is directly input to the drive unit SPu-LS without passing through filter processing or the like for the main audio component, thereby reproducing the audio given the transfer function sHlsl. . Further, with respect to the sub audio component, the transfer function sHlsr is given by being input to the drive unit SPu-f (LS) via the filter 11-f (LS) in order to give a signal characteristic difference with respect to the main audio component. Get playback audio.
In addition, the original audio signal of RSch that is symmetric with respect to LSch is directly input to the drive unit SPu-RS without passing through filter processing or the like for the main audio component, which gives the transfer function sHrsr. So that the recorded audio is played. Further, the sub-sound component is given a transfer function sHrsl by being input to the drive unit SPu-f (RS) via the filter 11-f (RS) in order to give a signal characteristic difference with respect to the main sound component. Get playback audio.

  In addition, the Cch original audio signal is also split into two, so that one system is directly input to the drive unit SPu-C (L) and the other system is directly input to the drive unit SPu-C (R). I try to let them. As described above with reference to FIG. 15, Cch is a sound source that is localized in front of the listener M. Therefore, the Cch is positioned at the positions corresponding to the left and right ears of the listener M (measurement points P <b> 1 and P <b> 2). Therefore, it is assumed that there is no difference in signal characteristics corresponding to the main audio component and the sub audio component, and the transfer functions sHcl and sHcr of each sound are equivalent. Therefore, as described above, the same Cch original sound signal is input to the drive units SPu-C (R) and SPu-C (L) corresponding to the left and right housing portions.

  In addition, the directivity of the LFEch sound is dull as described with reference to FIG. Therefore, assuming that the same sound is output from the left and right housing parts, the LFEch original audio signal is branched into two systems, and the signals of each system are The drive units SPu-LFE (L) and SPu-LFE (R) corresponding to the housing portion are directly input.

Here, as the sound reproduction characteristics of the twelve drive units shown in FIG. 22, the same sound reproduction characteristics may be used. If the sound reproduction characteristics of the drive unit are the same, the design of the signal processing system including the pass band characteristics of the filter 11 becomes easy. However, the drive units SPu-LFE (L) and SPu-LFE (R) corresponding to LFEch are required to reproduce a considerably lower band compared to the frequency band to be reproduced by other drive units. The sound reproduction characteristics may be suitable for such low-frequency reproduction.
Incidentally, as an actual example of the present embodiment, for example, 10 drive units other than LFEch adopt the same sound reproduction characteristics, and two drive units corresponding to LFEch have a larger diameter. A sound reproduction characteristic is used for bass reproduction.

Next, an arrangement example of the drive unit in the headphone device corresponding to the configuration of the signal system shown in FIG. 22 will be described with reference to FIGS.
First, as shown in FIGS. 23 and 24, in the left housing portion 1L of the headphone device, the drive unit SPu-f ( RF), SPu-C (L), SPu-LF, SPu-LS, and SPu-f (RS). In this case, the drive unit SPu-LFE (L) is arranged below the position where the drive units SPu-C (L) and SPu-LF are arranged.
Further, in the right housing portion 1R of the headphone device, the drive units SPu-f (LF), SPu-C (R), SPu are arranged so that the center position of the sounding portion is along the horizontal imaginary line H from the front to the rear. -RF, SPu-RS, SPu-f (LS) are arranged. Further, the drive unit SPu-LFE (R) is arranged below the position where the drive units SPu-C (R) and SPu-RF are arranged.

In the arrangement mode described above, first, drive units corresponding to channels other than LFEch are arranged along the same horizontal imaginary line H in the left and right housing portions. This arrangement mode corresponds to the arrangement positional relationship of each channel sound source (speaker) as 5.1ch surround.
That is, for example, on the left housing portion 1L side, the drive unit SPu-LS corresponding to the main audio component of LSch is arranged behind the drive unit SPu-LF corresponding to the main audio component of LFch. Further, a drive unit SPu-C (L) corresponding to Cch is arranged in front of the drive unit SPu-LF. Thus, it can be seen that the drive unit corresponding to the main sound component and the sound of the channel corresponding to the main sound component is arranged corresponding to the position of the channel sound source. Of the drive units corresponding to the sub audio component, the drive unit SPu-f (RF) corresponding to the front sound source is arranged on the front side with respect to the drive unit SPu-LF at the reference position, and the rear The drive unit SPu-f (RS) corresponding to the sound source is arranged behind the reference position.
On the right housing part 1R side, the drive units SPu-f (RF), SPu-C (R), SPu-LF, SPu-LS, SPu- are arranged in a symmetrical relationship with the left housing part 1L. Therefore, the drive unit corresponding to the main audio component is also arranged corresponding to the position of the channel sound source on the right housing part 1R side, and as a sub audio component. The drive unit SPu-f (LF) corresponding to the front sound source is arranged in front of the reference position, and the drive unit SPu-f (LS) corresponding to the rear sound source is arranged in rear of the reference position. It has become.

  In this case, as described above, the arrangement positions of the drive units SPu-LF and SPu-RF among the drive units arranged in the left and right housing portions are used as references. That is, for the drive units SPu-LF and SPu-RF, positions where the output sound reaches the left and right ears and directions are set so as not to be biased forward or backward. This position is equivalent to the arrangement of the left and right drive units when a headphone device is configured as a normal L, R stereo, for example. In addition, the positional relationship in the front-rear direction for other drive units is set.

In addition, since the drive units SPu-f (RF) and SPu-f (LF) are in front of the reference positions in the left and right housing parts, the sound images as LFch and RFch are localized at appropriate positions in the front. The sound that can be heard is as described above with reference to FIG.
Further, depending on the fact that the drive units SPu-f (LF) and SPu-f (RF) are located behind the reference position in each of the left and right housing parts, the drive units SPu-f (LF) and SPu-f (RF) are located at appropriate positions on the rear side in accordance with the description of FIG. The sound image is localized and can be heard.
Then, the sound of Cch and LFEch is spatially synthesized in the housing portion together with the sound of LF, RF, LSch, and RSch, and reaches the left and right ears. As a result, the listener can clearly feel the sound image localization by the sound source position corresponding to the channel configuration shown in FIG. 20, for example.
It can be said that the arrangement of drive units corresponding to channels other than LFEch follows, for example, the arrangement pattern of the sound sources (speakers) of the channel in the acoustic model (listening environment model) shown in FIG. That is, in the arrangement of the speakers in FIG. 20, first, with respect to the left ear, the left ear is arranged in the order of the speakers SP-RF, SP-C, SP-LF, SP-LS, and SP-RS from the front side to the rear side. It can be seen as surrounding. The arrangement of the drive units in the left housing part 1L also corresponds to the winding order of the speakers, from the front to the rear, the drive units SPu-f (RF), SPu-C (L), SPu-LF, SPu-LS, SPu-f. They are arranged in the order of (RF).
Similarly, with respect to the right ear, it is assumed that the speakers SP-LF, SP-C, SP-RF, SP-LS, and SP-RS are surrounded in this order from the front side to the rear side, symmetrically with the left ear. I can see it. In the right housing portion 1R, in correspondence with the winding order of the speakers, the drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, SPu-f (LF) are arranged in this order. Has been placed.

Further, according to FIG. 23, in each housing portion, five drive units ([SPu-f (RF), SPu-C (L), SPu-LF) corresponding to other than the LFEch arranged along the virtual line H are provided. , SPu-LS, SPu-f (RF)] [drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, SPu-f (LF)], respectively. The angle is given along a curved surface that surrounds the ear, rather than being arranged in a plane, so that, for example, the arrangement position relationship of the drive units is closer to the sound source position in the 5.1ch surround channel configuration. The sound image localization feeling is made clearer.
As described above, the mounting angle and the like when the drive unit is arranged in a curved surface may be set by verifying the sense of sound image localization actually obtained, etc. Thus, a setting in which the sound axis is directed as much as possible with respect to a certain position (voice arrival point Ap) determined as described above is one of preferable modes.

By the way, by arranging the drive unit along the front-rear direction of the listener as shown in FIG. 24, the following operation can be obtained.
For example, in the left housing portion 1L, when attention is paid to the positional relationship between the drive unit SPu-f (RF) corresponding to the sub-audio component of RFch and the drive unit SPu-LF corresponding to the main audio component of LFch, On the other hand, the drive unit SPu-f (RF) is located farther from the drive unit SPu-LF.
This means, for example, that the distance DS1 described above with reference to FIG. 19 exists between the drive unit SPu-f (RF) for the drive unit SPu-LF. Therefore, a time difference that the time for the sound to reach the left ear from the drive unit SPu-f (RF) is longer than the time for the sound to reach the left ear from the drive unit SPu-LF. The sound arrival time to the ear is the same for the drive unit SPu-LF and the symmetrical drive unit SPu-RF. As a signal characteristic of the sub audio component, it is necessary to give an arrival time difference with respect to the main audio component. From the above, this arrival time difference is determined by the position between the drive unit SPu-f (RF) and the drive unit SPu-L. By the relationship, you can earn. Thus, as will be described later, in the present embodiment, it is possible to omit a delay unit in a system for outputting sound by the drive unit SPu-f (RF), and a simple signal processing system configuration can be realized. It is.
For the same reason, the drive unit SPu-f (LF) in the right housing portion 1R is also arranged with the same positional relationship as the drive unit SPu-f (RF). The drive unit SPu-f (RS) in the left housing part 1L is also arranged behind the drive unit SPu-LS. Similarly, the drive unit SPu-f (LS) in the right housing part 1R is also from the drive unit SPu-RS. Is also arranged rearward.

  Note that the measurement points in the space measurement ranges P1 and P2 previously shown in FIG. 21 are set corresponding to the spatial arrangement positions of the drive units shown in FIGS. That is, the measurement points Prfl, Pcl, Plfl, Plsl, Prsl in the space measurement range P1 corresponding to the left ear are respectively drive units SPu-f (RF), SPu-C (L), SPu- in the left housing portion 1L. It should be set in consideration of correspondence with the arrangement positions of LF, SPu-LS, and SPu-f (RS). Similarly, the measurement points Plfr, Pcr, Prfr, Prsr, Plsr in the space measurement range P2 corresponding to the right ear are respectively drive units SPu-f (LF), SPu-C (R), It should be set in consideration of the correspondence with the arrangement positions of SPu-RF, SPu-RS, and SPu-f (LS).

FIG. 25 shows a modification of the arrangement of the drive units in the housing part. In this figure, the same parts as those in FIG.
In FIG. 25, first, among the five drive units corresponding to channels other than LFEch provided in the left housing portion 1L, the drive units SPu-f (RF), SPu-C (L), and SPu-LF are shown in FIG. 24, the drive units SPu-LS and SPu-f (RS) are arranged along a virtual horizontal line H similar to that of the virtual horizontal line Hu. It is arranged along the top. Similarly, also in the right housing part 1R, the drive units SPu-f (LF), SPu-C (R), and SPu-RF are arranged along the virtual horizontal line H, and the drive units SPu-RS, SPu-f ( LS) is arranged along the virtual horizontal line Hu.
That is, in the 5.1ch surround channel configuration, the drive units corresponding to the main audio component and the sub audio component having the sound source of LSch and RSch that are positioned relative to the listening position are positioned higher than the drive units of other channels. Is set to be.
For example, in the case where sound reproduction is performed by a speaker system that supports a multi-channel configuration such as an actual 5.1 channel surround, a speaker of a channel arranged at a position behind the listening position is set to the front with respect to the listening position. It is empirically known that a good sense of sound image localization can be obtained when installed at a position slightly higher than the speaker of the channel arranged at a certain position. The arrangement example of the drive unit shown in FIG. 25 is an application of this, and as a result, a better sound field can be obtained also in the headphone device of the present embodiment.
As shown in FIG. 25, when the arrangement position of the drive unit is changed in the height direction, the position in the height direction for each measurement point in the space measurement ranges P1 and P2 should be changed and set. It will be.

  By the way, as described above, the description of FIG. 22 is based on the assumption that the filter 11, the delay device 12, and the like indicated by the broken lines are omitted. However, in the signal system shown in FIG. 22, the filter 11 for providing a frequency characteristic difference with the main sound is provided in the sub sound system in LFch, RFch, LSch, and RSch without being omitted. The filter 11 can be constituted by a digital filter, for example, but an analog filter is used as the filter 11 in consideration of the simplification and cost reduction of the signal processing system as much as possible. It is also possible.

FIG. 26 shows a configuration example of the filter 11 using an analog circuit.
In this figure, first, an inductor L1 is inserted in series at the first stage where a signal is input, and filter sections 11a, 11b, and 11c are sequentially connected to a subsequent stage of the inductor L1. It is supposed to be. The filter unit 11a is formed by connecting a series circuit including an inductor L2, a resistor R2, and a capacitor C2 and a parallel circuit including an inductor L3, a resistor R3, and a capacitor C3 as illustrated. The filter unit 11b is formed by connecting a series circuit including an inductor L4, a resistor R4, and a capacitor C4 and a parallel circuit including an inductor L5, a resistor R5, and a capacitor C5 as illustrated. The filter unit 11c is formed by connecting a parallel circuit including an inductor L6 and a resistor R6 and a series circuit including a resistor R7 and a capacitor C7 as illustrated.
FIG. 27 shows an example of the frequency characteristic of the sub-voice when the frequency characteristic of the main voice is set as a standard flat characteristic. As shown in the characteristic part A, the frequency characteristic of the sub-audio firstly, the voltage (amplitude) gradually decreases as the frequency range changes from low to high, and then the characteristic part B , C, a dip occurs at two certain frequency points in the mid-range. In a band higher than this, as shown by the characteristic portion D, the voltage gradually decreases.
The filter 11 in FIG. 26 inputs an audio signal (original audio signal) having a characteristic corresponding to the main audio component and gives the signal characteristic shown in FIG. 27. The characteristic of the characteristic portion D is provided by the inductor L1. The characteristic of the characteristic part B is given by the filter part 11a, the characteristic of the characteristic part C is given by the filter part 11b, and the characteristic of the characteristic part A is given by the filter part 11c.

  The configuration example of the filter 11 as an analog circuit shown in FIG. 26 is merely an example. For example, if the characteristics shown in FIG. 27 are obtained within a practically allowable range, other The circuit configuration may be adopted.

Further, in the case of configuring a headphone sound reproduction system that supports 5.1ch surround, strictly speaking, as described above with reference to FIG. It is necessary to obtain a sound in which an appropriate transfer function is convoluted by giving a difference in signal characteristics of sounds of other channels (Cch, LSch, RSch) with respect to the channel.
However, in the configuration of FIG. 22, the filters for the main audio component are omitted for Cch, LSch, and RSch. That is, the filter that gives the signal characteristic difference with respect to the LFch and RFch sounds is omitted.
This is also because the drive unit corresponding to each output channel is individually arranged in the housing portion in the present embodiment. That is, in the present embodiment, as described above with reference to FIG. 23, for example, the drive units are arranged according to the arrangement positional relationship corresponding to the sound source (speaker) position of each channel forming 5.1ch surround. Yes. This is a major factor in obtaining good sound image localization. That is, an operation equivalent to giving a signal characteristic difference with respect to the sound of LFch and RFch, for example, is obtained by the positional relationship of the drive units in the housing. 22, the Cch, LSch, and RSch filters 11-C, 11-LS, and 11-RS indicated by broken lines are omitted as actual circuits. For this reason, a configuration equivalent to inserting these filters 11 is obtained.

  Further, for example, under the basic configuration shown in FIG. 18, a delay device 12 is provided together with the filter 11 for the sub audio component system. As described above, the delay unit 12 is different from the time until the main sound component reaches the one ear from the sound source until the sub sound component reaches the other ear (here, “main / sub sound”). The main purpose is to create a difference between arrival times). However, the configuration as the simple signal processing system shown in FIG. 22 shows a form in which the delay unit 12 is omitted for each of the sub-audio systems of LFch, RFch, LSch, and RSch. In other words, in the headphone sound reproduction system of the present embodiment, a corresponding delay time is obtained by the system itself that outputs the sub audio component as described below, and for this reason, the delay device can be omitted. .

First, the system to output the sub audio component is provided with the filter 11 for providing a frequency characteristic difference with respect to the main audio component as described above. As a general matter, a phase difference with respect to the input signal is produced by the signal passing through the filter. This phase difference can be viewed as a signal delay. That is, the audio signal of the sub audio component is given a delay time by passing through the filter 11.
Further, as shown in FIGS. 19, 23, etc., the drive unit to output the secondary audio is the drive unit (SPu-L, SPu-R) (SPu-LF, SPu-RF) of the reference channel in the housing portion. ) With a certain distance. Thus, for example, taking the right housing portion 1R side of FIG. 23 as an example, the drive unit SPu-f (LF corresponding to the sub audio component with respect to the sound arrival time from the reference drive unit SPu-RF to the right ear is used. ), The arrival time of each sound from the SPu-f (LS) to the right ear is the distance from the arrangement position of the drive unit SPu-RF to the arrangement position of the drive units SPu-f (LF) and SPu-f (LS). It will have a corresponding delay time. Here, if the arrival time of the sound from the drive unit SPu-RF to the right ear is equivalent to the arrival time of the sound from the drive unit SPu-RF to the left ear on the left housing part 1L side, the delay time described above. That is, the arrival time difference between the main and sub sound sources. Therefore, if the delay time obtained in accordance with the arrangement position of the drive unit in this way falls within an error within an allowable range with respect to the delay time to be actually set by the delay device 12, the delay device in that system is used. Thus, 12 can be omitted.

In FIG. 22, the Cch system is also shown in a form in which the delay device 12-C is omitted as indicated by a broken line. The Cch system can be handled as a signal characteristic difference between sounds that reach the left and right ears, but for example, as a signal characteristic difference with respect to the main audio component of the reference LFch and RFch, LFch and RFch A difference between each time when sound arrives at the left and right ears from the sound source is different from each time when sound arrives at the left and right ears from the Cch sound source. Note that the time difference between sounds that reach the same one ear from the sound sources of different channels in this way is called “interchannel arrival time difference”. The delay unit 12-C is originally for accurately generating the inter-channel arrival time difference between Cch, LFch, and RFch, but this delay unit 12-C can be omitted. This is also possible depending on the arrangement position of the drive unit.
That is, as shown in FIG. 23, the drive units SPu-C (L) and SPu-C (R) corresponding to the left and right Cch are located in front of the drive units SPu-LF and SPu-RF, respectively. They are arranged at a certain distance from each other. As a result, on the left housing portion 1L side, a time difference is generated with respect to the sound reaching the left ear from each of the drive unit SPu-LF and the drive unit SPu-C (L). That is, it can be considered that an inter-channel arrival time difference between Cch and LFch has occurred. Similarly, on the right housing part 1R side, it is assumed that the arrival time difference between channels between Cch and LFch is caused by the difference in time from the drive unit SPu-RF and the drive unit SPu-C (R) to the right ear. be able to. Thereby, even if the delay unit 12-C is omitted, it is possible to obtain signal characteristics equivalent to the provision of the delay unit 12-C.

Next, an actual example of the headphone device of the present embodiment to which the arrangement of the drive unit described so far is applied will be described.
FIG. 1 shows an example of an outer shape that can be employed in the headphone device of the present embodiment.
The headphone device 100 shown in this figure is a so-called overhead band type, and a right housing portion 1R and a left housing portion 1L are attached to both sides of the headband 2, respectively. In addition, ear pads 3R and 3L using a cushion material called an ear pad are attached to the inner edge portions of the right housing portion 1R and the left housing portion 1L, respectively.
The user puts the headband device 100 on the head, and in this state, wears the headphone device 100 so that the ear pads 3R and 3L of the right housing portion 3R and the left housing portion 3L are in contact with the right and left ears. .

Next, an example in which the drive unit is actually attached to the inner wall portion of the housing portion of the headphone device 100 according to the arrangement of the drive unit described so far (example of drive unit attachment) will be described.
It should be noted that the LFEch has a very low degree of freedom in setting the arrangement position of the drive unit of the LFEch because the sense of localization of the sound is sparse. Therefore, in the following description, the drive unit arrangement corresponding to channels other than LFEch will be mainly referred to. In the following explanation of the drive unit mounting example, the arrangement of the drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, SPu-f (LS) in the right housing portion 1R is described. The left housing portion 1L is also symmetrical with respect to the right housing portion 1R side so that the drive units SPu-f (RF), SPu-C (L), SPu-LF are used. , SPu-LS and SPu-f (RF) are arranged.

FIG. 2 shows a first example as a drive unit mounting example. 2A is a view of the drive unit arrangement on the right housing part 1R side as seen from the plane direction, and FIG. 2B is a perspective view of the drive unit arrangement seen from the inside of the housing part 2R of the right housing part 1R. is there.
Note that the drive unit mounting position in this figure is as shown in FIG. 24 in the drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, SPu-f on the horizontal virtual line H. (LS) is arranged, and the drive unit SPu-LFE (R) is arranged below the horizontal imaginary line H. This also applies to the drive unit arrangements in the second and subsequent examples.
Further, in FIG. 2A and FIG. 3A described later, a circumference O having a predetermined radius size is provided with respect to the right housing portion 1R so that a difference in the arrangement position of the drive unit can be easily understood visually. And a straight line L having a diameter of the circumference O is indicated by a broken line.

As shown in FIGS. 2A and 2B, in this case, the drive units SPu-f (LF), SPu-C (R), SPu are formed on the surface of the housing inner wall 4R having a bowl-shaped curved shape. -RF, SPu-RS, SPu-f (LS) diaphragm (opening) cover portion (diaphragm cover cvr) is attached so as to be exposed. At this time, the mounting direction of each drive unit is adjusted so that the sound axis thereof faces the voice arrival point Ap set corresponding to a predetermined position in the right ear. The setting of the voice arrival point Ap will be described later.
The arrangement order of the drive units along the front-rear direction is the same as the arrangement position described so far with reference to FIG. That is, the drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, and SPu-f (LS) are arranged in this order from the front to the rear of the right housing portion 1R. The arrangement order of the drive units reflects the positional relationship (for example, see FIG. 14) of the sound sources (speakers) shown in the ITU recommendation (ITU-R BS.775-1), for example. This is the basic ordering sequence.

By the way, in the first example of the drive unit mounting example, the housing inner wall portion 4R to which the drive unit is mounted has a bowl-shaped curved surface. For this reason, in a state where the headphone device according to the first example is mounted on the head, an environment is formed in which the parabolic shape of the inner wall portion 4R of the housing just reflects the sound intensively in the direction of the ear hole. .
Then, for example, when sound is actually emitted from each drive unit, reflection is repeated in the space formed between the inner wall portion 4R of the housing and the head, and finally it is concentrated in the direction of the ear canal May occur. When such a phenomenon occurs, for example, the occurrence of unnecessary reverberation increases, and an unnatural reverberation may be felt in the sense of hearing.
In particular, as in this embodiment, when a relatively large number of drive units are provided in one housing part so as to be arranged substantially in the front-rear direction, it is necessary to secure an area enough to mount all the drive units. Although the area of the housing inner wall portion 4R tends to be increased, the volume of the space formed by the housing inner wall portion 4R is also increased. This is a factor that facilitates the generation of the above-described unnecessary reverberation.

Therefore, as a countermeasure for the above reverberation, FIG. 3 shows a second example of the drive unit mounting example. In this figure, the same parts as those in FIG.
In the second example, as shown in FIGS. 3A and 3B, the inner wall portion 4R of the housing is formed in a shape that can be seen as a concave polyhedron as a whole. The drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, and SPu-f (LS) are each a predetermined surface (or a plurality of surfaces) in the housing inner wall portion 4R having a concave polyhedron shape. However, at this time, the respective surfaces to which the drive unit is to be attached are the drive units SPu-f (LF), SPu-C as understood from FIG. (R), SPu-RF, SPu-RS, and SPu-f (LS) are each determined to have an inclination of the surface or a position so that each sound axis faces the voice arrival point Ap.

  By making the housing inner wall portion 4R into a polyhedral structure in this way, the sound (sound wave) emitted from the drive unit is reflected (randomly reflected) in a random direction within the space of the housing inner wall portion 4R. As in the case where the inner wall portion 4R has a parabolic shape, it is possible to avoid a phenomenon that the light is concentrated and reflected at the position of the ear hole. Thereby, generation | occurrence | production of an unnecessary reverberation is suppressed significantly and it can prevent the unnatural reverberation feeling from arising.

Further, two examples configured to diffusely reflect sound based on the second example are shown in FIGS. 4 and 5 as a third example and a fourth example of the drive unit mounting example. 4 and 5, the same parts as those in FIG.
First, in FIG. 5 as a third example, the columnar body assembly member 7 is attached to the surface of the housing inner wall portion 4R of the aspect shown in FIG. The columnar assembly member 7 is formed by collecting, for example, an appropriate number of rectangular columns having a predetermined quadrangular size cut into an appropriate length and bonding them together at the side surface portions. For this reason, the columnar body assembly members 7 have different overall shapes and sizes. Then, the columnar body assembly member 7 is appropriately attached and fixed to the surface of the housing inner wall portion 4R having a concave polyhedron shape.
In such a structure, the irregular reflection of the sound emitted from the drive unit is further finely promoted by the columnar body assembly member 7, and a more remarkable suppression effect on the occurrence of unnecessary reverberation can be expected. become.
In addition, resin can be used for the material of the columnar body assembly member 7.

Further, in FIG. 5 as the fourth example, a fragment member 8 is attached in place of the columnar body assembly member 7.
The fragment member 8 is formed, for example, by appropriately crushing resin, stone, or the like. The fragment member 8 is appropriately disposed and fixed to the surface of the housing inner wall portion 4R of the concave polyhedron.
Even in this case, similarly to the third example, the diffuse reflection of the sound emitted from the drive unit is further finely promoted by the fragment member 8, and more effective suppression of unnecessary reverberation can be expected.

  In addition, although it has been described that resin can be used for the columnar body assembly member 7 and resin or stone can be used for the fragment member 8, materials of other materials may be used. However, the inventor of the present application has confirmed that the use of a material having a high sound absorbing effect is not preferable because the required reverberation is suppressed. Therefore, it is preferable that the columnar body assembly member 7 and the fragment member 8 are made of a material having a sound absorption coefficient that is not more than a certain level (reflectance is not less than a certain value) to the extent that necessary reverberation remains. From this point of view, it is also appropriate to employ a material having a sound absorption coefficient of a certain value or less, such as resin, for the housing inner wall 4R itself used in the first to fourth examples.

FIGS. 6A, 6B, and 6C show the reverberation characteristics in the right housing portion 1R that is manufactured corresponding to the first example, the second example, and the third example of the drive unit arrangement of the present embodiment, respectively. Show. In FIGS. 6A, 6B, and 6C, the vertical axis represents the level of reverberation and the horizontal axis represents time.
For example, the reverberation characteristics are observed at the voice arrival point Ap corresponding to the right ear in an environment equivalent to the case where the right housing portion 1R is addressed to the human right ear. Is. In addition, the reverberation sound observed here is for the sound emitted from the drive unit SPu-RF. Similar characteristics can be obtained for the sound emitted from the remaining drive units.

First, comparing FIG. 6A corresponding to the first example and FIG. 6B corresponding to the second example, the reverberation sound level is reduced by about 10 db in the time after about 60 msec. This indicates that the reverberant sound unnecessary for hearing is suppressed.
Further, comparing FIG. 6B corresponding to the second example and FIG. 6C corresponding to the third example, in the time after about 260 msec, in FIG. A slight excess is shown in FIG. 6 (c), which is suppressed until it is within approximately 10 dB. For example, the decrease in the reverberation sound level in the time after the vicinity of 260 msec greatly contributes to suppressing reverberation that is uncomfortable on hearing. In the fourth example shown in FIG. 5, the same characteristics as in FIG. 6C are obtained.
Thus, it has been confirmed by actual measurement that unnecessary reverberation is weakened in the configuration based on the second example. In addition, when the sound is irregularly reflected in this way, for example, it is possible to suppress a phenomenon in which only a sound having a specific frequency is emphasized and heard.
Further, when drive units are arranged on the same surface, it is considered that cross modulation occurs due to pressure fluctuations due to the density of sound waves generated by adjacent drive units, which may degrade the sound. However, in the configuration based on the second example of the drive unit arrangement of the present embodiment, since the drive units can be arranged on different surfaces in the polyhedral structure, the above-described cross modulation is less likely to occur.

By the way, the omission of the delay circuit by the setting of the inter-channel arrival time difference described above with reference to FIG. 7 is only for the two left and right channels by Cch and LFch, and Cch and RFch. Yes.
However, it can be said that the difference in arrival time between channels as described above inevitably occurs when sound is reproduced by actually arranging speakers corresponding to multi-channels in an indoor environment or the like. In view of this, in the headphone device of the present embodiment, if it is possible to set an appropriate arrival time difference as much as possible between as many channels as possible, the headphone device of the present embodiment can reproduce it. The surround sound can be said to be of a high quality with a richer presence.

For this purpose, for example, in a signal system corresponding to an audio drive unit of an appropriate channel, a delay unit for setting an inter-channel arrival time difference is provided. It is conceivable to set a required delay time according to the response.
However, as described above, in consideration of the effects of cost reduction and simplification of the audio signal processing circuit system obtained by omitting the delay device 12, without adding a delay device. It is preferable that the difference in arrival time between channels can be set.
Therefore, in this embodiment, as described below, an inter-channel arrival time difference is set for the headphone device.

FIG. 7A shows the relationship between the listening position (listening position Ltp) and the sound source position of each channel in 5.1ch surround based on the ITU recommendation (ITU-R BS.775-1). . However, the illustration of LFEch is omitted because the sense of localization of the sound is sparse.
Here, the spread angle of each LFch and RFch sound source position with respect to the Cch sound source position (angle formed by a straight line indicating the distance DS-C and each of the straight lines indicating the distance DS-LF and DS-RF) is 30 °. The spread angle of each LSch and RSch sound source position with respect to the Cch sound source position (the angle formed by the straight line indicating the distance DS-C and each of the straight lines indicating the distance DS-LS and DS-RS) is 120 °. It prescribes.

  The distance (sound source distance) between the listener who is normally at the listening position Ltp and the sound source (speaker) of each channel (Cch, LFch, RFch, LSch, RSch) is indicated by a broken line in FIG. , DS-C, DS-LF, DS-RF, DS-LS, and DS-RS. Here, these sound source distances DS-C, DS-LF, DS-RF, DS-LS, and DS-RS can be viewed as distances until the direct sound from each channel reaches the listening position Ltp. it can. Since the distance from the listening position Ltp to the sound source of each channel is equal, the lengths of these sound source distances DS-C, DS-LF, DS-RF, DS-LS, and DS-RS are the same.

  However, since the human ears are on the left and right sides of the head, in reality, the left and right ears of the listener who is at the listening position Lpt are physically located from the center point at which the listening position Ltp is established. Therefore, it is located a certain distance away. This is because when the sound emitted from the sound source of each channel actually reaches the listener's ear at the listening position Ltp, the reaching position is from the listening position Ltp, which is the center point, from the center of the head. It means that it shifts to the left and right by the length to the ear.

  Therefore, in FIG. 7A, the voice arrival point Ap is set in correspondence with the position where the sound emitted from the sound source of each channel arrives corresponding to the right ear. In this case, when the ear hole corresponding to the entrance of the outer ear is regarded as a circular shape, the position near the center is set as the voice arrival point Ap. This is based on the assumption that there is no difference in the path from the ear canal to the eardrum, for example, because the sound from each drive unit passes in common.

Then, the distance (sound source distance) DS-Cr, DS-LFr, DS-RFr, DS-LSr from which the direct sound reaches the sound arrival point Ap from the sound source of each channel (Cch, LFch, RFch, LSch, RSch) DS-RSr do not have the same length, but have different lengths depending on the distance shifted to the right side from the center point serving as the listening position Ltp.
FIG. 7 (b) shows a comparison of the straight lines as the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, and DS-RSr shown in FIG. 7 (a). As can be seen from this figure, the length relationship between the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr is as follows:
DS-RSr <DS-RFr <DS-Cr <DS-LFr <DS-RFr <DS-LSr
It becomes.

In FIG. 7, the distance of the sound source from the listening position Ltp, which is the center point, to each channel is set to 1600 m, and the position 100 mm to the right from the listening position Ltp is set as the voice arrival point Ap. Then, the actual lengths of the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr are
DS-Cr = 1597mm
DS-LFr = 1638mm
DS-RFr = 1554mm
DS-LSr = 1676mm
DS-RSr = 1510mm
It becomes.
In this case, if the shortest sound source distance DS-RSr is the reference (+0 mm), the difference between the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr (between channels) Distance difference) is
DS-Cr = + 87mm
DS-LFr = + 128mm
DS-RFr = + 44mm
DS-LSr = + 166mm
DS-RSr = + 0mmmm
It is expressed as follows.
Further, since it is self-evident, it is not shown in the figure, but the relationship between the position of the voice arrival point corresponding to the left ear and the distance between the voice arrival point corresponding to the left ear and the sound source of each channel is shown in FIG. The sound arrival point Ap corresponding to the right ear shown is symmetrical to the sound source distance.

Here, the difference between the above sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, and DS-RSr (distance between channels) is the difference in arrival time for direct sound from the sound source of each channel, That is, it corresponds to the difference in arrival time between channels.
This means that for each distance from the drive unit corresponding to each channel to the ear in the housing part of the headphone device, for example, the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS shown in FIG. This means that if the above drive units are arranged so as to provide a length difference according to the distance difference between -RSr, as a result, an inter-channel arrival time difference can be set.

Therefore, the inventor of the present application pays attention to this point, and in the configuration of the drive unit mounting of the second example shown in FIG. 3, each distance (from the drive unit to the ear (speech arrival point Ap)) (see FIG. 3) Hereinafter, the unit distance is also set.
In setting the unit distance described below, the listening environment (listening environment) set in FIG. 7 is assumed as the target environment, and the drive unit arrangement is set based on this. For LFEch, as mentioned above, the difference in listening due to differences in the sense of localization and the arrival time with other channels is sparse, so the effectiveness of setting the unit distance for the drive unit of LFEch Is low. For this reason, the following description will refer to unit distances corresponding to channels other than LFEch.

Here, referring to FIG. 3 again, each of the drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, and SPu-f (LS) leads to the right ear voice arrival point Ap. Unit distances Dflf, Dcr, Drf, Drs, and Dfls, which are distances up to, are shown.
Then, depending on the actual mounting of the drive unit in the right acoustic unit 1R shown in FIG. 3, the unit distances Dflf, Dcr, Drf, Drs, Dfls are the same as those shown in FIG. , DS-LSr, DS-RSr, the relationship according to the distance difference is obtained.
For confirmation, the unit distances Dflf, Dcr, Drf, Drs, and Dfls correspond to the sound source distances DS-LFr, DS-Cr, DS-RFr, DS-RSr, and DS-LSr in FIG. .

  It should be noted that “the distance difference between the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr in FIG. 7 with respect to the unit distances Dflf, Dcr, Drf, Drs, Dfls”. `` Relationship in accordance with '' refers to the ratio of lengths between unit distances Dflf, Dcr, Drf, Drs, Dfls, and sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr For example, the relationship between the unit distances Dflf, Dcr, Drf, Drs, and Dfls can be expressed as a sound source distance DS. This includes the same size relationship as -Cr, DS-LFr, DS-RFr, DS-LSr, and DS-RSr.

Furthermore, it is included that the magnitude relationship between two or more predetermined unit distances among the unit distances Dflf, Dcr, Drf, Drs, Dfls is the same as the corresponding magnitude relationship of the sound source distances in FIG. .
The present inventor has the same magnitude relationship among all five unit distances Dflf, Dcr, Drf, Drs, Dfls as the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr. Even if it is not maintained, it has been confirmed that sufficient sound reproduction performance can be obtained practically as long as the size relationship between specific ones among the unit distances Dflf, Dcr, Drf, Drs, Dfls is maintained. .
More specifically, in the case of the right housing portion 1R, drive units SPu-f (LF), SPu- corresponding to channels (LFch, Cch, RFch) in which the sound source is located in front (front) of the listening position Ltp. The unit distances Dflf, Dcr, Drf corresponding to C (R) and SPu-RF are given at least the same magnitude relationship as the corresponding sound source distances DS-Cr, DS-LFr, DS-RFr. To. Then, even if the magnitude relationship including the unit distance Drs and Dfls of the drive unit corresponding to the remaining rear channels (RSch, LSch) is slightly different from that of the sound source distance, it is good enough to withstand viewing It was confirmed that an acoustic feeling can be obtained.

  For example, in reality, if a plurality of drive units are individually attached to each of the multi-channel channels on the housing inner wall 4R having a physically limited space, some restrictions may occur. There is sex. In addition, if the unit distance according to the sound source distance is to be obtained, the restriction becomes more severe. However, as described above, only the unit distance corresponding to a specific drive unit among all the drive units may be set so as to conform to the sound source distance. .

Even in the actual headphone device manufactured as the second example, the mounting positions of the drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, and SPu-f (LS) are determined. By adjusting, unit lengths Dflf, Dcr, Drf, Drs, Dfls can be set to a ratio of the same length as sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr . In addition, make the unit distances Dflf, Dcr, Drf, Drs, Dfls more or less the same as the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr. Can keep. In addition, the unit distances Dflf, Dcr, Drf, Drs, Dfls that correspond to the specific magnitude relationship among the sound source distances DS-Cr, DS-LFr, DS-RFr, DS-LSr, DS-RSr It can also be set in the same way as.
In any case, the right housing part 1R in which the position of the drive units SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, SPu-f (LS) is adjusted in this way, Depending on the headphone device having the left housing part 1L in which the position of the drive unit SPu-f (RF), SPu-C (L), SPu-LF, SPu-LS, SPu-f (RS) corresponding to this is adjusted. Accordingly, the difference in the arrival time of the sound between the channels corresponding to the difference in the reaching distance between the channels set according to FIG. 7 is given. Depending on the headphone device including the housing portion (1R, 1L) configured as described above, for example, the left and right drive units are simply arranged appropriately in the front-rear direction without considering the inter-channel reach distance difference. Compared to the case, it is possible to hear a better surround playback sound.

  When the housing inner wall portion 4R forms a polyhedron as in the second example, it is easy to set the unit distance by setting the orientation of the surface portion to which the drive unit is attached. It becomes possible.

In addition, it has been assumed that the headphone device of the present embodiment has been provided with a plurality of drive units that correspond to multi-channels and that are individually provided according to the number of channels in the left and right housing portions. Explained. However, regarding the configuration in which the sound emitted from the drive unit is diffusely reflected by the housing inner wall portion 4R as the present embodiment, for example, only one drive unit is provided in the left and right housing portions corresponding to the conventional two-channel stereo. The present invention can also be applied to a headphone device having a configuration, and an effect of improving the reproduction sound quality by suppressing unnecessary reverberation can be obtained.
8A and 8B show an example of forming the housing inner wall 4R structure when one drive unit is provided in one housing. In this figure, the same parts as those in FIG.
In this figure, in the housing inner wall 4R of the right acoustic unit 1R, a drive unit SPu-R corresponding to the R channel is attached so that its sound axis is directed toward the voice arrival point Ap as shown in the figure, The housing inner wall 4R has a concave polyhedron structure in accordance with FIG. Of course, also in this case, as shown in FIGS. 4 and 5, a member for irregularly reflecting sound, such as the columnar member assembly member 7 and the fragment member 8, may be further provided.

  In the examples of the drive unit arrangements shown in FIGS. 2 to 5 so far, it is assumed that the model defined as described in FIG. 7 is an ideal listening environment. Can be an ideal listening environment.

Further, the description has been made on the premise that the configuration of the signal system of FIG. 22 is simplified, but conversely, the signal is used for the purpose of reproducing a very faithful sound field. It is not impeded to construct the system.
In this case, for example, the filter 11 and the delay device 12 indicated by broken lines in FIG. 22 are actually provided, and appropriate passband characteristics and delay times are set, and the main audio component and the sub audio component are The signal system is configured such that a strict signal characteristic difference is given, that is, a correspondingly accurate transfer function is convoluted. In this case, for example, if a digital filter is used for the filter 11 as well, the accuracy becomes high.

In addition, regarding the setting of the unit distance in the drive unit mounting example of the second example described with reference to FIGS. 7 and 3, for example, the filter 11 and the delay device 12 indicated by the broken lines in the configuration of the signal system in FIG. 22 are omitted. In addition, although it is a configuration for generating an appropriate inter-channel arrival time difference, it can be used in combination with a configuration in which the filter 11 and the delay device 12 indicated by the broken lines are not omitted as described above.
When the embodiment relating to the drive unit arrangement and the configuration in which the filter 11 and the delay device 12 are not omitted are used in combination, for example, the delay time can be set more precisely by setting a required inter-channel arrival time difference. It is possible to adopt a configuration in which 12 delay times are adjusted.

  In FIG. 22, the signal system of the main audio components of LFch and RFch serving as a reference is not provided with a filter or a delay device. As described above, for LFch and RFch, for example, it is intended to easily obtain the required signal characteristics by utilizing the acoustic characteristics originally assumed by the headphone device (housing). is there. However, strictly speaking, for example, as shown in FIG. 20, there is also a transfer function corresponding to the sound source position for the main audio components of LFch and RFch. The feeling of localization of the sound source becomes better by being folded in. From this, the signal system of the main audio component of LFch and RFch may be provided with a filter (and a delay unit) so that appropriate signal characteristics can be obtained. In this case, the LFch and RFch main sounds that are given through the filter (and delay unit) as described above for sounds corresponding to other output channels other than the main audio components of the LSch and RFch. The signal characteristic difference may be obtained with reference to the signal characteristic of the component.

In addition, the headphone sound reproduction system supported by the present embodiment is compatible with the headphone device according to the present embodiment that is actually worn by the listener on the head and the signal system shown in FIG. 22, for example. And a signal processing circuit unit to be configured. As a combination of the actual configurations of the headphone device and the signal processing circuit unit, for example, one is a system configuration in which the headphone device and the signal processing device unit including the signal processing circuit unit are separated. Can be considered. In this case, transmission of the audio signal from the signal processing unit to the headphone device may be performed, for example, by wire, or may be performed wirelessly by adopting a predetermined wireless transmission / reception method using infrared rays, radio waves, or the like. May be.
As another configuration, a configuration in which a signal processing circuit unit is built in and integrated with a predetermined portion such as a housing unit and a headband unit that constitute the headphone device body of the present embodiment is also conceivable.

Also, as an embodiment, a configuration corresponding to 5.1 channel surround as a multi-channel has been described as an example, but it can also be applied to other channel multi-channel configurations such as 7.1 channel surround. It is said.
In addition, the shape and structure for irregularly reflecting sound on the inner wall portion of the housing can be applied to a headphone device including a plurality of drive units for the housing portion corresponding to one ear for the purpose other than the multi-channel correspondence. Furthermore, the shape and structure for irregularly reflecting sound on the inner wall portion of the housing can be variously considered other than those described with reference to FIGS. For example, it is not impeded that the curved inner housing wall 4R as shown in FIG. 2 is provided with a member for irregularly reflecting sound as shown in FIGS.
Further, for example, the member for irregularly reflecting sound as shown in FIGS. 4 and 5 may be provided so that components as the member are appropriately attached to the surface of the inner wall portion of the housing later. The part corresponding to the member for irregularly reflecting the sound may be integrally formed. Such integral molding can be easily realized, for example, when a resin is used as the material. Then, by forming the housing inner wall portion and the member that irregularly reflects the sound by such integral molding, the manufacturing process can be simplified and the manufacturing cost can be reduced.

It is a perspective view which shows the example of an aspect about the external shape of the headphone apparatus of embodiment. It is a figure which shows the drive unit attachment example (1st example) of embodiment. It is a figure which shows the drive unit attachment example (2nd example) of embodiment. It is a figure which shows the drive unit attachment example (3rd example) of embodiment. It is a figure which shows the drive unit attachment example (4th example) of embodiment. It is a figure which compares and shows the reverberation characteristic of the housing part by the 1st example, 2nd example, and 3rd example of the drive unit attachment example of embodiment. It is the figure which illustrated the model of the listening environment used as a premise in the setting of the drive unit arrangement | positioning in embodiment. It is a figure which shows the example of formation of the housing inner wall part in the headphone apparatus corresponding to 2 channel stereo. It is a figure which shows the example of an acoustic model in the case of listening to one sound source. It is a figure which shows the signal characteristic difference of the main audio | voice component and sub audio | voice component in the acoustic model of FIG. It is a figure which shows the example of an acoustic model in the case of listening to two sound sources. It is a figure which shows the structural example of the audio | voice signal processing system of the headphone acoustic reproduction system corresponding to the acoustic model shown in FIG. It is a figure which shows typically the example of an arrangement | positioning aspect of the drive unit in the headphone apparatus corresponding to FIG. 12 from a plane direction. It is a figure which shows the general acoustic model of 5.1ch surround. It is a figure which shows the structural example of the audio | voice signal processing system of the headphone sound reproduction system corresponding to the acoustic model shown in FIG. It is a figure which shows the basic acoustic model corresponding to the headphone sound reproduction system as embodiment of this invention. It is a figure which shows the example of a setting of the measurement position corresponding to the sound component of each sound source in the acoustic model of FIG. It is a figure which shows the structural example of the audio | voice signal processing system about the headphone sound reproduction | regeneration system corresponding to FIG. It is a figure which shows the example of arrangement | positioning aspect of the drive unit in the headphone apparatus corresponding to the structure of FIG. It is a figure which shows the acoustic model of 5.1ch surround corresponding to the headphone sound reproduction system of embodiment. It is a figure which shows the example of a setting of the measurement position corresponding to the sound component of each sound source in the acoustic model of FIG. It is a figure which shows the structural example of the audio | voice signal processing system of the headphone sound reproduction system of embodiment corresponding to a 5.1ch surround system. It is a figure which shows typically the example of an arrangement | positioning aspect of the drive unit in the headphone apparatus of embodiment corresponding to a 5.1ch surround system from a plane direction. It is a figure which shows typically the example of the arrangement | positioning aspect of the drive unit in the headphone apparatus of embodiment corresponding to a 5.1ch surround system from a side surface direction. It is a figure which shows typically the other example of an arrangement | positioning aspect about the drive unit in the headphone apparatus of embodiment corresponding to a 5.1ch surround system from a side surface direction. It is a circuit diagram which shows the structural example of the filter with which the audio | voice signal processing system of the headphone sound reproduction system of embodiment is equipped. It is a figure which shows the example of a characteristic of the filter shown in FIG.

Explanation of symbols

  1L left housing part, 1R right housing part, 3R ear pad (right housing part side), 4R housing inner wall part (right housing part side), 7 columnar body assembly member, 8 debris member, 11 (11-LS, 11-RS, 11-f (RS), 11-f (LS), 11-C, 11-f (LF), 11-f (RF)) Filter, 12 (12- (RF), 12-f (RS), 12 -(LF), 12-f (LS)) Delay, SPu-f (RF), SPu-C (L), SPu-LF, SPu-LS, SPu-f (RS), SPu-LFE (L) , SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, SPu-f (LS), SPu-LFE (R), SPu-f (RS) LFE (L), SPu- f (LS) LFE (L), SPu-f (RF) C, SPu-f (LF) C drive unit

Claims (5)

In the housing part provided with one or more drive units corresponding to the ears on one side, the housing inner wall part which is the mounting part of the drive unit is formed so that the sound emitted from the drive unit is irregularly reflected.
A headphone device characterized by that. The housing inner wall is formed in a polyhedral shape,
The headphone device according to claim 1. A member for irregularly reflecting sound waves to the inner wall of the housing is disposed;
The headphone device according to claim 2. A member for irregularly reflecting sound waves to the inner wall of the housing is disposed;
The headphone device according to claim 1. In the case where a plurality of drive units are provided in the housing part,
The distance from the sound source position of each channel to the sound arrival point set corresponding to the one ear in the listening environment defined in advance corresponding to the predetermined channel configuration is a sound source distance, and each of the plurality of drive units From the distance to the voice arrival point set corresponding to the above one ear as the unit distance, the length of the unit distance corresponding to each channel is the distance difference according to the sound source distance corresponding to each channel. A plurality of drive units are attached to the inner wall of the housing so as to obtain a relationship.
The headphone device according to claim 1.

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