JPH07203597A - Headphone reproducing device - Google Patents

Abstract

PURPOSE:To fix a sound image in a front part(outside a head) in the same way as that of speaker reproduction at the time of headphone reproduction. CONSTITUTION:A direction detecting circuit 12 detects the direction theta of a viewer 4. A setting circuit 13a reads the inpulse responce of right and left ears for a sound source from a storage circuit 14a and sets it in FIR filters 2c and 2d. The FIR filters 2c and 2d convolutes an acoustic signal from an input terminal 1 by specified inpulse responce and outputs the acoustic signal to the listener 4 with a headphone 3. Thus, the dynamic convolution of inpulse responce can be executed in accordance with the movement of the listener 4 so that the sound image fixing in the front part is realized at the time of headphone 3 reproduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a headphone reproducing apparatus for reproducing realistic sound using headphones in AV (audio / visual) equipment.

[0002]

2. Description of the Related Art In recent years, in the field of audio, portable cassette players that use a headphone reproducing method and players that reproduce optical disks have become widespread. Accordingly, when reproducing headphones, a sound image is forwarded like a speaker reproducing method. It is desired to develop a new headphone playback method such as localization (outside the head).

Here, a conventional headphone reproducing device will be described with reference to the drawings. FIG. 9 is a block diagram showing a configuration of a conventional headphone reproducing apparatus that localizes a sound image in front of a viewer during headphone reproduction. In the figure, first, an acoustic signal is input from the input terminal 1, branched into two, and then input to the FIR filters 2a and 2b. The FIR filters 2a and 2b are digital filters that perform convolution calculation, and the head related transfer functions hL (t) and hR (t) (t represents continuous time, and the input signal is a time function) that localizes the sound image outside the head. It has an impulse response of 1).

In the FIR filters 2a and 2b, the convolution operation of the input signal is performed with a desired tap coefficient so that the sound image is localized in front of the viewer 4 when the signal is reproduced by the headphones 3. The output signals of the FIR filters 2a and 2b are input to the left and right ears of the viewer 4 as acoustic vibrations by the headphones 3. Here, a method for localizing a sound image forward using the FIR filter 2 will be described with reference to FIG.

FIG. 10A shows a state in which the speaker reproduction device 5 converts the acoustic signal S (t) into air vibration and radiates it from the speaker 6 installed in front of the viewer 4. H1 (t) shown in the dotted line shows the impulse response to the speaker 6 and the right ear of the viewer 4, and h2 (t) is the speaker 6
And the impulse response up to the left ear of the viewer 4 is shown.
When the signal S (t) is emitted from the speaker 6, the signal R (t) in the right ear of the viewer 4 is expressed by the equation (1). R (t) = S (t) * h1 (t) ··· (1) Similarly, the signal L (t) in the left ear is expressed by the equation (2) (however, * represents the convolution operation). . L (t) = S (t) * h2 (t) (2) Actually, the impulse response of the speaker 6 itself is convoluted, but it is omitted here. The characteristics of the speaker 6 and the like may be included in h1 (t) and h2 (t).

Next, FIG. 10B shows the structure of a conventional headphone reproducing apparatus for reproducing the signal S (t) by the headphones 3. Similar to FIG. 9, hHR (t) and hHL (t) marked on the left and right ears of the viewer in this figure are impulse responses between the ears of the headphones 3 and the viewer 4. The signal R ′ (t) input to the right ear of the viewer 4 in this case is expressed by the equation (3). R '(t) = S (t) * hR (t) * hHR (t) (3) Similarly, the signal L' (t) input to the left ear of the viewer 4 is
It is expressed by equation (4). L '(t) = S (t) * hL (t) * hHL (t) ... (4)

Here, in the headphone reproducing apparatus, if a signal similar to that of the speaker reproducing apparatus 5 is input to both ears of the viewer 4, the sound image is localized in the front direction. Therefore, hR (t) and hL (t) should be set as follows so that equations (1) and (3) and equations (2) and (4) are equal. h1 (t) = hR (t) * hHR (t) .. (6) h2 (t) = hL (t) * hHL (t) .. (7) At this time, the sound image is localized in front of the headphones during playback. It will be. In equations (6) and (7), h1 (t), h2
Since (t), hHR (t), and hHL (t) are obtained by actual measurement, hR (t) and hL (t) can be calculated. Although there are several methods for obtaining the values of these equations, a method for obtaining the values by converting them into the frequency domain will be described below.

First, Fourier transforms of the impulse responses of the FIR filters are given in (8) to (1) below.
When expressed as the equation (3), the equations (6) and (7) described above become the equations (14) and (15). Here, FFT (x) represents a function for Fourier transforming x, and ω represents an angular frequency. H1 (ω) = FFT (h1 (t)) ・ ・ (8) H2 (ω) ＝ FFT (h2 (t)) ・ ・ (9) HR (ω) ＝ FFT (hR (t)) ・ ・ (10 ) HL (ω) = FFT (hL (t)) ・ ・ (11) HHR (ω) ＝ FFT (hHR (t)) ・ ・ (12) HHL (ω) ＝ FFT (hHL (t)) ・ ・(13) H1 (ω) = HR (ω) ・ HHR (ω) ・ ・ (14) H2 (ω) = HL (ω) ・ HHL (ω) ・ ・ (15)

Therefore, the following equations (16) and (17) are calculated from the obtained equations (14) and (15). HR (ω) = H1 (ω) / HHR (ω) ··· (16) HL (ω) = H2 (ω) / HHL (ω) ··· (17) And the HR (of (16) and (17) ( Inverse Fourier transform of ω), HL (ω) (represented by IFFT (X)) gives the following (18),
Equation (19) is calculated. hR (t) = IFFT (HR (ω)) ··· (18) hL (t) = IFFT (HL (ω)) · · (19) In this way, the impulse response hR (t), hL (t) can be obtained. it can.

The impulse response obtained as described above is set as the tap coefficient of the FIR filters 2a and 2b,
The sound image can be localized in the front by performing the convolution operation with the input signal.

FIR filter 2 for performing a convolution operation here
The basic configuration of a and 2b is shown in FIG. In this figure, the FIR filter 2 has a signal input terminal 7 and a signal τ1.
A plurality of delay elements 8 for delaying by time, tap coefficient (h
(n)) and a plurality of multipliers 9 for multiplying the input signal and the delay signal of each delay circuit, an adder 10 for adding the outputs of the multipliers 9, and a conversion signal output terminal 11. Usually, for such an FIR filter, a DSP (Digital Signal Processor) for performing multiplication and addition at high speed or a dedicated LSI is used. The impulse response h (n) (n: 0 to N-1, where N is the length of the required impulse response) is set as a tap coefficient in each multiplier 9 as shown in FIG. A delay time τ ₁ corresponding to the sampling frequency when converting an analog signal into a digital signal is set. Then, the convolution operation is executed by repeating multiplication and addition and delay for the input signal. Since this signal processing is performed on the digital signal, the A / D converter for converting the analog signal into the digital signal and the D / A converter for converting the digital signal into the analog signal are actually FIR before the FIR filter 2.
Required after filter 2. It is omitted in this figure (same below).

[0012]

However, in such a configuration, when the impulse response of each viewer is set in the FIR filter, the sound image is localized forward, but the impulse response set for other viewers is set. In the case of using the headphone reproducing apparatus having the above, there is a drawback that it is difficult to localize the sound image in the front because there is an individual difference in the hearing characteristics. Further, in the conventional headphone reproducing device, there is a problem that the sound image position does not change according to the change of the head direction of the viewer.

The present invention has been made in view of the above-mentioned problems of the prior art. Even when a standard impulse response is used, the sound image is localized in front of a large number of viewers. The present invention aims to realize a headphone reproducing device in which the position of the sound image is automatically changed according to the change of the direction of the head by the viewer.

[0014]

The invention according to claim 1 of the present application comprises headphones for outputting sound to the left and right ears of a viewer,
Headphones or direction detection means attached to the head of a viewer wearing headphones and detecting the orientation of the viewer's head and acoustic signals are input, and convolution calculation is performed to localize the sound image in any direction. A plurality of calculation means for outputting the converted acoustic signal to the headphones, and a storage means for storing the convolution coefficient of each calculation means corresponding to each direction of the viewer's head detected by the direction detection means, Setting means for reading the coefficient of convolution in the computing means from the storage means and setting the coefficient in the computing means in correspondence with the direction detected by the direction detecting means.

According to a second aspect of the present invention, the headphones for outputting sound to the left and right ears of the viewer and the headphones or the head of the viewer wearing the headphones are attached to detect the orientation of the viewer's head. Direction detection means, a sound signal is input, reflected sound addition means for outputting a sound signal obtained by adding a reflected sound to the direct sound to the headphones, and each direction of the viewer's head detected by the direction detection means. Correspondingly, storage means for storing each creation data of the reflected sound of the reflected sound adding means, and setting means for reading the created data corresponding to the direction detected by the direction detecting means from the storage means and setting it in the reflected sound adding means. And are provided.

According to the invention of claim 3 of the present application, the headphones for outputting sound to the left and right ears of the viewer and the headphones or the head of the viewer wearing the headphones are attached to detect the orientation of the viewer's head. Direction detecting means, a plurality of calculating means for inputting an acoustic signal, performing a convolution calculation for localizing a sound image in a specific direction, and a plurality of delaying means for delaying an output signal of the calculating means by an arbitrary time, The output signal of the delay means is divided into a plurality of frequency bands, and a plurality of sets of dividing means for controlling the output level of the divided signals and the signals divided into the respective frequency bands of the dividing means are added and output to the headphones. And a control unit for controlling the delay time of the delay unit and the output level value of the dividing unit, which correspond to each direction of the viewer's head detected by the direction detecting unit. It is an.

According to the invention of claim 4 of the present application, the headphone for outputting sound to the left and right ears of the viewer and the headphone or the head of the viewer wearing the headphone are attached to detect the orientation of the head of the viewer. Direction detecting means, an acoustic signal is inputted, reflected sound adding means for generating an acoustic signal by adding a reflected sound to a direct sound, and a plurality of delays for delaying an output signal of the reflected sound adding means by an arbitrary time. Means and a plurality of sets of dividing means for dividing the output signal of the delay means into a plurality of frequency bands and controlling the output level of the divided signals,
The adding means for adding the signals divided into each frequency band of the dividing means and outputting to the headphones, and the delay time of the delay means and the delay time of the dividing means corresponding to each direction of the viewer's head detected by the direction detecting means Control means for controlling the output level values respectively,
It is characterized by including.

According to the invention of claim 5 of the present application, the headphone for outputting sound to the left and right ears of the viewer and the headphone or the head of the viewer wearing the headphone are attached to detect the orientation of the head of the viewer. Direction detection means, a plurality of calculation means for inputting an acoustic signal, performing a convolution calculation for localizing a sound image in an arbitrary direction, and generating a converted acoustic signal, and a viewer detected by the direction detection means First storage means for storing each convolution coefficient of the calculation means corresponding to each direction of the head and a signal of the calculation means are input, and an acoustic signal in which a reflected sound is added to a direct sound is generated. Detected by the reflected sound adding means, a second storage means corresponding to each direction of the viewer's head detected by the direction detecting means and storing each creation data of the reflected sound of the reflected sound adding means, and detected by the direction detecting means. Depending on the direction Setting means for reading the convolution coefficient in 1) from the first storage means and setting it in the computing means, and reading the created data in the reflected sound addition means from the second storage means and setting it in the reflected sound addition means. It is characterized by doing.

According to the invention of claim 6 of the present application, the headphones for outputting sound to the left and right ears of the viewer and the headphone or the head of the viewer wearing the headphones are attached to detect the orientation of the viewer's head. Direction detection means, a plurality of calculation means for inputting an acoustic signal and performing a convolution calculation for localizing a sound image in a specific direction, and a signal of the calculation means are input, and a reflected sound is added to a direct sound. Reflected sound addition means for generating an acoustic signal, a plurality of delay means for delaying the output signal of the reflected sound addition means by an arbitrary time, and the output signal of the delay means is divided into a plurality of frequency bands, and the divided signals A plurality of sets of dividing means for controlling the output level of the above, an adding means for adding the signals divided into each frequency band of the dividing means and outputting to the headphones, and a head for each direction of the viewer's head detected by the direction detecting means. Corresponds to and is characterized by comprising a control means for respectively controlling the output level value of the delay time and dividing means of the delay means.

[0020]

According to the invention of claim 1 of the present application having such a feature, the direction detecting means is attached to the head of the viewer wearing the headphones or the headphone, and detects the orientation of the head of the viewer. The storage means stores the coefficient of each convolution of the calculation means corresponding to each direction of the viewer's head detected by the direction detection means. Next, the setting means reads out a desired convolution coefficient from the storage means corresponding to the direction detected by the direction detection means and sets it in the calculation means. Then, when the acoustic signal is input, the calculation means performs a convolution calculation for localizing the sound image in an arbitrary direction, and outputs the converted acoustic signal to the headphones. By doing so, the position of the sound image heard from the headphones automatically changes in response to the movement of the viewer.

According to the invention of claim 2 of the present application, the direction detecting means is attached to the head of the viewer wearing the headphones or the headphone and detects the orientation of the head of the viewer. The storage means stores each creation data of the reflected sound and the reverberant sound of the reflected sound adding means corresponding to each direction of the viewer's head detected by the direction detecting means. Next, the setting means reads out the created data corresponding to the direction detected by the direction detecting means from the storage means and sets it in the reflected sound adding means. Then, when the acoustic signal is input, the reflected sound adding unit outputs to the headphones an acoustic signal obtained by adding a reflected sound and a reverberant sound to the direct sound. In this way, the reflected sound and reverberant sound of the sound source heard from the headphones change according to the movement of the viewer.

According to the third aspect of the present invention, the direction detecting means is attached to the headphone or the head of the viewer wearing the headphone and detects the orientation of the head of the viewer. When the acoustic signal is input, the calculation means performs a convolution calculation for localizing the sound image in a specific direction. Then, the delay means delays the output signal of the arithmetic means by an arbitrary time. Further, the dividing means divides the output signal of the delay means into a plurality of frequency bands and controls the output level of the divided signal. The control means controls the delay time of the delay means and the output level value of the dividing means corresponding to each direction of the viewer's head detected by the direction detecting means. The adding means adds the signals divided into the respective frequency bands of the dividing means and outputs to the headphones. By doing so, the position of the sound image heard from the headphones automatically changes in response to the movement of the viewer without providing the reflection sound adding means and the storage means.

According to the invention of claim 4 of the present application, the direction detecting means is attached to the head of the viewer wearing the headphones or the headphone, and detects the orientation of the head of the viewer. When the acoustic signal is input, the reflected sound adding means outputs an acoustic signal in which a reflected sound or a reverberant sound is added to the direct sound. The delay means delays the output signal of the reflected sound adding means by an arbitrary time. Further, the dividing means divides the output signal of the delay means into a plurality of frequency bands and controls the output level of the divided signal. The control means controls the delay time of the delay means and the output level value of the dividing means corresponding to each direction of the viewer's head detected by the direction detecting means. The adding means adds the signals divided into the respective frequency bands of the dividing means and outputs to the headphones. By doing so, the position of the sound image heard from the headphones automatically changes in response to the movement of the viewer without providing a calculation unit or a storage unit.

According to the fifth aspect of the present invention, the direction detecting means is attached to the headphone or the head of the viewer wearing the headphone, and detects the orientation of the head of the viewer. The first storage means stores the coefficient of each convolution of the calculation means corresponding to each direction of the viewer's head detected by the direction detection means. The second storage means stores the respective created data of the reflected sound and the reverberant sound of the reflected sound adding means corresponding to each direction of the viewer's head detected by the direction detecting means. Next, the setting means reads out the created data corresponding to the direction detected by the direction detecting means from the storage means and sets it in the reflected sound adding means. When the reflected sound adding means receives the signal from the calculating means, the reflected sound adding means outputs to the headphones an acoustic signal obtained by adding reflected sound or reverberant sound to the direct sound. This automatically changes the position of the sound image of the sound source heard from the headphones in response to the viewer's movement, and changes the reflected sound and reverberant sound of the sound source.

According to the invention of claim 6 of the present application, the direction detection means is attached to the headphone or the head of the viewer wearing the headphone and detects the orientation of the head of the viewer. When the acoustic signal is input, the calculation means performs a convolution calculation for localizing the sound image in a specific direction. When the signal is input from the calculating means, the reflected sound adding means outputs an acoustic signal in which reflected sound or reverberant sound is added to the direct sound. The delay means delays the output signal of the reflected sound adding means by an arbitrary time. Further, the dividing means divides the output signal of the delay means into a plurality of frequency bands and controls the output level of the divided signal. The control means controls the delay time of the delay means and the output level value of the dividing means corresponding to each direction of the viewer's head detected by the direction detecting means. The adding means adds the signals divided into the respective frequency bands of the dividing means and outputs to the headphones. By doing so, the position of the sound image of the sound source heard from the headphones is automatically changed in response to the movement of the viewer, and the reflected sound or reverberant sound of the sound source is generated without providing a storage unit for the calculation unit and the reflected sound adding unit. Change.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A headphone reproducing device according to a first embodiment of the present invention will be described with reference to the drawings. Figure 1 is the first
It is a block diagram showing the composition of the headphone reproducing device in an example. The parts having the same functions as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted. In FIG.
The acoustic signal input to the input terminal 1 is the FIR filter 2
c, 2d. The FIR filter 2c is a calculation means for generating a signal corresponding to the sound output from the speaker of the speaker reproducing device to the left ear of the viewer 4, and is composed of a digital filter for performing convolution calculation on the input signal with a predetermined impulse response. . The FIR filter 2d is also a calculation means for generating a signal corresponding to the sound output from the speaker of the speaker reproducing device to the right ear of the viewer 4 and is composed of a digital filter.

The direction detector 12 is attached to the headphone 3 of the viewer 4 or the head of the viewer. Direction detector 12
Is a direction detecting means for detecting the direction in which the head of the viewer 4 is facing, and is composed of, for example, a geomagnetic sensor or an acceleration sensor using geomagnetism. In the case of a geomagnetic sensor, the displacement angle with respect to the meridian is detected, and in the case of an acceleration sensor,
The movement of the head in the horizontal plane is detected as acceleration. The setting circuit 13a controls the direction θ of the viewer 4 from the direction detection circuit 12.
Is a setting means for setting predetermined impulse response data based on the above, and outputting the value from the memory circuit 14a. The memory circuit 14a includes a speaker (not shown) placed in front of the viewer 4 when the typical viewer 4 faces several kinds of directions.
The storage means stores the impulse response data between the two ears as set data for each direction.

The operation of the headphone reproducing apparatus according to the first embodiment having the above configuration will be described. First, an acoustic signal such as music is input from the input terminal 1 and input to the FIR filters 2c and 2d. FIR filters 2c, 2
At d, the desired impulse response coefficient set by the setting circuit 13a is read from the storage circuit 14a,
It is given as a tap coefficient of each multiplier in the FIR filter 2. In this memory circuit 14a, a plurality of impulse responses between a representative viewer and both ears of a doll called a dummy head and a speaker placed in front are stored (in a pair for left and right). There is.

FIG. 2 is an explanatory diagram showing the types of impulse responses with respect to the direction θ of the viewer 4. FIG. 2A shows a state in which a typical viewer 4 faces the front front with respect to the speaker 6 connected to the speaker reproducing device 5. Impulse responses between the left and right ears of the viewer 4 and the speaker 6 at this time are hL0 (t) and hR0 (t), respectively. FIG. 2B shows a state in which the viewer 4 faces leftward by θ 1 with respect to the front speaker, and in this case, the left and right ears of the viewer 4 and the speaker 6 are shown.
The impulse responses between them are hLL1 (t) and hLR1 (t), respectively.
Similarly, Fig. 2 (c) shows the case of moving to the left by θ2, and the impulse responses at this time are hLL2 (t) and hLR2 (t), respectively. When facing, the impulse responses at this time are hRL1 (t) and hRR1 (t), respectively. In Fig. 2 (e), when facing right by θ4, the impulse responses at this time are hRL2 (t) and hRL2 (t), respectively. hRR2 (t).

As shown in FIG. 2, the impulse responses corresponding to the directions of the respective viewers are stored in the storage circuit 14a in pairs for left and right. However, the direction resolution is set according to the scale of the storage circuit 14a, but if 360 ° is set at intervals of 1 °, for example, it is necessary to store 720 impulse response data. It should be noted that considering that the left and right impulse responses are opposite when the viewer 4 faces left and at the same angle right, it is possible to reduce the amount of data in the memory circuit 14a by half. is there. Further, the data amount of the orientation θ of 5 ° can be reduced by a method of interpolating the data when the orientations are 0 ° and 10 °.

Now, the direction θ of the viewer 4 is the direction detection circuit 1
2 and the signal is given to the setting circuit 13a. Next, the setting circuit 13a selects, from the storage circuit 14a, the data of the impulse response set corresponding to the direction θ of the viewer 4 output from the direction detection circuit 12, and sets the data in the FIR filters 2c and 2d. For example, in FIG.
As shown in (b), when the viewer 4 moves to the left by θ1, hLR1 (t) and hLL1 (t) are read from the memory circuit 14a and set in the multipliers of the FIR filters 2c and 2d.

As described above, the viewer 4 can hear the signal convoluted with the impulse response when the speaker is placed in the front even from the headphones 3 even when facing the left and right sides,
The sound image is always felt in the front direction of the speaker. Humans usually move their heads to find the direction of the sound source. First
The headphone reproducing apparatus according to the embodiment captures the movement of the viewer 4 as a change in the direction θ, thereby absorbing individual differences in the sound image, and dynamic front localization of the sound that could not be realized by only the static impulse response. Can be realized. For example, when the viewer 4 wears headphones and moves in the room, the sound pressure of the left and right ears changes according to the movement, and the change in sound due to the movement can be naturally felt.

Next, a headphone reproducing apparatus according to the second embodiment of the present invention will be described with reference to FIG. Figure 3
FIG. 7 is a block diagram showing a configuration of a headphone reproducing device according to a second embodiment. In this figure, the direction detection circuit 12 is attached to the headphones 3 of the viewer 4 and an acoustic signal is input from the input terminal 1 as in the first embodiment. The acoustic signal from the input terminal 1 is given to the reflected sound adding circuit 15a. The reflected sound adding circuit 15a is a reflected sound adding unit that adds a reflected sound or a reverberant sound equivalent to the acoustic space in which the viewer 4 is present to the direct sound.

FIG. 4A is a plan view showing the propagation paths of the direct sound and the reflected or reverberant sound of the sound emitted from the speaker 6 in the acoustic space in which the viewer 4 is present. FIG. 3B is a block diagram showing a configuration example of the reflected sound adding circuit 15. In FIG. 4A, direct sounds to the left and right ears of the viewer 4 are DL and DR, respectively. Further, the sound A incident on the left wall 16L is reflected, and the reflected sound or reverberant sound to the left and right ears of the viewer 4 is AL and AR, respectively. Similarly, the sound B incident on the right wall 16R is reflected, and the reflected sound and the reverberant sound to the left and right ears of the viewer 4 are BL and BR, respectively.

In FIG. 4B, the signal at the input terminal 1 of FIG. 1 is given to the delay devices 17a, 17b, 18a and 18b. The delay devices 17a and 17b are circuits that delay the signal by a time corresponding to the propagation time of the reflected sounds AL and AR from the sound source (speaker 6) to the viewer 4, and the delay devices 18a and 1b
Reference numeral 8b is a circuit that delays the signal by a time corresponding to the propagation time of the reflected sounds BL and BR from the sound source to the viewer 4. The multipliers 19a and 19b are circuits for attenuating or amplifying the outputs of the delay devices 17a and 17b, and the output level thereof is set so as to correspond to the sound pressure of each reflected sound. Similarly, the multipliers 20a, 2
Reference numeral 0b is a circuit for attenuating or amplifying the outputs of the delay devices 18a and 18b. The adder 21a is a circuit that adds the respective outputs of the multipliers 19a and 20a and the signal of the input terminal 1. Similarly, the adder 21b is a circuit that adds the respective outputs of the multipliers 19b and 20b and the signal of the input terminal 1.

In FIG. 3, the storage circuit 14b is a storage means for storing the reflected sound creation data corresponding to the direction θ of the viewer 4, and the delay time of the delay devices 17 and 18, and the multiplier 1
The gains of 9 and 20 are stored for each direction θ of the viewer 4. Further, the setting circuit 13b is a setting means for giving the reflected sound creation data stored in the storage circuit 14b to the reflected sound adding circuit 15a in accordance with the orientation θ of the viewer 4 detected by the direction detecting circuit 12.

The operation of the headphone reproducing apparatus according to the second embodiment having the above structure will be described. In FIG. 3, a signal such as music input to the input terminal 1 is reflected sound adding circuit 1
5a is input. The reflected sound adding circuit 15a adds a reflected sound and a reverberant sound to the input signal. It is assumed that the viewer 4 is listening to the sound emitted from the speaker 6 in the room surrounded by the wall 16 as shown in FIG. At this time, various reflected sounds from the wall 16 are incident on the viewer 4, and sounds of typical propagation paths are A and B. At the same time as listening to the direct sounds DL and DR, the viewer 4 hears the reflected sounds (reverberation sounds) AL and BL with the left ear and the reflected sounds (reverberation sounds) BR and AR with the right ear.

It is considered that the reflected sounds AL and AR directed to the viewer 4 have different arrival times to both ears and have different amplitude levels. The same applies to the reflected sounds BL and BR. Direct sound D is applied to the delay units 17a and 17b of FIG.
The time difference between the reflected sounds AL and AR with respect to L and DR is set. In addition, direct sounds DL and D are applied to the delay devices 18a and 18b.
The time difference between the reflected sounds BL and BR with respect to R is set. Next, the amplitude levels of the reflected sounds AL and AR are set in the multipliers 19a and 19b, and the amplitude levels of the reflected sounds BL and BR are set in the multipliers 20a and 20b. Then, the outputs of the multipliers 19a and 20a and the signal of the input terminal 1 as the direct sound DL are respectively added by the adder 21a, and the signals are output to the headphones 3 on the left side of FIG. Similarly, the multiplier 19b,
The respective outputs of 20b and the signal of the input terminal 1 as the direct sound DR are respectively added by the adder 21b, and the signal is output to the headphones 3 on the right side of FIG.

By doing so, it is possible to simply realize the headphone reproduction in the same state as the speaker reproduction. For example, when the viewer 4 moves around the room while carrying the headphone reproducing device, it is possible to naturally feel the change in the reflected sound to the viewer. In reality, there are many reflected sounds in the room, but the configuration of the reflected sound adding circuit 15a may be determined so that only the main reflected sounds (for example, four paths) are realized.

Next, a headphone reproducing apparatus according to the third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the headphone reproducing apparatus in the third embodiment. The same parts as those in the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted. In this figure, the acoustic signal at the input terminal 1 is the FIR filter 2a,
Given to 2b. The FIR filters 2a and 2b have the same circuit as the conventional FIR filter shown in FIG. 9, and the impulse response hL when the sound source is located in front of the center of the viewer 4
It is a digital filter having only (t) and hR (t). The outputs of the FIR filters 2a and 2b are the delay devices 22 respectively.
a, 22b.

The delay devices 22a and 22b are delay means for delaying the input signal by the delay time of the sound due to the sound propagation path, and the delay time is controlled by the control circuit 25 described later. The output of the delay circuit 22a is given to the division circuits 23a and 23b, and the output of the delay circuit 22b is divided circuits 23c and 23b.
given to d. The dividing circuits 23a and 23b are dividing means for the left ear which divides the input signal into a high tone and a low tone and controls the level thereof. For example, the division circuit 23a includes a high-pass filter (HPF), and when the value of the direction θ output from the direction detection circuit 12 by filtering a high tone increases, the output signal of the sound is attenuated by the control signal of the control circuit 25. The dividing circuit 23b includes a low-pass filter (LPF), and when the low tone is filtered to increase the value of the direction θ, the control signal of the control circuit 25 attenuates the output level of the tone more gently than in the case of the high tone.

The dividing circuits 23c and 23d are right ear dividing means for dividing the input signal into a high tone and a low tone and controlling the level thereof. The division circuit 23c filters high-pitched sound, and when the value of the direction θ output from the direction detection circuit 12 increases, the output signal of the sound is attenuated or amplified by the control signal of the control circuit 25. Similarly, the dividing circuit 23d filters low-pitched sound and outputs the direction θ.
When the value of is increased, the control signal of the control circuit 25 attenuates or amplifies the output level of the sound.

The outputs of the dividing circuits 23a and 23b are the adder 2
4a, and the outputs of the dividing circuits 23c and 23d are given to the adder 24b. The adder 24a is an addition means for adding the high-pitched sound signal and the low-pitched sound signal of the left ear, and the adder 24b is an addition means for adding the high-pitched sound signal and the low-pitched sound signal of the right ear. Is output. The control circuit 25 is a control unit that controls the delay time of the delay device 22 and the output level of the division circuit 23 in accordance with the direction θ of the viewer 4 detected by the direction detection circuit 12.

The operation of the thus constructed headphone reproducing apparatus of the third embodiment will be described. The signal such as music input to the input terminal 1 is given to the FIR filters 2a and 2b. The FIR filters 2a and 2b are set with an impulse response of front localization (on the front of the speaker) for a typical viewer. When the viewer 4 turns his / her head forward and the direction θ is 0 °, the delay times of the delay devices 22a and 22b are both set to the same minimum value, and the signal is output to the division circuit 23. . Dividing circuits 23a, 23 in this case
The output level of b is also the same, and the output levels of the dividing circuits 23c and 23d are also controlled to be the same. Therefore, the sound of the left-right phase or the like is output from the headphones 3 to both ears as if output from the front speaker.

Next, the viewer 4 turns his head to the left, for example, θ.
I'm just going to In this case, due to the analysis of the ear and the resonance, the amount of high-tone sound is attenuated and the amount of high-tone sound incident to the right ear is increased as compared with low-pitched sound, for example. At this time, the control circuit 25 causes the delay device 22 to
The delay time of a is increased and the delay time of the delay device 22b is decreased. Further, the control circuit 25 lowers the output level of the division circuit 23a and raises the output level of the division circuit 23c. When controlled in this manner, a sound is output from the headphones 3 as if the sound source moved to the right with respect to the head of the viewer 4.

The control circuit 25 controls the delay time of the delay device 22 and the passage gain of the division circuit 23 in accordance with the left and right movements of the viewer detected by the direction detection circuit 12.
This assumes that there is little change in the impulse response between the speaker placed in front and the viewer's both ears with respect to the left and right movements of the viewer 4. However, the difference is based on the idea that it is the difference between the time of a signal that reaches the left and right and the amplitude of a predetermined band.

By such an operation, it is possible to simply radiate sound with front localization by reproducing the headphones without having all impulse responses according to the movement of the viewer 4 as in the first embodiment. Therefore, the memory circuit is not required unlike the first and second embodiments. Although the division circuit is composed of the LPF and the HPF here, the division circuit may be combined with a BPF (bandpass filter) and divided into a plurality of frequencies for control.

Next, a headphone reproducing apparatus according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing the configuration of the headphone reproducing device in the fourth embodiment. In the figure, the same parts as those in the first to third embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.
The acoustic signal from the input terminal 1 is given to the reflected sound adding circuit 15b. The reflected sound adding circuit 15b has the same function as the reflected sound adding circuit 15a of the second embodiment, and is a reflected sound adding means for adding reflected sound or reverberant sound to the input signal. or,
Similar to the third embodiment, the delay devices 22a and 22b, the dividing circuits 23a to 23d, the adders 24a and 24b, and the control circuit 25 are provided.

The operation of the headphone reproducing apparatus according to the fourth embodiment having the above structure will be briefly described. The signal input to the input terminal 1 is input to the reflected sound adding circuit 15b. The basic function of the reflected sound adding circuit 15b is the same as that of the reflected sound adding circuit 15a, but the set reflected sound creating data is used when the viewer 4 is facing the front of the speaker (θ = 0. (°) data is only set. The output signal of the reflected sound adding circuit 15b is the delay device 2
2a, 22b, but the operation of the circuit thereafter is the third
It is similar to the embodiment.

As described above, the reflected sound adding circuit 15b having a single function is used to easily realize the reproduction of the speaker and the equal sound image. That is, by controlling the propagation time and the level of each frequency of the sound output to the left and right ears without having the reflected sound creation data for each direction θ, the reproduction according to the movement of the viewer 4 can be simply performed. And realizes front localization by playing headphones.

Next, a headphone reproducing apparatus according to the fifth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing the configuration of the headphone reproducing apparatus according to the fifth embodiment. The same parts as those in the first to fourth embodiments are designated by the same reference numerals, and the description thereof will be omitted. The acoustic signal input to the input terminal 1 is given to the same FIR filters 2c and 2d as in FIG. The FIR filters 2c and 2d are calculation means for generating a signal corresponding to the sound output from the speaker of the speaker reproducing device, and the output thereof is given to the reflected sound adding circuit 15a.

A first storage circuit 14b is connected to the FIR filters 2c and 2d, and a second storage circuit 14b is connected to a reflected sound addition circuit 15a as reflected sound addition means. The storage circuit 14b is a circuit that stores the impulse response between the speaker placed in front and both ears when the viewer 4 is facing in a certain direction. The storage circuit 14c is a circuit for storing the reflected sound creation data corresponding to the direction of the viewer 4. The read control signal of the storage circuits 14b and 14c is output by the setting circuit 13c. The setting circuit 13c detects the left / right direction θ of the viewer 4 detected by the direction detection circuit 12.
Corresponding to, the data stored in the memory circuit 14b and the memory circuit 14c is selected, and the FIR filters 2c, 2d,
And a setting means for outputting the data to the reflected sound adding circuit 15a.

The operation of the headphone reproducing apparatus according to the fifth embodiment thus constructed is realized by combining the operations of the headphone reproducing apparatus according to the first and second embodiments. That is, the convolution of the impulse response by the front speaker and the simple addition of reflected sound can further improve the front localization.

Next, a headphone reproducing apparatus according to the sixth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a block diagram showing the structure of the headphone reproducing apparatus of the sixth embodiment. The same parts as those in the first to fifth embodiments are designated by the same reference numerals, and the structure will be briefly described. The acoustic signal from the input terminal 1 is given to the same FIR filters 2a and 2b as in FIG. The signal converted into the fixed impulse response here is input to the reflected sound adding circuit 15b, and the acoustic signal added with the reflected sound is given to the delay units 22a and 22b. Delay device 2
2a and 22b delay the acoustic signal by the delay time set by the control circuit 25, and divide the signal into the dividing circuits 23a to 23d.
Output to. The adders 23a and 23b synthesize the signals input to the left and right ears and give the synthesized signals to the headphones 3.

The operation of the headphone reproducing apparatus according to the sixth embodiment thus constructed is the same as the combination of the operations of the third and fourth embodiments. In this embodiment, the forward localization of the sound image can be further improved by convoluting the impulse response by the FIR filters 2a and 2b and simply adding the reflected sound by the reflected sound adding circuit 15b.

In each of the above embodiments, the direction detection is considered only in the left and right directions of the viewer, but the accuracy of the front localization can be further improved by taking into consideration the movement in the vertical direction. Further, although the input signal is intended for a one-channel acoustic signal as monaural, basically, when processing a stereo acoustic signal, the operation of the object of the present invention is realized simply by adding a circuit of the same type. be able to. Further, the FIR filter 2 is composed of the delay device, the multiplier and the adder as shown in FIG. 11, but an IC for signal operation such as DSP may be used to perform a considerable operation.

[0057]

As described above, according to the present invention, the direction in which the viewer is facing is detected by the direction detecting means, and the signal processing corresponding to the motion of the viewer is added to the input acoustic signal, whereby the static sound is obtained. It is possible to realize forward localization of the sound image by reproducing the headphones by performing convolution of the dynamic impulse response instead of convolution of the normal impulse response. Therefore, even if the viewer carries the headphone reproduction device and moves in the acoustic space or changes the direction of the head, the viewer can hear the sound signal of the sound source as if it were emitted from the spice reproduction device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a headphone reproducing device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an impulse response example stored in a storage circuit in the headphone reproducing device according to the first embodiment.

FIG. 3 is a block diagram showing a configuration of a headphone reproducing device according to a second embodiment of the present invention.

FIG. 4A is an explanatory diagram showing propagation paths of a direct sound and a reflected sound emitted from a speaker, and FIG. 4B shows a configuration example of a reflected sound addition circuit included in the headphone reproducing apparatus according to the second embodiment. It is a block.

FIG. 5 is a block diagram showing a configuration of a headphone reproducing device according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a headphone reproducing device according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a headphone reproducing device according to a fifth embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a headphone reproducing device according to a sixth embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration example of a conventional headphone reproducing device.

FIG. 10A is an explanatory diagram showing an impulse response between a speaker reproducing device and a viewer, and FIG. 10B is an explanatory diagram of forward localization using headphones of the headphone reproducing device.

FIG. 11 is a block diagram showing a general configuration of an FIR filter.

[Explanation of symbols]

1 Input Terminals 2a, 2b, 2c, 2d FIR Filter 3 Headphones 4 Viewer 5 Speaker Playback Device 6 Speaker 8 Delay Element 9, 19a, 19b, 20a, 20b Multiplier 10, 20a, 20b, 24a, 24b Adder 12 Direction Detection circuit 13a, 13b, 13c Setting circuit 14a, 14b, 14c Storage circuit 15a, 15b Reflected sound addition circuit 16, 16L, 16R Wall 17a, 17b, 18a, 18b, 22a, 22b Delay device 23a, 23b, 23c, 23d Split Circuit 25 Control circuit

Claims (7)

[Claims] 1. Headphones that output sound to the left and right ears of a viewer, and direction detection means that is attached to the headphone or the head of the viewer wearing the headphones and that detects the orientation of the head of the viewer. An acoustic signal is input, a convolution operation for localizing a sound image in an arbitrary direction is performed, and a plurality of calculating means for outputting the converted acoustic signal to the headphones, and the viewer's head detected by the direction detecting means Storage means for storing each convolution coefficient of the calculation means corresponding to each direction of the section; and the convolution coefficient in the calculation means corresponding to the orientation detected by the direction detection means from the storage means. A headphone reproducing apparatus, comprising: a setting unit that reads out and sets the calculation unit. 2. Headphones that output sound to the left and right ears of the viewer, and direction detection means that is attached to the headphone or the head of the viewer wearing the headphones and that detects the orientation of the head of the viewer. An acoustic signal is input, reflected sound adding means for outputting to the headphones an acoustic signal obtained by adding reflected sound to direct sound, and corresponding to each direction of the viewer's head detected by the direction detecting means, Storage means for storing each created data of the reflected sound of the reflected sound adding means, and setting for reading the created data from the storage means in correspondence with the direction detected by the direction detecting means and setting it in the reflected sound adding means A headphone reproducing device comprising: 3. Headphones that output sound to the left and right ears of the viewer, and direction detection means that is attached to the headphone or the head of the viewer wearing the headphones and that detects the orientation of the head of the viewer. A plurality of calculation means for inputting an acoustic signal and performing a convolution calculation for localizing a sound image in a specific direction, a plurality of delay means for delaying an output signal of the calculation means by an arbitrary time, and an output of the delay means A plurality of sets of dividing means for dividing the signal into a plurality of frequency bands and controlling the output level of the divided signals, and an addition for adding the signals divided into the respective frequency bands of the dividing means and outputting to the headphones Means and control means for controlling the delay time of the delay means and the output level value of the dividing means, which correspond to each direction of the viewer's head detected by the direction detecting means. A headphone reproducing device characterized by: 4. Headphones that output sound to the left and right ears of the viewer, and direction detection means that is attached to the headphone or the head of the viewer wearing the headphones and that detects the orientation of the head of the viewer. A reflected sound adding unit that receives a sound signal and generates a sound signal by adding a reflected sound to a direct sound; a plurality of delay units that delays an output signal of the reflected sound adding unit by an arbitrary time; The output signal of the means is divided into a plurality of frequency bands, a plurality of sets of dividing means for controlling the output level of the divided signals, and the signals divided into the respective frequency bands of the dividing means are added, and the headphones are connected to the headphones. Output means for outputting, and control means for controlling the delay time of the delay means and the output level value of the dividing means respectively corresponding to each direction of the viewer's head detected by the direction detecting means. A headphone reproducing device characterized by being provided. 5. Headphones that output sound to the left and right ears of a viewer, and direction detection means that is attached to the headphone or the head of the viewer wearing the headphones and that detects the orientation of the head of the viewer. A plurality of calculation means for receiving a sound signal, performing a convolution calculation for localizing a sound image in an arbitrary direction, and generating a converted sound signal, and each direction of the viewer's head detected by the direction detection means Corresponding to, the first storage means for storing the coefficient of each convolution of the calculation means, and the reflected sound addition for receiving the signal of the calculation means and generating the acoustic signal in which the reflected sound is added to the direct sound. Means, second storage means corresponding to each direction of the viewer's head detected by the direction detecting means, and storing each creation data of the reflected sound of the reflected sound adding means, and detected by the direction detecting means. Corresponding to the direction , The convolution coefficient in the calculation means is read from the first storage means and set in the calculation means, and the created data in the reflected sound addition means is read from the second storage means and the reflected sound addition means. A headphone reproducing device, comprising: 6. Headphones that output sound to the left and right ears of the viewer, and direction detection means that is attached to the headphone or the head of the viewer wearing the headphones and that detects the orientation of the head of the viewer. A plurality of calculation means for inputting an acoustic signal and performing a convolution calculation for localizing a sound image in a specific direction, and a signal of the calculation means are input, and an acoustic signal in which a reflected sound is added to a direct sound is generated. Reflected sound adding means, a plurality of delay means for delaying the output signal of the reflected sound adding means by an arbitrary time, and dividing the output signal of the delay means into a plurality of frequency bands, and the output level of the divided signals A plurality of sets of dividing means for controlling the above, an adding means for adding the signals divided into the respective frequency bands of the dividing means, and outputting to the headphones, and a viewer detected by the direction detecting means. Corresponding to each direction of the parts, the headphone reproducing apparatus characterized by comprising a control means for respectively controlling the output level value of the delay time between the dividing means of said delay means. 7. The headphone according to claim 2, 4 or 5, wherein the reflected sound adding means generates a signal in which a reflected sound and a reverberant sound are added to the input direct sound. Playback device.