JP2000350299A - Sound signal reproduction device - Google Patents

Abstract

(57) Abstract: Provided is an audio signal reproducing device using a headphone device having a rotation angle detection function for preventing occurrence of a rotation angle detection error. SOLUTION: The sound signal reproducing device is a sound signal reproducing device for reproducing a multi-channel surround sound signal supplied from a signal source, and has a sound image forward by speakers 43 and 44 arranged in front of a listener 41. The surround sound signal is reproduced so that the sound image is localized behind by the first reproducing means for reproducing the surround sound signal so that the sound image is localized, and the headphones 12 capable of localizing the virtual sound image behind the listener 41. With the second reproducing means, an ideal surround sound field can be created even in a case where there is no space to arrange a speaker behind.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a headphone device having a rotation angle detecting function using an angular velocity sensor for reproducing an audio signal using headphones. More specifically, an object of the present invention is to provide an audio signal reproducing apparatus using a headphone device for the purpose of matching a sound image localization position of audio accompanying a video with a video position.

[0002]

2. Description of the Related Art Generally, an audio signal accompanying a video is reproduced from speakers placed on both sides of a display for reproducing the video, or speakers placed on the back of the screen when the video is projected on the screen. It is recorded assuming a reproduction state. Thereby, when the sound source in the video and the sound image position actually heard coincide with each other, a natural localization positional relationship between the video and the sound is established. However, when trying to appreciate the sound accompanying the video using conventional headphones, the sound image is not localized at the position of the sound source in the video ahead, but localized in the listener's head, and the sound source position in the video And the reproduced sound image localization position do not match, resulting in an extremely unnatural sound image localization relationship.

[0003] In order to improve this phenomenon, the applicant of the present invention considers that the audio reproducing apparatus, which the applicant of the present invention has applied for earlier, can reproduce the audio through a speaker even when listening to sound through headphones. To obtain an equivalent sound field, measure or calculate the impulse response from the speaker placed in front to both ears of the listener,
A method has been proposed in which this is convolved with an audio signal and then listened through headphones. According to this method, the sound image is not localized in the head, and a sound image very similar to the sound image reproduced by the speaker placed in front can be obtained. According to this method, the impulse response convolved with the audio signal can be updated at any time by detecting the rotational movement of the head of the listener wearing the headphones.

However, when an angular velocity sensor such as a piezoelectric vibrating gyroscope is used as a sensor for detecting the rotational motion,
A deviation may occur between the actual rotation angle and the measured value due to an integration error or a temperature drift during the angle calculation. For this reason, an error occurs in the detection of the rotational movement of the listener's head, and the positional relationship between the video and the sound image gradually shifts, which causes a problem that the reproduction of the video and the audio becomes unnatural.

[0005] To solve this problem, as shown in FIG. 7, if the direction in which the listener 71 faces the display 73 is the front direction 72, three
A method in which 60 degrees is set as the angle return range 74 and the detection reference direction of the rotational angular velocity sensor 75 for detecting rotational motion is returned to the front direction angle 72 at a constant speed over all the calculated angle return ranges 74 of 360 degrees. There is also.

However, according to this method, the return operation is performed even when the listener 71 is apparently facing a direction other than the display 73, for example, when the listener 71 faces backward at around 180 °. Will be. In this case, when the listener 71 goes to the display 73, that is, the front direction 72 after a while, the front direction 7
The direction 180 degrees behind 2 is the reference direction. For this reason, the return range from the direction 180 degrees behind to the front direction 72 is widened, and the detection error of the rotational movement of the head of the listener 71 is accumulated, and conversely, a large deviation occurs. There was a disadvantage that it would.

[0007]

As described above, the rotational angle of the head of the listener 71 is calculated using the rotational angular velocity sensor 75, and the sound image corresponding to the image position is reproduced using the headphones 76 based on the calculated angle. In this case, the output signal of the rotational angular velocity sensor 75 is integrated, and a deviation occurs between the image position and the sound image position due to an integration error in calculating the rotational angle. There is a problem that the sound image may be located in a positional relationship.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an audio signal reproducing apparatus using a headphone device having a rotation angle detecting function for preventing occurrence of a rotation angle detection error. .

[0009]

As shown in FIG. 4, the sound signal reproducing apparatus of the present invention is a sound signal reproducing apparatus for reproducing a multi-channel surround sound signal supplied from a signal source. A first reproducing means for reproducing a surround sound signal so that a sound image is localized forward by a first acoustic reproduction output unit arranged in front, and a second reproducing means capable of localizing a virtual sound image behind a listener And a second reproducing means for reproducing the surround sound signal so that the sound image is localized backward by the sound reproduction output unit.

In addition, as shown in FIG. 4, the audio signal reproducing apparatus according to the third embodiment reproduces a video signal corresponding to a surround sound signal by using a video reproduction output unit disposed in front of a listener. A reproducing means is provided.

Further, as shown in FIG. 4, in this audio signal reproducing apparatus, in the above description, the first audio reproduction output unit is at least two speakers, and the second audio reproduction output unit is headphones. is there.

Further, as shown in FIG. 4, in the acoustic signal reproducing apparatus according to the present invention, in the above, the headphones do not block external sounds. In addition, as shown in FIG. 4, in the acoustic signal reproducing device of the present invention, in the above description, the headphones detect the rotation angle of the listener with respect to the reference direction and localize the sound image in the back direction of the listener. And a rotation angle detecting means for updating the reproduction content of the reproducing means.

According to the present invention, an ideal surround sound field can be created by using the second sound reproduction output section even when there is no space to arrange a speaker behind.

Further, according to the present invention, an ideal surround sound field accompanying an image can be created.

According to the present invention, a clear rear surround sound field can be reproduced by headphones for reproducing a virtual sound field, and the main channel can be reproduced by a front speaker.

Further, according to the present invention, it is possible to simultaneously hear the sound image generated from the front speaker and the sound image generated rearward by the headphones. Further, according to the present invention, it is possible to reproduce a clear rear surround sound field using headphones that perform virtual sound field reproduction while localizing the sound image in the back direction of the listener.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a headphone device having a rotation angle detecting function applied to an audio signal reproducing apparatus according to the present invention. One embodiment of a headphone device having a rotation angle detection function applied to the audio signal reproducing device of the present invention is arranged such that when the listener is listening to the sound accompanying the image, the direction of the listener's head is in the image direction. In consideration of the fact that the image direction is often the front direction, when the rotation angle from the calculated front direction of the listener's head rotation angle is within the defined range, the front direction or A means for returning to another specified direction at a predetermined speed is provided.

FIG. 1 is a block diagram showing the configuration of an embodiment of a headphone device having a rotation angle detecting function applied to the audio signal reproducing device of the present invention. In FIG.
Headphones 12 to which the rotational angular velocity sensor 1 is attached
Has a rotational motion, the rotational angular velocity sensor 1 outputs a voltage proportional to the angular velocity. This signal is supplied to the amplifier 3 after being filtered by the band limiting filter 2. The amplifier 3 amplifies this signal, and the A / D converter 4
Supply to This signal is encoded by the A / D converter 4,
It is supplied to the microprocessor 5. The output signal of the A / D converter 4 supplied to the microprocessor 5 is sampled at fixed time intervals and supplied to the rotation angle calculation unit 6. Here, the input angular velocity signal is integrated and converted into angle data.

A rotation angle for actually localizing the sound image is calculated by the signal processing control unit 7 for returning the angle from the data, and the corresponding signal processing data is transferred to the digital signal processing device 9. In addition, an angle reset switch 14 is supplied to the rotation angle calculation unit 6 of the microprocessor 5 to determine the initial value of the rotation angle, whereby the rotation angle at the time when the reset signal is input is changed to the front direction angle (0).
°) or other prescribed angle, such as a rearward angle (180
°).

On the other hand, the audio signal supplied from the sound source 13 is encoded by the A / D converter 8 and supplied to the digital signal processor 9. The digital signal processing device 9 performs signal processing for localizing a required audio signal outside the head in accordance with the angle data calculated by the rotation angle calculation unit 6,
The result is supplied to the D / A converter 10. The audio signal returned to the analog signal again by the D / A converter 10 is supplied to a headphone 12 via a power amplifier 11 to give a listener who listens to the audio signal an optimal out-of-head localization signal. The rotation angle sensor 1 is, for example, a geomagnetic sensor or a vibration gyro attached to the headphones 14 for detecting the rotation angle of the head.

FIG. 2 shows an angle return operation of one embodiment of a headphone device having a rotation angle detecting function applied to the audio signal reproducing device of the present invention. In FIG. 2, a state in which the listener 21 faces the display 25 is referred to as a front direction. First, when the system is started, a reset signal from the angle reset switch 14 in FIG. 1 is supplied to the microprocessor 5 so that the front angle matches the image direction. The front direction 22 of the rotation angle calculated thereafter
If the deviation from the range is within the range of the angle return range 24, it returns to the front direction 22.

Therefore, the listener 21 is displayed on the display 25.
The return operation is performed so that the sound image direction coincides with the display 25 direction as long as the head movement is indicated while heading in the direction. Further, a range in which the listener 21 is apparently not facing the direction of the display 25, that is, the angle non-return range 23
When the rotation angle is indicated, the operation of resetting the calculated rotation angle is not performed. Thereby, when the listener 21 is intentionally directed outside the direction of the display 25, it is possible to avoid the occurrence of a shift between the video position and the sound image position due to the return operation.

As is apparent from the above description, the first embodiment has a signal processing device 9 for performing signal processing on a digitized audio signal, and a digital signal processed by the signal processing device 9. A D / A converter 10 for converting the signal into an analog signal of at least two channels, a power amplifier 11 for power-amplifying the signal, and an amplifier 11
And a headphone 12 driven by the
, An A / D converter 4 for converting the output into a digital signal, and a microprocessor for calculating the rotation angle from the front by taking in the A / D-converted digital data and performing integral calculation. And the signal processing device 9 according to the rotation angle.
In which the sound processing is updated so that the sound image is localized outside the head, wherein the rotation angle calculated by the microprocessor 5 is constant with respect to the front angle (0 °) 22. When the deviation is equal to or less than the angle, the angle in the front direction (0
°) to return to 22, and not to return if the angle deviation is larger than the above angle.

Therefore, according to the above example, when there is an image in the field of view of the listener 21, that is, when it is presumed to be watching the image, the rotation angle obtained by the calculation is the front angle (0 °) 22.
In order to perform the process to return to the above, the operation is performed to reduce the deviation between the video position and the sound image position. Conversely, if it is estimated that the listener 21 is not clearly facing the direction of the image, that is, if the rotation angle obtained by the calculation is more than a certain angle with respect to the front direction 22, the front direction angle (0 °) ) 22
And the occurrence of errors due to the return operation can be reduced.

FIG. 3 shows an angle return operation of another embodiment of a headphone device having a rotation angle detecting function applied to the acoustic signal reproducing device of the present invention. In FIG. 3, a state in which the listener 31 faces the direction of the display 36 is referred to as a front direction 32, similarly to FIG. Also,
A state in which the listener 31 faces 180 degrees with respect to the display 36 is referred to as a back direction 33. In FIG. 3, when the sound image direction coincides with the video direction, the operation is the same as that of the embodiment shown in FIG. That is, the deviation of the rotation angle from the front direction 32 due to the angle calculation is the front angle return range 34.
When the angle is within the range, the angle returns to the front direction 32. When the angle is outside the range, the angle return operation is not performed. When the sound image direction is set to the opposite side to the image direction, that is, the back direction 33, the angle is reset by the angle reset switch 14 in a state facing the back direction 33,
After that, the head is rotated in the front direction 32, and the angle set by the angle reset signal from the angle reset switch 14 is set in advance so as to be the rear direction angle (180 °).

As a result, in the initial state, the rotation angle roughly indicates the rear direction angle (180 °). Thereafter, when the deviation of the rotation angle from the front direction 32 by the angle calculation falls within the range of the angle non-return range 35, the rotation returns to the back direction 33. Not performed. Therefore, as long as the listener 31 shows the movement of the head while heading in the direction of the display 36, the sound image direction performs the return operation so as to be localized on the opposite side to the direction of the display 36. Further, when the listener indicates the rotation angle of the range in which the display 36 is apparently not facing the direction of the display 36, that is, the rotation angle of the back angle recovery range 35, the operation of resetting the calculated rotation angle is not performed. This allows the listener 31 to intentionally localize the sound image in the direction opposite to the display 36 intentionally.

In the second embodiment, the signal processing device 9 performs signal processing on the digitized audio signal, and converts the digital signal processed by the signal processing device 9 into an analog signal of at least two channels. D / A
Converter 10 and power amplifier 11 for power amplifying this signal
And a headphone 12 driven by the amplifier 11
And an angular velocity sensor 1 attached to the headphone 12, an A / D converter 4 for converting the output into a digital signal, and an A / D converted digital data. And a microprocessor 5 for calculating the following formula: ## EQU1 ## wherein the content of the signal processing in the signal processing device 9 is updated in accordance with the rotation angle so that the sound image is localized outside the head. When the rotation angle from the front direction calculated by the microprocessor 5 is a plurality of reference angles, that is, a deviation of a predetermined angle or less with respect to the front direction 32 and the back direction 33, the reference angle closest at a predetermined speed. And does not return if the angle deviation is larger than the above angle.

Therefore, according to the above example, if a sound image, such as a reverberant sound, which is to be localized behind the listener 31 is set to the rearward angle (180 °) 33 in the initial state, the sound image is stably rearward thereafter. Can be localized.
By applying this to a surround system, an ideal surround sound field can be provided even in an environment where a speaker cannot be laid out behind.

FIG. 4 shows an example in which a headphone device having a rotation angle detecting function applied to the audio signal reproducing apparatus of the present invention is applied to a multi-channel surround sound field system of another embodiment. In FIG. 4, a display 42 is arranged in front of a listener 41, and speakers 43 and 44 are arranged on both left and right sides of the display 42. Behind the listener 41, a sound image 45 is provided at a position where a rear speaker is originally arranged.
A four-channel surround sound field system is configured such that 46 is localized. In this case, the channel to be supplied to the rear speaker is, as shown in FIG. 3, a sound signal provided to the headphone device having a rotation angle detecting function applied to the acoustic signal reproducing device of the present invention for localizing the sound image in the rear direction. Supply signal.

The channels to be supplied to the front speakers 43 and 44 are supplied to the front speakers 43 and 44 as they are. Thereafter, as shown in FIG. 3, the sound signal of the headphone device having the rotation angle detecting function of the present invention for localizing the sound image in the back direction is listened to by the open air type headphone, and this sound image is rearward, that is, the sound image 45, the sound image. 46 can be generated. Since the open-air headphones can separate the left and right headphone units from both ears of the listener 41 with the support member and can input external sound to both ears without blocking them, the sound image generated from the front speaker and the headphone can be input. Can simultaneously hear the sound image generated backward, and this third
According to the embodiment, an ideal surround sound field can be created even in a case where there is no space for disposing a speaker behind.

FIG. 5 shows an angle return operation of another embodiment of a headphone device having a rotation angle detecting function applied to the audio signal reproducing device of the present invention. In the fourth embodiment, an identification range of the angle return speed is provided, and the angle return speed is changed according to this range. In FIG. 5, when the system of the headphone device having the rotation angle detecting function of the present invention is started, an angle reset signal from the angle reset switch 14 shown in FIG. Match. Thereafter, when the calculated angle of the rotation angle with respect to the front direction 52 is within the range of the angle return range 53, the sound image returns to the front direction 52 at such a low speed that the movement of the sound image cannot be detected. In other rotation angle ranges, the return operation is performed in the front direction 52 at a relatively high speed until the angle range of the angle return range 53 is entered. FIG.
10 shows how the return speed changes in another embodiment of the headphone device having a rotation angle detection function applied to the audio signal reproducing device of the present invention. As shown in FIG. 6, the return speed is set to be slower within the angle return speed identification range, and is set to be faster outside the angle return speed identification range.

In the fourth embodiment, the return speed for returning to the specified angle is varied according to the value of the rotation angle calculated by the microprocessor 5.
Therefore, according to the above example, the angle near the front direction 52 as the return target value, that is, the angle return speed identification range 53
In this case, the return speed is slowed down, making it difficult for the listener 51 to recognize the movement of the sound image due to the angle return operation with respect to the change, and the vicinity of the angle which is the front direction 52 as the return target angle, that is, from the angle return speed identification range 53 When the vehicle is far away, the return speed can be increased so that the head moves in the direction in which the displacement returns quickly, so that the time required to recover to a normal sound image localization position can be shortened when the direction is largely shifted.

[0033]

According to the sound signal reproducing apparatus of the present invention, in a sound signal reproducing apparatus for reproducing a multi-channel surround sound signal supplied from a signal source, a first sound reproduction output disposed in front of a listener. First reproducing means for reproducing the surround sound signal so that the sound image is localized in the front, and a second reproducing means capable of localizing the virtual sound image behind the listener.
And a second reproducing means for reproducing the surround sound signal so that the sound image is localized at the rear by the sound reproducing output unit of the second embodiment. An ideal surround sound field can be created using the sound reproduction output unit.

[0034] In the above-described audio signal reproducing apparatus of the present invention, the third reproducing means for reproducing the video signal corresponding to the surround sound signal by the video reproduction output section arranged in front of the listener is provided. Therefore, an ideal surround sound field accompanying the image can be created.

Further, in the acoustic signal reproducing apparatus of the present invention, since the first sound reproducing output section is at least two speakers and the second sound reproducing output section is headphones, the sound signal reproducing apparatus reproduces the virtual sound field. A clear rear surround sound field is reproduced by headphones to be performed, and the main channel can be reproduced by a front speaker.

Further, in the acoustic signal reproducing apparatus of the present invention, since the headphone does not block external sound in the above, the sound image generated from the front speaker and the sound image generated rearward by the headphone are simultaneously heard. can do.

Further, in the acoustic signal reproducing apparatus according to the present invention, in the above, the headphone detects the rotation angle of the listener with respect to the reference direction so as to localize the sound image in the back direction of the listener. Since the rotation angle detecting means for updating the reproduction content is provided, a clear rear surround sound field can be reproduced by headphones for reproducing the virtual sound field while localizing the sound image in the back direction of the listener.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a headphone device having a rotation angle detecting function applied to an audio signal reproducing device of the present invention.

FIG. 2 is a diagram showing an angle return operation of one embodiment of a headphone device having a rotation angle detection function applied to the audio signal reproducing device of the present invention.

FIG. 3 is a diagram showing an angle return operation at a plurality of return positions in another embodiment of the headphone device having a rotation angle detection function applied to the acoustic signal reproducing device of the present invention.

FIG. 4 is a diagram showing an example applied to a multi-channel surround sound field system of another embodiment of a headphone device having a rotation angle detecting function applied to the audio signal reproducing device of the present invention.

FIG. 5 is a diagram showing an angle return operation for changing a return speed of another embodiment of the headphone device having a rotation angle detection function applied to the audio signal reproducing device of the present invention.

FIG. 6 is a diagram showing a state of a change in a return speed of another embodiment of a headphone device having a rotation angle detecting function applied to the audio signal reproducing device of the present invention.

FIG. 7 is a diagram showing an angle return operation of the headphone device previously filed by the applicant of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotation angular velocity sensor, 2 ... Band limiting filter, 3 ... Amplifier, 4,8 ... A / D converter, 5 ...
..Microprocessor, 6 ... rotation angle calculation unit, 7
... Signal processing control unit, 9 ... Digital signal processing device, 10 ... D / A converter, 11 ... Power amplifier,
12 headphone, 13 sound source, 14 angle reset switch, 21 listener, 22 frontal direction (0 °), 23 angle non-return range, 24
・ Angle return range, 25 ・ ・ ・ Display, 31 ・ ・ ・
Listener, 32: Front direction (0 °), 33: Back direction (180 °), 34: Front angle return range, 35
... Back angle return range, 36 ... Display, 4
1 ... listener, 42 ... display, 43, 44
... Speaker, 45 ... Sound image, 46 ... Sound image, 5
1 · · · listener · 52 · · · front direction (0 °) · 53 ·
..Angle return speed identification range, 54 ... Display

Claims (5)

[Claims] 1. A sound signal reproducing apparatus for reproducing a multi-channel surround sound signal supplied from a signal source, wherein a sound image is localized forward by a first sound reproduction output unit disposed in front of a listener. Means for reproducing the surround sound signal as described above, and a second sound reproduction output unit capable of localizing a virtual sound image to the rear of the listener so that the surround sound is localized to the rear. An acoustic signal reproducing device comprising: a second reproducing unit that reproduces a signal. 2. The sound according to claim 1, wherein a third reproduction means for reproducing a video signal corresponding to the surround sound signal is provided by a video reproduction output section disposed in front of the listener. Signal playback device. 3. The audio signal reproducing device according to claim 1, wherein the first audio reproduction output unit is at least two speakers, and the second audio reproduction output unit is a headphone. 4. The audio signal reproducing apparatus according to claim 3, wherein said headphones do not block external sounds. 5. The headphone further comprises a rotation angle detecting means for detecting a rotation angle of the listener with respect to a reference direction and updating a reproduction content of the second reproduction means so as to localize the sound image in a direction toward the back of the listener. The audio signal reproducing device according to claim 3, comprising: