JP2002291100A - Audio signal reproducing method, and package media - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an audio signal reproducing method that can exclude the effect of a reflection sound and a reverberation sound in a room. SOLUTION: In the audio signal reproducing method to reproduce multi-channel audio signals, the audio signal of each channel is shared into left and right output signals to localize the sound image in a way that a listener can hear the sound in a sense of distance and in a sense of direction equivalent to those of reproduction of the audio signal of each channel by the arrangement of the loud speakers in a normal multi-channel and the left and right output signals are supplied to the loud speakers 21, 22 respectively placed in the vicinity of the left and right auricles of the listener.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a personal multi-channel audio reproducing method, and more particularly to an audio reproducing method capable of eliminating (removing) the effects of reflected sound and reverberant sound in a room.

[0002]

2. Description of the Related Art In a conventional audio signal reproducing apparatus, speakers are arranged at a certain distance in a direction in which a reproduced sound arrives, and the reproduced sound is heard.

For example, in the case of two-channel stereo reproduction, speakers are arranged in front of a listener, and in the case of surround reproduction, speakers corresponding to surround channels are arranged in addition to the side and rear to listen to those sounds.

A configuration of an example of a conventional audio signal reproducing apparatus will be described with reference to the drawings. An example of the audio signal reproducing apparatus shown in FIG. 8 is disclosed in Japanese Patent Application Laid-Open No. 8-265899. The audio signal reproducing device transmits the 5ch signal from the demodulator 101 to the speakers 103L, 10L arranged at symmetrical positions in front of the listener.
The left and right sound image localization filters 121a and 121b in which coefficients based on the head-related transfer function are set for each channel of the rear surround signals SL and SR as the signal processing means 102 for reproducing from the 3R, and the same right and left sound image localization It has filters 121c and 121d.

Further, adders 121f and 121g for adding the center channel signal C via the attenuator 121e to the front stereo signals L and R, and the output signal of the adder 121f to the output signal of the left sound image localization filter 121a and the right sound image. An adder 121h that adds the output signal of the localization filter 121c, and similarly, an adder 121 that adds the output signal of the right sound image localization filter 121b and the output signal of the left sound image localization filter 121d to the output signal of the adder 121g.
i.

With the above configuration, the demodulator 10 shown in FIG.
Among the 5ch signals demodulated and separated from 1, the two-channel stereo signals L and R are provided via adders 121f to 121i to stereo speakers 103L and 103R such as a television or the like arranged at a position substantially symmetrical to the listener in front of the listener. Is reproduced as it is. After the level of the center channel signal C is reduced by 3 dB through the attenuator 121e, the loudspeaker 103 is added through the adders 121f to 121i.
L and 103R.

The rear surround signals SL and SR are
Atarschrader (ATAL-SCHROEDER)
Pair of left and right sound image localization filters 121a and 121b, and 121c and 121 using a type of filter.
Processing is performed so that the sound image is localized on the left and right sides of the listener via d, respectively, and is added to the front two-channel stereo signals L and R via adders 121h and 121i. Therefore, the listener can enjoy the moving sound while being surrounded by the sound image of 5ch while watching the television in front. Particularly, since the rear surround signals SL and SR are separate signals, a high sense of reality can be obtained.

This is a surround signal processing apparatus for reproducing all five discrete channels by a pair of speakers 103L and 103R arranged at symmetrical front positions. The pair of left and right speakers 103L and 103R are ordinary large main speakers, and are arranged with a space in front of the listener. The reproduced sound from the pair of left and right speakers 103L and 103R disposed at the front position includes the reflected sound and reverberation sound of the room and is heard by the listener.

[0009]

(1) Left and right speakers 1 arranged at a distance (space) around a listener
The sound reproduced from 03L and 103R reaches the ear with the reflection sound and reverberation sound of the place added. That is, the recorded sound does not reach the ear as it is, but the sound peculiar to the room always accompanies and hinders the reproduction of the original sound.

(2) In order to construct a surround playback system such as a home theater, a certain amount of room is required, and a number and power corresponding to the number of channels, such as speakers and amplifiers, are required. You will be restricted.

[0011]

To solve the above problem (1), the influence of the reflected sound and reverberation sound in the room is eliminated by disposing the reproduction speaker close to the listener and placing it near both auricles. A new problem arises in that the sound reproduced from each speaker reaches the ear directly, and at the same time, the sense of distance and sense of direction of the reproduced sound is different from the case where the sound is heard with a normal speaker arrangement. Is solved by processing the signals of the respective channels by a DSP so that the signals can be heard with the same sense of distance and sense of direction as those reproduced by the conventional speaker arrangement. With regard to signal processing of each channel, processing is performed to give a characteristic corresponding to an acoustic transfer function from each speaker to the vicinity of the pinna of the listener, not the ear hole of the listener, in a conventional speaker arrangement.

Regarding the problem (2), since two speakers and an amplifier can be realized with two channels and the distance between the ear and the speaker is short, the reproduction sound pressure required for the speaker is small. The problem is solved by using a small speaker and a small amplifier, eliminating the need for large power and eliminating the need for a rear space for surround.

[0013] Therefore, in order to solve the above-mentioned problem, the invention described in claim 1 provides a multi-channel speaker processed to be supplied to a multi-channel speaker arranged at a distance around a listener. Audio signal
In the audio signal reproducing method of reproducing with the small two speakers without using the speakers having the above arrangement, the small two speakers are arranged near the left and right pinna of the listener, respectively.
The audio signal of each channel is processed so as to have a characteristic corresponding to a left and right acoustic transfer function from each speaker in the multi-channel arrangement to the vicinity of the left and right pinna, and the audio signal of each channel is processed. An audio signal reproducing method, comprising: distributing left and right signals; supplying the divided left and right signals to the two small speakers; and localizing a sound image as if each speaker were located at the speaker position of the multi-channel arrangement. The present invention according to claim 2 provides a package medium in which a multi-channel audio signal is recorded, together with a normal multi-channel audio signal,
An object of the present invention is to provide a package medium characterized by recording an output signal obtained by subjecting a reproduced signal of the multi-channel audio signal to signal processing by the audio signal reproducing method according to claim 1.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an audio reproducing apparatus to which the audio reproducing method of the present invention is applied will be described below with reference to the drawings.

In the embodiment of the present invention shown in FIG. 1, a left channel (Lch) input circuit 1, a center channel (Ce)
nter ch) input circuit 5, right channel (Rch)
Input circuit 2, surround left channel (SLch) input circuit 3, surround right channel (SRch) input circuit 4, reduction (3 dB) circuit 6, adder circuits 7, 8, left front localization function circuit 11, right front localization function circuit 12 , Left rear localization function circuit 13, right rear localization function circuit 14, Lch addition circuit 15, Rch addition circuit 16, Lch reproduction circuit 1
7, Rch reproduction circuit 18, Lch small speaker 2
1 and a small speaker 22 for Rch.

There is already a speaker such as a body sonic in which a speaker is arranged behind a listener, and it is known that, when a binaural recording source is to be listened to by a speaker, it can be quite effective to place the binaural recording source in the left or right direction of the listening position. In the present invention,
An object of the present invention is to provide an audio reproduction signal reproducing method in which the arrangement of the left and right pinnae of the listener of the speaker is combined with a signal processing method of sound image localization of the reproduction signal.

Another object of the present invention is to provide a package medium in which a reproduction signal subjected to the signal processing of the present invention is recorded simultaneously with a normal audio reproduction signal.

The acoustic transfer function (FL) circuit and acoustic transfer function (FR) circuit constituting the sound image localization function circuit according to the present invention will be described below. A small microphone (not shown) is placed in the vicinity of the ear pinna of the listener, and the reproduced sound from each speaker is measured to set each transfer function (circuit). As shown in FIG. 7, “near the pinna” indicates a position 1 cm to 3 cm away from the entrance outward.

Naturally, the so-called head-related transfer function in which a microphone is placed at the position of the ear canal or the eardrum has characteristics different from those of the head-related transfer function in which the microphone is placed at the position of the pinna. In fact, instead of using real human heads, they use dermy heads and dummy pinna. In order to emphasize the feature of the dummy pinna more than the real pinna, the dummy pinna is a combination of a larger earlobe-equivalent part and a parabolic antenna-like reflector (not shown).

The function of each function (circuit) will be described below. Hereinafter, for a function circuit X that generates a function, the function is described as XF. The sound image localization function (the circuit thereof) is, for example, a left front sound image localization function 11F (the circuit 11) thereof.
By performing (circuit) processing on the input signal with the characteristics of this function 11F (the circuit 11), the left channel (L
It has a function of performing (circuit) processing to be heard by a listener as if the speaker 41 is at the position of (ch).

Similarly, the right front sound image localization function 12F, the left rear sound image localization function 13F, and the right rear sound image localization function 14F are similar to each other, and the speaker 42 is positioned at the right channel (Rch) in FIG. The speaker 43 is located at the position of (SLch), and the right rear channel (SRch)
Has a function of performing a process of sounding as if there is a speaker 44 at the position of.

The characteristics of each function will be described below with reference to FIG. As an example, the left front sound image localization function 11F (the circuit 11) will be described. Right front sound localization function 12
F, left rear sound image localization function 13F, right rear sound image localization function 1
The function (the circuit) can be obtained for 4F in the same manner.

In FIG. 2, an acoustic transfer function (circuit thereof) until the sound output from the left front speaker 41 reaches the vicinity of the left and right pinna, including the reflected sound and reverberant sound of the space, is
The acoustic transfer function 11LF (the circuit 11L) and the acoustic transfer function 11RF (the circuit 11R) are provided. These functions can be obtained by measurement by placing a small microphone near the pinna and reproducing a predetermined signal from a speaker. Further, these functions can be obtained by theoretical calculation. Here, the acoustic transfer function 11
F (the circuit 11) has an acoustic transfer function 11LF (the circuit 11L) and an acoustic transfer function 11RF (the circuit 11R).

Since the characteristics of the obtained transfer function can be realized by a DSP, the input signal may be processed by the DSP. After all, the contents of the left front sound image localization function 11F (the circuit 11) include the input signal as the acoustic transfer function 11LF.
It can be said that the circuit (the circuit 11L) and the sound transfer function 11RF (the circuit 11R) are functions (circuits) that can be divided into two systems of Lch and Rch.

The signal processing and the reproduction characteristics by each function (circuit) will be described. The reproduced Lch signal in FIG. 1 is supplied to the Lch input circuit 1 and the above-described acoustic transfer function 11
The signal is processed by the (characteristic) circuit of the LF (its circuit 11L) and reproduced from the Lch speaker 21, and the sound transfer function 11R
The signal is processed by the (characteristic) circuit of F (the circuit 11R) and reproduced from the Rch speaker 22.

The Lch and Rch speakers 21 and 22 placed near the pinna of the listener create a sound field having the same relation as that at the time of measurement near the pinna, so that the speakers 21 and 22 are arranged as shown in FIG. Despite being near the ear pinna of the listener, the sound is perceived to be heard from the position of the virtual speaker 41 in the conventional speaker arrangement on the left front.

This is the processing by the left front sound image localization function 11F (the circuit 11). Similarly, for the other ch signals, the right front sound image localization function 12F and the left rear sound image localization function 1F are also used.
It is possible to perform (circuit) processing by 3F and the right rear sound image localization function 14F.

However, the Center ch is attenuated by 3 dB in the 3 dB reduction circuit 6 and added to the left and right signals by the addition circuits 7 and
The signal is mixed at 8 and treated as left and right signals. When this signal is reproduced, since it is a signal of the same level in the left and right, it can be heard from the position of the center virtual speaker 45 as a Center sound as in conventional stereo reproduction. .

As a result, as shown in FIG. 1, as a whole system, a plurality of temporary speakers 41 to 41 indicated by wavy lines are displayed.
The sound source of each channel can be perceived at a position such as 44. In a conventional 2-channel stereo, a surround sound field can be perceived in a forward direction and in a 5-channel DVD, a perceptible reproduction can be performed. The multi-channel audio signal of the present invention is 5ch
However, the present invention can be applied to a two-channel audio signal supplied to a speaker having a two-channel stereo arrangement. Since the pair of left and right speakers are arranged near the pinna, unlike the case of playback using headphones, the playback sound does not feel as if it is going upward, and the sound field is a natural sound with a localized sound field. Easy to hear.

Next, an embodiment of the package medium (recording medium) of the present invention will be described below with reference to the drawings. FIG. 3 shows an embodiment of the package medium of the present invention. As shown in FIG. 3, a normal multi-channel audio signal is recorded in an area 20P inside the package medium 20A,
It is assumed that an output signal obtained by processing the (reproduced signal of) the multi-channel audio signal by the audio signal reproducing method of the present invention is recorded in the area 20Q outside A.

In the present invention shown in FIG. 3, in a package medium 20A in which a multi-channel audio signal is modulated and recorded, a reproduction signal of the multi-channel audio signal is described together with a normal multi-channel audio signal. This is a package medium 20A in which a reproduced output signal processed by the audio signal reproducing method of the present invention is modulated and recorded.

In this case, the package medium 20A
-Channel audio playback device 31A on which is mounted
In this case, the signal processed by the method of the present invention, which is recorded in the area 20Q, is selected, and the demodulated and reproduced two-channel reproduced signal may be directly supplied to the left and right speakers 21 and 22. The playback device 31A that plays back the package medium 20A does not need to include the sound image localization signal processing circuit 10, and an ordinary circuit is sufficient. Incidentally, if the area 20P of the package medium 20A where the normal multi-channel audio signal is recorded is selected, it can be enjoyed with a normal audio reproducing device.

The case where the audio data of the present invention is distributed by a transmission medium (medium) will be described below. The present invention relates to a transmission medium for modulating a multi-channel audio signal and transmitting a reproduction signal of the multi-channel audio signal together with a normal multi-channel audio signal by the audio signal reproduction method according to claim 1. This is a transmission medium having audio data obtained by modulating a reproduced output signal subjected to the above.

The transmission medium of the present invention is distributed through the Internet. The listener receives the audio data at the receiving terminal, and reproduces the reproduced audio data via a small amplifier in the vicinity of the left and right pinna of the pair of left and right listeners. The multi-channel sound image can be reproduced as localized sound from the small speakers respectively arranged in the speakers, and can be heard without taking up space.

A large-screen personal theater system and a PC personal system to which the present invention is applied are shown below with reference to the drawings. FIG. 4 shows an embodiment of a large-screen personal theater system to which the present invention is applied, and FIG.
FIG. 5 shows an embodiment of a personal theater system, and FIG. 6 shows an embodiment using a pole speaker to which the present invention is applied.
Are shown below.

FIG. 4 shows an embodiment of a large-screen personal theater system to which the present invention is applied. A large-screen screen 51 is installed on a front wall, for example, on a wall, and a listener located at the front center of the screen 51 is shown. The left and right speakers 21 and 22 installed near the auricles are 8 cm to 12 mm in diameter.
A single cone type of cm is optimal, and the height of the installation is adjusted to the height of the pinna. The presence of the omnidirectional surround sound field and powerful reproduction can be achieved only by the two left and right speakers 21 and 22. The signal processing circuit 10 supplies a signal obtained by subjecting the reproduced signal from the player 31 to sound field processing to the speakers 21 and 22. However, if the signal subjected to the sound field processing is obtained from the disc 20A, there is no need to perform the sound field processing. 2 channel reproduction circuit may be used.

FIG. 5 shows an embodiment of a PC personal theater system, in which a display 51 is provided at the center, speakers 21 and 22 are embedded in the back of a chair, and a detachable system is also conceivable. Since it is close to the ear, it does not need to be highly efficient. Therefore, it is possible to aim for a wide range with a small size and high performance, or supplement the bass with the subwoofer 46.

FIG. 6 shows an embodiment in which bass sounds are supplemented by a subwoofer 46 in which pole speakers 21 and 22 are used.
The subwoofer 46 is installed under a chair (not shown) on which the listener sits. Reproduction signals are supplied from the sound image localization signal processing circuit 10 to the pole speakers 21 and 22, respectively, and reproduction signals are supplied to the subwoofer 46 from the signal processing circuit 52 that has performed low-frequency processing.

The reproduced sound according to each of the embodiments described above can be felt very naturally because there is no peculiar inversion that occurs in the case of a system in which a speaker is placed in front, such as 3D phonic. Since there is no influence of the acoustic characteristics of the listener's room, the sound field at the recording site is reproduced exactly. Therefore, even in the case of Hi-Fi reproduction, this system can be said to be the ultimate system that is close to ideal.

[0040]

According to the first aspect of the present invention, a multi-channel audio signal processed to be supplied to a multi-channel speaker arranged at a distance around a listener is supplied to the arrangement. In the audio signal reproducing method of reproducing by the small two speakers without using the speakers, the small two speakers are respectively arranged near the left and right auricles of the listener, and the multi-channel arrangement is performed on the audio signal of each channel. Of the respective channels to the left and right signals by performing processing for giving characteristics equivalent to the left and right acoustic transfer functions from each speaker to the vicinity of the left and right pinna. Is supplied to each of the two small speakers, and the sound is produced as if each speaker were at the speaker position of the multi-channel arrangement. Since localizing and eliminating the effects of reflected sound and reverberation room, since the reproduced sound of each speaker can be so as to reach the ear directly, albeit at a personal, can provide a very high quality audio reproduction method.

According to the first aspect of the present invention, there is no need for a specially sound-processed room, and there is no need to arrange speakers at a distance around the listener. It is sufficient that there is a space for placing two small speakers near the pinna of the user. Both the front space and the rear space for surround can be eliminated, and reproduction can be performed without taking up space (place), and space can be saved.

According to the first aspect of the present invention, since the pinna and the speaker are close to each other and the distance between the pinna and the speaker is short, the reproduction sound pressure required for the small speaker becomes small,
A small speaker and a small reproduction amplifier can be used, and the power consumption is reduced, which is efficient.

According to the first aspect of the present invention, the sound transfer function is determined not based on the ear hole portion where the individual difference is likely to occur, but on the basis of the vicinity of the pinna. Can be

According to the second aspect of the present invention, in a package medium on which a multi-channel audio signal is recorded, a reproduction signal of the multi-channel audio signal is reproduced together with a normal multi-channel audio signal. Since the output signal subjected to signal processing according to the described audio signal reproducing method is recorded, a reproducing speaker is arranged near both ears of the listener, thereby eliminating the influence of the reflected sound and reverberant sound in the room. The playback sound of the speaker can directly reach the auricle, and it is possible to provide a package medium that is personal but capable of playing back extremely high quality audio.

According to the second aspect of the present invention, there is provided a package medium capable of performing the same reproduction as that of a normal multi-channel speaker by using a reproducing apparatus having a simple configuration and a pair of small speakers. I can do it.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of an audio signal reproducing apparatus to which an audio signal reproducing method of the present invention is applied.

FIG. 2 is a diagram illustrating a signal processing method for sound image localization in the audio signal reproducing method according to the present invention.

FIG. 3 is a diagram showing a configuration of an embodiment of the package medium of the present invention.

FIG. 4 is a diagram showing a configuration applied to a theater hi-fi system of an embodiment of an audio reproducing apparatus to which the audio reproducing method of the present invention is applied.

FIG. 5 is a diagram showing a configuration applied to a theater hi-fi system of an embodiment of an audio reproducing apparatus to which the audio reproducing method of the present invention is applied.

FIG. 6 is a diagram showing a configuration applied to a theater system of an embodiment of an audio reproducing apparatus to which the audio reproducing method of the present invention is applied.

FIG. 7 is a diagram showing a configuration of a pinna portion of a listener on which a speaker is arranged by the audio reproducing method of the present invention.

FIG. 8 is a diagram showing a configuration of an example of a conventional audio signal reproducing device.

[Explanation of symbols]

1 left channel (Lch) input circuit 2 right channel (Rch) input circuit 3 surround left channel (SLch) input circuit 4 surround right channel (SRch) input circuit 5 center channel (Center ch, Cch) input circuit 6 reduction (3 dB) Circuit 7, 8 Addition circuit 10 Sound image localization signal processing circuit 11 Left front localization function (circuit) 11F Left front localization function 11L Sound transfer function (FL) (circuit) 11R Sound transfer function (FR) (circuit) 12 Right front localization function Circuit 12F Right front localization function 13 Left rear localization function circuit 13F Left rear localization function 14 Right rear localization function circuit 14F Right rear localization function 15 Lch addition circuit 16 Rch addition circuit 17 Lch reproduction circuit 18 Rch reproduction circuit 20 Package Media (recording medium, disk) 20A of the present invention Package medium (recording medium, disk) having recording area of output signal processed by reproduction method 20P Recording area of normal multi-channel audio signal 20Q Recording area of output signal processed by reproduction method of the present invention 21 Left channel (Lch) Small speaker 22 Small speaker for right channel (Rch) 31, 31A Player (DVD player) 41 Virtual speaker for left channel (Lch) 42 Virtual speaker for right channel (Rch) 43 Surround virtual speaker for left channel (SLch) 44 Surround Virtual speaker for right channel (SRch) 45 Virtual speaker for center (Cch) 46 Subwoofer 51 Display device (screen, display) 52 Signal processing circuit (bass)

Claims (2)

[Claims] A multi-channel audio signal processed to be supplied to a multi-channel speaker arranged at a distance around a listener without using the speaker arranged in the small-sized two-speaker. In the audio signal reproducing method, the small two speakers are respectively arranged near the left and right pinna of the listener, and the audio signal of each channel reaches the vicinity of the left and right pinna from each speaker of the multi-channel arrangement. Processing to give characteristics corresponding to the left and right sound transfer functions until the audio signal of each channel is divided into left and right signals, and the divided left and right signals are supplied to the small two speakers, respectively. The sound image is localized as if each speaker is located at the speaker position of the multi-channel arrangement. I o signal reproduction method. 2. A package medium in which a multi-channel audio signal is recorded, wherein a reproduction signal of the multi-channel audio signal is output together with a normal multi-channel audio signal by the audio signal reproduction method according to claim 1. A package medium characterized by recording an output signal subjected to processing.