JP2885138B2 - Sound reproduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound reproducing apparatus for reproducing a soundtrack sound of movie software produced on the premise that it is reproduced in a movie theater in a general home environment, and more particularly to a sound reproducing apparatus having a flat audibility. Characteristic can be set so that the soundtrack sound of these movie software can be heard with a more optimal frequency characteristic balance.

[0002]

2. Description of the Related Art Soundtrack creation (sound design) of a movie to be shown in a movie theater is carried out in a dedicated studio (dubbing stage) created in the same manner as an actual movie theater while actually listening to the sound. In sound design, it is required to make sound so that the audience can feel that the frequency characteristics are flat in terms of hearing when reproduced in an actual movie theater. However, if an audio signal recorded with flat characteristics is reproduced as it is in a large venue such as a movie theater, even if a flat characteristic is obtained by actual measurement using a measuring instrument, etc., the high frequency range will be more emphasized in terms of auditory perception. A phenomenon occurs that sounds as if the region characteristic has increased. This is because, in a large venue, the sound source is far from humans, and the sound field is such that the ratio of the reflected sound from the side increases in addition to the direct sound from the front, and the sound field is diffused as a whole. That is, due to its structure, the human ear has a high-frequency sensitivity that increases with respect to sound coming from a direction that is straight into the ear canal, so the reflected sound from the high-frequency sensitivity direction is almost equal to the direct sound. The higher the frequency, the higher the frequency will be.
In addition, when listening in a home environment, since a sound source is close to a speaker at hand, almost direct sound is dominant, and almost no high-frequency rise as in the above-described reproduction in a movie theater occurs. In consideration of being used as a common source sound, it is necessary to devise a way to make it possible to listen in the same way when playing in a movie theater and in a home environment.

[0003] In order to switch between a flat source sound to be heard through a speaker at hand and the sound of equipment in a large venue such as a movie theater and to hear these sounds equally,
At cinema venues, it has been empirically corrected to the characteristic of a high-frequency drop called the house curve. This is called the X curve (see FIG. 2) relating to the sound characteristics of the movie theater established as ISO-2969.
Based on this ISO-2969, the dubbing stage and the actual movie theater are designed so that the measured frequency characteristics become an X-curve, and the software produced therefrom has a flat characteristic in terms of audibility when reproduced in the movie theater ( However, if measured with a measuring instrument, the characteristic that the high frequency is attenuated according to the X curve) can be obtained.

[0004]

The reverberation time of modern movie theaters and, at the same time, the dubbing stage where sound is designed, is shorter than when the above-mentioned X-curve was established. Originally, the X-curve stipulates that in a space having a long reverberation time, that is, a large ratio of a diffuse sound field, attenuation at a higher frequency is required. However, in a short space, it means that the attenuation of the high frequency band should be less. However, at the time of the establishment of the X-curve, it was hardly assumed that the reverberation time would be as short as in modern times.
The X curve based on O-2969, on average,
It is likely that the highs are too low for modern cinemas and soundstages. However, both the movie theater and the sound stage are in the same environment,
Further, since the applied X-curve is the same, as far as the reproduction in the movie theater is concerned, the reproduction made as intended by the sound stage is possible, and there is no problem on the surface.

[0005] However, a problem occurs at the time of reproduction in a home environment space which is not a diffuse sound field like a movie theater. That is, in the sound stage, the sound is made so that the sound is heard to be flat in a state where the high frequencies are attenuated based on the X curve described above. At this time, the ratio of the diffused sound field in this sound stage, That is, the amount of the side reflected sound is not large enough to realize the high-frequency rise to be corrected by the X curve, and in this state, when the source sound is reproduced with flat characteristics, the audibility at the sound stage is reduced. Since the highs still seem to be low, the highs are raised so that they sound flat during the sound-making stage. As a result, the produced soundtrack sound has a higher frequency region emphasized compared to the original flat characteristic. When such a soundtrack sound is reproduced in a general home environment, the high-frequency emphasis appears almost as it is, which is unnatural.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and easily reproduces soundtrack sound of movie software produced on the premise of being reproduced in a movie theater in a general home environment. It is an object of the present invention to provide an audio reproducing apparatus which can set a flat characteristic in terms of audibility and can listen to the soundtrack sound of the movie software with a more optimal frequency characteristic balance.

[0007]

According to the first aspect of the present invention,
An input terminal to which the playback audio signal of the movie software produced on the assumption that it will be played in a movie theater is input, and a dedicated equivalent circuit for correcting the frequency characteristics of the playback audio signal of the movie software from this input terminal And its amplitude characteristic linearly attenuates toward high frequencies starting from 2 kHz and becomes 1
And equivalent filter means having equivalent characteristics such as −2 dB ± 1 dB at 0 kHz.

According to a second aspect of the present invention, there is provided an input terminal to which a reproduced audio signal of movie software or a reproduced audio signal of other video or audio software produced on the premise of being reproduced in a movie theater is inputted, This is a dedicated equivalent circuit for correcting the frequency characteristic of the reproduced audio signal of the movie software, wherein the amplitude characteristic is linearly attenuated toward a high frequency starting from 2 kHz and becomes −2 dB ± 1 dB at 10 kHz. Equivalent filter means, movie software playback instruction operating means for instructing the playback of movie software, and when the playback of the movie software is instructed by the movie software playback instruction operating means, Initial setting is made so that the frequency characteristics are corrected by the equivalent filter through the equivalent filter means, and the reproduction of the movie software is started. When not indicated are those formed by a control means for initially set not to perform the correction of the frequency characteristic without interposing the equivalent filter means.

According to a third aspect of the present invention, there is provided an input to which a reproduction audio signal of movie software or a reproduction audio signal of other video or audio software which is produced on the premise of being reproduced in a movie theater and which is surround-encoded is inputted. A terminal and a dedicated equivalent circuit for correcting a frequency characteristic of a reproduction audio signal of the movie software, wherein the amplitude characteristic is 2 kHz.
Attenuates linearly from 10 to high frequencies starting from z
equivalent filter means having a characteristic of -2 dB ± 1 dB at z, a surround decoder for performing surround decoding of the input reproduced audio signal, a surround decoding instruction operating means for instructing surround decoding, and the surround decoding instruction operating means When surround decoding is instructed, initialization is performed so that the input reproduced audio signal is inserted through the equivalent filter means to correct the frequency characteristics by the equivalent filter, and surround decoding is not instructed. At this time, there is provided control means for initial setting so as not to correct the frequency characteristic without interposing the equivalent filter means.

According to a fourth aspect of the present invention, there is provided an input to which a reproduced audio signal of movie software or a reproduced audio signal of other video or audio software which is produced on the premise of being reproduced in a movie theater and which is surround-encoded is inputted. A terminal and a dedicated equivalent circuit for correcting a frequency characteristic of a reproduction audio signal of the movie software, wherein the amplitude characteristic is 2 kHz.
Attenuates linearly from 10 to high frequencies starting from z
equivalent filter means having a characteristic such that z becomes -2 dB ± 1 dB, a surround decoder for surround decoding the input reproduced audio signal, and detecting whether or not the input reproduced audio signal is a signal which has been subjected to surround encoding. Surround encoding software detection means, and when an input of a surround encode signal is detected by the surround encoding software detection means, the input signal is inserted through the equivalent filter means to correct the frequency characteristics by the equivalent filter. Control means for performing initial setting and initial setting so that when the input of the surround encode signal is not detected, the input signal is not corrected for the frequency characteristic without interposing the equivalent filter means. It is.

According to a fifth aspect of the present invention, the correction of the frequency characteristic by the equivalent filter means is performed before the surround decoding process by the surround decoder.

According to a sixth aspect of the present invention, the equivalent filter means is characterized in that the amplitude characteristic is linearly attenuated toward high frequencies starting from 2 kHz and becomes −2 dB ± 1 dB at 10 kHz as a center set value. The amount of attenuation is configured to be variable by a user operation by increasing or decreasing the center set value by a predetermined amount.

[0013]

According to the experiment of the inventor, according to the invention of claim 1, as for the movie software obtained by converting a movie produced by using the X curve for television reproduction, the amplitude characteristic is 2
Attenuates linearly from high frequency to high frequency starting from 1 kHz.
The frequency characteristics were corrected by equivalent filter means having a characteristic of -2 dB ± 1 dB (± 1 dB is an allowable range of error) at 0 kHz, and reproduced under the acoustic conditions of a general home room. The characteristic that the high frequency range of which is emphasized was alleviated, and a flat characteristic in terms of audibility was obtained for most movie software. Therefore, according to the first aspect of the present invention, it is possible to listen to the soundtrack sound of movie software with an optimal frequency characteristic balance in a general home environment.

According to the second aspect of the present invention, there is provided movie software playback instruction operation means for instructing playback of movie software,
When the playback of the movie software is instructed by the movie software playback instruction operation means, the initial setting is performed so that the input reproduction audio signal is inserted through the equivalent filter means to correct the frequency characteristics by the equivalent filter. However, when the reproduction of the movie software is not instructed, the initial setting is made so as not to perform the correction of the frequency characteristic without interposing the equivalent filter means. If a movie software reproduction instruction operation means is provided, the user operates the movie software reproduction instruction operation means in accordance with whether to play the movie software or to reproduce other than the movie software, thereby giving an equivalent characteristic. Whether or not can be set arbitrarily.

According to the third aspect of the invention, when reproducing the surround-encoded movie software, the frequency characteristics are corrected by interposing the equivalent filter means in conjunction with the operation of instructing the surround decoding. So
The operation is facilitated as compared with a case where the insertion and non-insertion of the equivalent filter are separately instructed.

According to the fourth aspect of the present invention, whether or not the input signal is a surround-encoded signal is automatically detected to control the insertion and non-interposition of the equivalent filter. Switching between interposition and non-interposition can be automated.

When the correction characteristics of the equivalent filter means include abrupt changes, the phase rotation becomes large. Therefore, if surround decoding is performed after correcting the frequency characteristics, the surround decoding cannot be performed correctly. Therefore, in such a case, the frequency characteristics cannot be corrected unless the surround decoding is performed (that is, after the number of signal channels is increased), and the scale of the equivalent filter unit is increased accordingly. On the other hand, the correction characteristics used in the present invention are linearly attenuated starting at 2 kHz and set to a gentle change of -2 dB ± 1 dB at 10 kHz. Even later, the surround decoder can work properly. Therefore, as in the invention of claim 5,
Before the surround decoding (ie,
(Before the number of signal channels is increased), and the scale of the equivalent filter means can be small.

Further, even when sound design is performed using the same X-curve, depending on the characteristics of the sound stage (studio) used or the characteristics of the room to be reproduced, the above-described correction characteristics may not provide a flat characteristic in terms of audibility. Can occur. Therefore, in the invention according to claim 6, the equivalent filter means is characterized in that the amplitude characteristic is linearly attenuated toward a high frequency starting from 2 kHz and becomes −2d at 10 kHz.
Since the characteristic of B ± 1 dB is defined as the center set value, and the center set value is raised and lowered, the attenuation amount is made variable by a user operation by a predetermined amount. Regardless of this, most movie software can be reproduced at home with flat characteristics in terms of hearing.

[0019]

【Example】

(Embodiment 1) One embodiment of the present invention is shown in FIG. Room 1
0, speakers 14 of the L, C, and R channels as main speakers are located in front left, center, and right of the listening position 12, respectively.
16, 18 are provided. Further, speakers F for sound field control are provided at the front left and right and rear right and left of the listening position 12.
Speakers 20 and 2 for L, FR, RL and RR channels
2, 24, 26 are provided.

In the sound reproducing device 27, the input terminal 2
As the two-channel signals, normal two-channel stereo signals L and R or two-channel signals L _T and R _T encoded by surround encoding (for example, encoded by Dolby Pro Logic Surround (trademark) method) are input to 8 and 30. . This input signal is input to a surround decoder 34 after its frequency characteristics are corrected as necessary by the equalizers 32 and 33 constituting the equivalent filter means.
The surround decoder 34 controls the surround encode signal inputs L _T and R _T according to a command from the control means 36.
L _T, to determine the level of superiority or inferiority between the _{R T, L T + R T} , L T -R T, to determine the relative merits of each channel according to the result, each channel level controlled in accordance with the result ,
The signal is decoded into four-channel signals of main signals L, C, R and a surround signal S via a matrix circuit. For the normal two-channel stereo signal inputs L and R, the surround decoder 34 outputs the inputs L and R as they are from the L and R output terminals without performing the surround decoding process according to a command from the control means 36.

The main signals L, C, and R among the signals output from the surround decoder 34 are added and synthesized with the weighting of the main signal synthesizing means 40 in order to generate a main sound field signal. In this addition synthesis, any polarity and gain can be given to the L, C, and R channel signals as weights. That is, L, C, and R are respectively +1 and
L + C + R when added with gains of +1 and +1, and L + C when added with gains of +1, +1, -1
−R, and L + R when added with gains of +1, 0, +1 and L−R when added with gains of +1, 0, −1. This gain can be set to any value in the range of +1 to 0-1.

An example of setting the gain of each of the L, C, and R channels will be described. In the case of movie playback, three types of sound can be localized in the front. In other words, there are three types of speech of the person localized in the center, various special sound effects, and music played in the background. These front localization sounds are L,
It is included in the three channels C and R. In particular, when it is desired that the speech of a person is clearly localized at a position not to be deepened from the screen and the music and sound effects are to be spread to the depth of the screen, for example, the gain of L, C, and R is increased by +1. , 0, + 1 or +
The main signal synthesizing means 30 outputs L + R or LR by setting 1, 0, -1. In order to enjoy the atmosphere of the 70 mm screening hall, for example, the reflected sound parameter for creating the main sound field signal is localized on the front screen side (that is, in front of the listening position) as the front screen sound field, and the sound effects and music are reproduced. A reflected sound parameter that gives a relatively tight sound field extending to the back of the screen is suitable. In this case, the gains of L, C, and R are set to, for example, +1, +0.55 to +0.55.
It is desirable to set them to 0.6 and +1.

The setting of the coefficients of L, C, and R is performed based on a command from the control means 36. The setting example in the case of movie software is as described above, but a combination of various coefficient values is prepared in advance in the memory according to the sound field mode to be reproduced, and according to the listener's sound field mode selection operation, By reading any of them and setting them in the main signal synthesizing means 40, it is possible to control the sound image in various ways and to set the optimal effect, and it is possible to design a remarkably free sound effect.

The main sound field signal creating means 42 forwards the synthesized signal (synthesized main signal M) of the main signals L, C, and R in front of the listening position 12 based on the reflected sound parameter P1 read from the reflected sound parameter memory 44. It provides a relatively narrow first sound field.
The sound field control process described in Japanese Patent No. 257099 is performed. That is, the reflected sound parameter memory 44 stores
A reflected sound parameter P1 for providing a first sound field suitable for the localization directions of the main signals L, C, and R is stored. The reflected sound parameters P1 are the four sound field control speakers 20 and 2 arranged around the listening position 12 of the listener in the room 10.
In order to simulate the first sound field at 2, 24, and 26, these parameters are for generating reflected sounds to be emitted from these speakers 20, 22, 24, and 26, respectively. The reflected sound parameter P1 is configured by a combination of a delay time and a gain, and is obtained from a virtual sound source distribution or the like obtained by actual measurement or simulation in an actual sound field. FIG. 3 shows an example of the reflected sound parameters constituting one sound field. Reflected sound parameter P1
Is a parameter that forms a relatively narrow sound field in front of the listening position 12. For example, to enjoy the atmosphere of a 70 mm screening hall, the reflected sound parameter P1 is localized on the front screen side as a front screen side sound field. Thus, the reflected sound parameter that forms a relatively tight sound field in which sound effects and music spreads deep in the screen is suitable. A plurality of types of reflected sound parameters P1 are stored in the parameter memory 44 according to the type of sound field to be reproduced.
Those corresponding to the sound field mode selection operation by the listener are read out.

The convolution operation means 46 outputs the synthesized main signal M
The reflected sound parameter P1 read from the reflected sound parameter memory 44 is convoluted by digital signal processing to obtain reflected sound signals FL (front left), FR (front right),
RL (rear left) and RR (rear right) are created as the main sound field signal Mo.

On the other hand, the surround signal S is input to the surround sound field signal generating means 48 via the contact b of the switch 47. The surround sound field signal creating means 48 determines the listening position 12 for the surround signal S based on the reflected sound parameter P2 read from the reflected sound parameter memory 50.
To provide a relatively wide second sound field that wraps around
The configuration is the same as that of the main sound field signal creating means 42.
The reflected sound parameter P2 is a parameter that forms a relatively wide sound field surrounding the listening position 12, and is, for example, 70 mm.
To taste the atmosphere of the screening hall,
A reflected sound parameter that forms a vast sound field localized so as to enclose the listening position 12 is suitable. A plurality of types of reflected sound parameters P2 are also stored in the reflected sound parameter memory 50 in accordance with the type of sound field to be reproduced, and the reflected sound parameter P2 is read out according to the sound field mode selection operation by the listener.

The convolution operation means 52 outputs the surround signal S
, The reflected sound parameter P2 in each direction is convoluted by digital signal processing, and the reflected sound signals FL (front left), FR (front right), RL (rear left), and RR (rear right) in each direction are surround sound. It is created as a field signal So.

The main sound field signal Mo and the surround sound field signal So generated by the main sound field signal generating means 42 and the surround sound field signal generating means 48 are added to the adders 56, 58, 60 in the composite sound field signal generating means 54. , 62, the corresponding channels are added and synthesized, and the composite sound field signal generating means 60 outputs a composite sound field signal Co of each channel.

FL, F, and F output from the L, C, and R3 channel main signal and composite sound field signal generation means 54
The composite sound field signal Co of each of the R, RL, and RR channels is output via a D / A converter, a power amplifier, and the like (not shown), and the speakers 14, 16, and 1 of the corresponding channels are provided.
8, 20, 22, 24, and 26 and reproduced.

FIG. 4 shows an example of a sound field formed in the room 10 by the above sound field control. The conversation in the source signal
The center main speaker (center speaker) 16 is located at the center of the screen 64. The front sound effect and music are emitted from the left and right main speakers 14 and 18, and are emitted from the sound field control speakers 20, 22, 24 and 26 as the main sound field signal Mo to form the main sound field 66. I do. The main sound field 66 is a screen 64
To the depth of the image on the screen 64,
Enhance the presence.

The surround sound is a surround sound field signal So.
As a result, a surround sound field 68 which is emitted from the sound field control speakers 20, 22, 24, and 26 and has a good connection with the main sound field 66 is formed, and a sense of surrounding the listener at the listening position 12 is provided. As described above, it is possible to enjoy movie software and the like with a small number of speakers while enjoying a sufficient sound field feeling in a 70 mm screening hall or the like.

When normal two-channel stereo signals L and R are input, the operation of the surround sound field signal generating means 48 is turned off, and only the main sound field signal Mo can be generated.

The control means 36 controls ON (interpolation) and OFF (non-interpolation) of the equalizers 32 and 33 and switches 47 in accordance with the selection operation of the sound field mode by the sound field mode selection operation means 70 by the user. Switching control, on / off control of the main and surround sound field signal generating means 42 and 48, readout control of the reflected sound parameters P1 and P2 from the reflected sound parameter memories 44 and 46, and the like.

The sound field mode selection operation means 70 includes, for example, push button switches 70-1, 70-2,... As shown in FIG.
And one of the sound field modes can be selected. Here, as the sound field mode, a Hi-Fi sound field program for music reproduction without video and an AV sound field program for music reproduction with video are prepared. The Hi-Fi sound field program includes HALL (hall) and CH as sound field types to be reproduced.
URCH (church), ROCK CONCERT (rock concert venue), JAZZ CLUB (jazz club) and the like are prepared. The AV sound field program includes TV THEATER for generating a sound field suitable for programs such as TV dramas and sports broadcasts, and CONCERT VID for generating a sound field suitable for playing concert videos.
MOVIE THEATER that plays movie software (recorded on laser vision discs, video CDs, video tapes, etc.) that is EO and Dolby Pro Logic encoded in the atmosphere of a 70 mm screening hall, Dolby Pro Logic encoded movie software And a DOLBY PRO LOGIC that decodes and reproduces the data.

Of these sound field programs, HALL,
CHURCH, ROCK CONCERT, JAZZ
CLUB, TV THEATER, CONCERT V
IDEO reproduces a normal sound field mode for two-channel stereo input L and R. When these modes are selected, the equalizers 32 and 33 are turned off (the input signal is not corrected without frequency characteristic correction). Then, the surround decoder 34 outputs the L and R inputs from the L and R output terminals as they are, and the operation of the surround sound field signal creating means 48 is turned off. Then, the reflected sound parameter P1 of the selected sound field mode is read from the reflected sound parameter memory 44, a main sound field signal Mo is created, and reproduced from the sound field control speakers 20, 22, 24, and 26. . The main signals L and R are reproduced from the main speakers 14 and 18 as they are. In a normal two-channel stereo input mode in which no sound field is added (when both sound field mode selection operation means 70 are off), both the main and surround sound field signal generation means 42 and 48 are turned off.
The L and R channel signals pass through the surround decoder 34 as they are and are reproduced by the main speakers 14 and 18.

A switch 70-7 for selecting MOVIE THEATER and a switch 70-8 for selecting DOLBYPRO LOGIC constitute a movie software reproduction instruction operation means or a surround decode instruction operation means.
When these are selected, the equalizers 32 and 33 and the surround decoder 34 are turned on. As a result, the input surround encode signals L _T and R _T have their frequency characteristics corrected by the equalizers 32 and 33, and are surround-decoded by the surround decoder 34 to obtain L, C, R,
S channel signals are generated. And MOVI
When E THEATER is selected, the switch 47 is connected to the contact b side, the main and surround sound field signal generating means 42 and 48 are turned on, and the corresponding reflected sound parameters P1 and P2 are stored in the reflected sound parameter memories 44 and 46.
Is read out, the main sound field signal Mo and the surround sound field signal So are created and synthesized, and reproduced from the sound field control speakers 20, 22, 24, 26. Further, the main signals L, C, R are reproduced from the main speakers 14, 16, 18.

When DOLBY PRO LOGIC is selected, the switch 47 is connected to the contact a, and
The main and surround sound field signal generating means 42 and 48 are turned off. As a result, the main signals L, C, R are reproduced from the main speakers 14, 16, 18. The surround signal is reproduced from the sound field control speakers 24 and 26 via the adders 72 and 74.

In the above example, the modes (HALL, CHU) for reproducing the normal two-channel stereo signals L and R are used.
RCH, ROCK CONCERT, JAZZ CLU
B, TV THEATER, CONCERT VIDE
In O mode without the sound field mode and sound field) the operation of the equalizer 32 and 33 initially set to OFF (no correction), surround encoded signal L _T, mode for reproducing the R _T (MOVIE THEATER, DOLBY PR
In each sound field mode of O LOGIC), the equalizer 32,
33 on the operation of the was to be initially set to (correction present), two-channel stereo signal L, if R is prepared using a X curve, or surround encoded signal L _T, R _T is the X curve Even if it is created without using it, there are few possibilities but it is possible. Therefore, in this embodiment, as shown in FIGS. 1 and 5, an equalizer on / off switch 77 is provided, and one of the sound field modes is selected by the sound field mode selecting operation means 70, and the equalizers 32 and 33 are selected. After the initial setting of the on / off state, the on / off state can be reversed by pressing the equalizer on / off switch 77. After the reversal, it is possible to return to the initial setting state by pressing the equalizer on / off switch 77 again. Further, if any key of the post-reversal sound field mode selection operation means 70 is operated, the reversal state is released, and the initial setting states of the equalizers 32 and 33 determined for the selected sound field mode are realized. You.

Next, the equalizers 32 and 33 will be described. The equalizers 32 and 33 are composed of high-cut filters, and their amplitude characteristics are linearly attenuated toward high frequencies starting from 2 kHz, and are -2 dB ± 1 dB at 10 kHz.
(± 1 dB is an error range) is set as a standard characteristic. Further, even if sound design is performed using the same X-curve, depending on the characteristics of the sound stage used or the characteristics of the room to be reproduced, there may be cases where flat characteristics cannot be obtained in terms of audibility with the standard characteristics. In this embodiment, the correction characteristic setting value variable operation means 76 is provided so that the user can change the attenuation gradient of the characteristics of the equalizers 32 and 33.

FIG. 6 shows a specific example of the equalizers 32 and 33. The equalizers 32 and 33 are constituted by high-cut filters combining a resistor and a capacitor, and the slope of attenuation is variably set by switching the switches S1 to S4 as shown in Table 1 below.

(Table 1) 10 kHz attenuation S1 S2 S3 S40 Off Off Off Off -1 On Off Off Off -2 (Standard) On On Off Off -3 On On On Off -4 On On On On

FIG. 7 shows the amplitude characteristics of the equalizers 32 and 33 shown in FIG. According to this, the amplitude characteristics of the equalizers 32 and 33 are set to characteristics that linearly attenuate toward high frequencies starting from 2 kHz and attenuate to any of -1, -2, -3, and -4 dB at 10 kHz. Is done. -2 at 10 kHz
The characteristic that attenuates to dB is the standard characteristic. Since the phase characteristics of the equalizers 32 and 33 are as shown in FIG. 7 and the phase rotation is small, it is possible to correctly perform the surround decoding despite the fact that the frequency characteristics are corrected and then input to the surround decoder 34. it can.

The switches S1 to S4 in the equalizers 32 and 33 in FIG. 6 are switched based on the operation of the correction characteristic set value variable operation means 76, and the control means 36 in FIG.
It is realized by the instruction of. FIG. 8 shows a specific example of the correction characteristic setting value variable operation means 76. This is composed of a rotary switch 84, -1, -2, -3, -4 dB.
, And -2 dB is a standard characteristic. Another example of the correction characteristic setting value variable operation means 76 is shown in FIG. This is a push-button switch that constitutes an up operator 78 and a down operator 80.
It has two. Sound field mode selection operation means 70 (FIG. 5)
MOVIE THEATER or DOLBY P
When the RP LOGIC is selected and operated, the initial setting is -2 dB, and the display 82 displays -2 dB. From this state, pressing the up switch 78 changes the value to -1 dB, and pressing the down switch 80 changes the value to -3 dB (when pressed once) and -4 dB (when pressed twice). MO
VIE THEATER, DOLBY PRP LOG
When the mode other than the IC is selected, the setting is fixed at 0 dB, and the display 82 also displays 0 dB (however, when the equalizer is switched on by the equalizer on / off switch 77, the setting can be changed. , Indicator 82
Also displays the corresponding value. ).

In this embodiment, the MOVIE THEATER selection key 70-
7 and DOLBY PRP LOGIC selection key 70
-8 (FIG. 5) is provided with a function as a movie software reproduction instruction operation means or a surround encoding instruction operation means. As shown in FIG. 10, a key 71 for instructing the movie software is separately provided and pressed. Thus, a movie software reproduction instruction operation may be performed.

(Embodiment 2) FIG. 1 shows another embodiment of the present invention.
It is shown in FIG. This uses a Dolby AC-3 (trademark) signal as input, detects surround encoding software, and automatically controls on (interpolation) and off (non-interpolation) of the equivalent filter means. It was made. The Dolby AC-3 encoded signal is composed of a serial digital signal, which is input from an input terminal 86 and is supplied to the AC-3 terminal.
The data is decoded by the decoder 88. The signal of the Dolby AC-3 system has various modes, and each of the channels is shown in Table 2 below. The number before the mode name indicates the number of main channels, and the number after the mode name indicates the number of surround channels.

(Table 2) Mode name Channel 3/2 mode L, C, R, SL, SR 3/1 mode L, C, R, S 2/2 mode L, R, SL, SR 2/1 mode L , R, S 2/0 mode L, R

Of the above modes, the 3/1, 2/1 mode has a monaural surround channel and AC-3
The same surround signal is output from the surround output channels SL and SR of the decoder 88. Also, 2 /
In the 2, 2/1, 2/0 mode, the main output is the L and R2 channels, and no signal is output from the center output C of the AC-3 decoder 88. The 2/0 mode has no surround channel, and no signal is output from the surround output channels SL and SR of the AC-3 decoder 88. Note that these mode types are determined based on channel information included in an AC-3 signal.

Each channel L of the AC-3 decoder 88,
The output signals of C, R, SL, and SR are input to equalizers 91 to 95 constituting equivalent filter means. Each of the equalizers 91 to 95 is configured as shown in FIG. 6, for example, and its amplitude characteristic is linearly attenuated toward high frequencies starting from 2 kHz, and is -2 dB ± 1 dB (± 1) at 10 kHz.
(dB is a range of error) is set as a standard characteristic. Correction characteristic set value variable operation means 7 by user
By the switching operation of 6, the attenuation gradient can be switched as shown in FIG.

Surround encoding software detecting means 96
Detects whether the input signal is a surround-encoded signal from a channel signal included in the input signal.
That is, when the channel information indicates the 2/0 mode (Table 2), it is determined that the input is the non-surround encoding input (normal 2-channel stereo input), and the other modes (3/0 mode) are used.
(2, 3/1, 2/2, and 2/1 modes), it is determined that the input is a surround encoding input. The control means 36
Equalizers 91 to 9 for surround encoding input
5 is turned on, and the equalizer is turned off at the time of non-surround encoding input. Thereby, the equalizers 91 to 95
ON (interpolation) and OFF (non-interposition) are automated.

The present invention can be configured as an independent device as an audio amplifier, or can be configured inside a video reproducing apparatus such as a laser vision disc player, a video CD player, a video tape recorder, etc. (input terminals are devices). Corresponds to an equivalent filter means or an input portion of a surround decoder.)

[0051]

As described above, according to the first aspect of the present invention, the reproduced audio signal of the movie software is linearly attenuated from 2 kHz as a starting point toward a high frequency band.
Since the frequency characteristics are corrected by the equivalent filter means having a characteristic of -2 dB ± 1 dB (± 1 dB is an allowable range of error) at 10 kHz, the soundtrack sound of movie software is listened to with an optimum frequency characteristic balance in a general home environment. can do.

According to the second aspect of the present invention, there is provided a movie software playback instruction operation means for instructing the playback of movie software,
When the playback of the movie software is instructed by the movie software playback instruction operation means, the initial setting is performed so that the input reproduction audio signal is inserted through the equivalent filter means to correct the frequency characteristics by the equivalent filter. However, when the reproduction of the movie software is not instructed, the initial setting is made so as not to perform the correction of the frequency characteristic without interposing the equivalent filter means. If a movie software reproduction instruction operation means is provided, the user operates the movie software reproduction instruction operation means in accordance with whether to play the movie software or to reproduce other than the movie software, thereby giving an equivalent characteristic. Whether or not can be set arbitrarily.

According to the third aspect of the invention, when reproducing the surround-encoded movie software, the frequency characteristics are corrected by interposing the equivalent filter means in conjunction with the operation of instructing the surround decoding. So
The operation is facilitated as compared with a case where the insertion and non-insertion of the equivalent filter are separately instructed.

According to the fourth aspect of the present invention, whether or not the input signal is a surround-encoded signal is automatically detected to control the insertion and non-interposition of the equivalent filter. Switching between interposition and non-interposition can be automated.

The correction characteristic used in the present invention is 2k
Hz, and linearly attenuated at 10 kHz
Since the change is set to a gentle change of 2 dB ± 1 dB, the phase rotation is small and the surround decoder can operate correctly even after the characteristic correction. Therefore, the equivalent filter means can be arranged before the surround decoding (that is, before the number of signal channels increases) as in the invention of claim 5, and the size of the filter means can be small.

Further, even when sound design is performed using the same X-curve, depending on the characteristics of the sound stage (studio) used or the characteristics of the room to be reproduced, the above-described correction characteristics do not provide a flat characteristic in terms of audibility. Can occur. Therefore, in the invention according to claim 6, the equivalent filter means is characterized in that the amplitude characteristic is linearly attenuated toward a high frequency starting from 2 kHz and becomes −2d at 10 kHz.
Since the characteristic of B ± 1 dB is defined as the center set value, and the center set value is raised and lowered, the attenuation amount is made variable by a user operation by a predetermined amount. Regardless of this, most movie software can be reproduced at home with flat characteristics in terms of hearing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing a standard X curve.

FIG. 3 is a diagram illustrating an example of a reflected sound parameter P1 stored in a reflected sound parameter memory 44 of FIG. 1;

FIG. 4 is a plan view showing an example of a sound field formed in a room 10 of FIG.

FIG. 5 is a diagram showing a specific example of the sound field mode selection operation means 70 of FIG.

FIG. 6 is a circuit diagram showing a specific example of the equalizers 32 and 33 of FIG. 1;

FIG. 7 is a frequency characteristic diagram of the equalizers 32 and 33 of FIG. 1;

8 is a diagram showing a specific example of the correction characteristic setting value variable operation means 76 of FIG.

9 is a diagram showing another specific example of the correction characteristic setting value variable operation means 76 of FIG.

FIG. 10 is a diagram showing another configuration example of the movie software reproduction instruction operation means.

FIG. 11 is a block diagram showing another embodiment of the present invention.

[Explanation of symbols]

27 sound reproducing device 28, 30, 86 input terminal 32, 33, 91 to 95 equalizer (equivalent filter means) 34, 88 surround decoder 36 control means 71 movie software reproduction instruction key (movie software reproduction instruction operation means) 70-7, 70-8 sound field mode (MOVIE THE
ATER, DOLBYPRO LOGIC) selection operation means (movie software reproduction instruction operation means, surround encoding instruction operation means) 96 surround encoding software detection means

────────────────────────────────────────────────── ─── Continued on front page (51) Int.Cl. ⁶ Identification code FI H04S 1/00 H04S 7/00 Z 7/00 G10K 15/00 M

Claims (6)

(57) [Claims] An input terminal to which a reproduced audio signal of a movie software produced on the assumption that it is reproduced in a movie theater is inputted, and a frequency characteristic of the reproduced audio signal of the movie software from the input terminal is corrected. And equivalent filter means having equivalent characteristics such that the amplitude characteristic is linearly attenuated toward high frequencies starting from 2 kHz and becomes −2 dB ± 1 dB at 10 kHz. Sound reproduction device. 2. An input terminal to which a reproduction audio signal of movie software or a reproduction audio signal of other video or audio software produced on the premise of being reproduced in a movie theater is inputted, and a reproduction audio signal of the movie software. A dedicated equivalent circuit for correcting the frequency characteristics of (1), wherein the amplitude characteristics are linearly attenuated toward high frequencies starting from 2 kHz, and have characteristics such that they become −2 dB ± 1 dB at 10 kHz. Movie software playback instruction operating means for instructing playback of movie software; and when the playback of movie software is instructed by the movie software playback instruction operating means, the equivalent filter means is inserted into the input playback audio signal. Initially, the correction of the frequency characteristic by the equivalent filter is performed, and when the reproduction of the movie software is not instructed, Serial equivalent filter means without interposing an acoustic reproducing apparatus according to a control means for initially set not to perform the correction of the frequency characteristic. 3. An input terminal to which a reproduction audio signal of a movie software or a reproduction audio signal of another video or audio software which is produced on the premise of being reproduced in a movie theater and which is surround-encoded, is inputted. This is a dedicated equivalent circuit for correcting the frequency characteristic of the reproduced audio signal having a characteristic that the amplitude characteristic linearly attenuates toward a high frequency starting from 2 kHz and becomes −2 dB ± 1 dB at 10 kHz. Equivalent filter means, a surround decoder for performing surround decoding on the input reproduced audio signal, a surround decoding instruction operation means for instructing surround decoding, and the surround decoding instruction operation means when the surround decoding instruction is issued by the surround decoding instruction operation means, the input is performed. Through the equivalent filter means for the reproduced audio signal Control means for initializing so as to correct the frequency characteristic by the equivalent filter, and for not performing the correction of the frequency characteristic without inserting the equivalent filter means when surround decoding is not instructed. A sound reproducing device comprising: 4. An input terminal to which a reproduced audio signal of movie software or a reproduced audio signal of other video or audio software which is produced on the assumption that it is reproduced in a movie theater and which is surround-encoded, is inputted. This is a dedicated equivalent circuit for correcting the frequency characteristic of the reproduced audio signal having a characteristic that the amplitude characteristic linearly attenuates toward a high frequency starting from 2 kHz and becomes −2 dB ± 1 dB at 10 kHz. An equivalent filter unit, a surround decoder for surround decoding the input reproduced audio signal, a surround encoding software detecting unit for detecting whether or not the input reproduced audio signal is a signal subjected to surround encoding, and a surround encoding software detecting unit When the surround encoding signal input is detected by Initially, the input signal is inserted through the equivalent filter means to correct the frequency characteristic by the equivalent filter. When the input of the surround encode signal is not detected, the equivalent filter is applied to the input signal. A sound reproducing apparatus comprising: a control unit that performs initial setting so that the frequency characteristic is not corrected without interposing a unit. 5. The sound reproducing apparatus according to claim 3, wherein correction of frequency characteristics by said equivalent filter means is performed before surround decoding processing by said surround decoder. 6. The equivalent filter means has an amplitude characteristic of 2k.
Hz starting at 10 k
6. A characteristic in which a characteristic of -2 dB ± 1 dB at Hz is defined as a center set value, and the attenuation amount is variably changed by a predetermined amount by a user operation above and below the center set value. The sound reproducing device according to claim 1.