JP5032463B2 - Stereo sound reproduction device and stereo sound reproduction program - Google Patents

Description

  The present application belongs to the technical field of a three-dimensional sound reproducing apparatus that performs realistic sound reproduction.

  In recent years, a plurality of speakers, such as a center speaker, left and right front speakers, and left and right rear speakers, each have a role of reproduced sound, and by adding reverberation sound and changing frequency characteristics for each speaker, voice or music The surround system which amplifies the sound such as is put into practical use.

  A typical example of such a surround system includes a center speaker in front of the listener and front speakers arranged on the left and right sides thereof, a surround speaker arranged on the left and right rear or sides of the listener, and 120 Hz or less. The Dolby (registered trademark) digital 5.1ch (channel) surround system is known, which is composed of a subwoofer that only squeezes only the low frequency range of the sound. Recently, surround speakers (rear speakers), etc. A product that realizes a surround system using only front speakers or headphones without being used has also been commercialized.

In particular, as a system that realizes a surround system using headphones, the main signal and surround signal are processed using an all-pass filter that integrally adjusts only the phase of all frequency components of the sound signal to be amplified. The sound image localization is formed in the sound field to provide a realistic sound field space (for example, Patent Document 1).
JP 2002-262385 A

  However, in the above-described surround system, the surround system is realized by simple signal processing by using an all-pass filter. However, the surround system is a surround system using headphones and is premised on listening to speakers. Since it is not a system, the system expandability is poor, for example, when headphones are used by a number of listeners.

  The present application has been made in view of the above-described problems, and an example of the problem is to provide a stereophonic sound reproducing apparatus that realizes a surround system with a front speaker by simple signal processing.

In order to solve the above-mentioned problems, the invention according to claim 1 provides a sound field space with a sense of presence for a listener by enlarging a plurality of speakers based on a plurality of inputted acoustic signals. A stereophonic sound reproducing device for amplifying a right signal indicating an acoustic signal to be heard from the right direction with respect to the listener's listening position and a left signal indicating an acoustic signal to be heard from the left direction from the front of the listening position Signal processing means for performing the signal processing, and output means for outputting the signal-processed right signal and left signal from a speaker disposed in front of the listening position, and the signal processing means An all-pass filter process that integrally adjusts only the phase of all frequency components in the right signal and the left signal, and the sound image of the right signal that is amplified from the front speaker is And a delay in a plurality of frequency components to be given to each of the right signal and the left signal in order to form a sound image of the left signal amplified from the front speaker on the left side of the listener. The all-pass filter processing for converting the delay into a phase to be given to each of the right signal and the left signal by multiplying an angular frequency in each of the right signal and the left signal for each of a plurality of frequency components. the have rows for the right signal and a left signal to be loudspeakers as further said all-pass filtering, the right signal and pre-calculated phase is the all frequencies as the optimal phase corresponding to the delay to be applied to the left signal If the frequency characteristics do not monotonously decrease with increasing frequency, the frequency will increase at all frequencies. And a phase corresponding to the delay to be given to the right signal and the left signal of 500 Hz to 2 kHz, which is a frequency band that is monotonously reduced and is audibly sensitive, and 500 Hz or more after the all-pass filter processing. The configuration is the all-pass filter process that minimizes an error between the phase of the right signal and the left signal of 2 kilohertz or less .

In order to solve the above problem, the invention according to claim 5 causes a computer included in the stereophonic sound reproduction device according to any one of claims 1 to 4 to function as the signal processing means. .

In the following, preferred embodiments of the present invention will be described with reference to the drawings.

  The embodiment described below is an embodiment in which the stereophonic sound reproduction device of the present application is applied to a 5.1ch surround system (hereinafter simply referred to as a surround system).

  First, the configuration of the surround system in the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing the configuration of the surround system of the present embodiment, and FIG. 2 is an example for explaining the arrangement of speakers in the surround system of the present embodiment.

As shown in FIG. 1, the surround system 100 according to the present embodiment is installed in a listening room 10, that is, in a sound field space for providing sound to be reproduced to a listener. Also, the surround system 100 by playing a sound source such as a recording medium, or by obtaining a sound from the outside such as a television signal, a channel corresponding to the speaker (hereinafter, both "tea down channel" The sound source output device 110 that outputs an audio signal corresponding to each channel for each channel and signal processing for each of a plurality of channels output from the sound source output device 110, and only the phases of all frequency components are integrated. The signal processing apparatus 120 which performs the filter process using the all-pass filter which adjusts automatically, and the speaker system 130 which consists of various speakers corresponding to each channel are comprised.

  The surround system 100 according to the present embodiment performs predetermined signal processing on the reproduced or acquired sound and reproduces the signal by the speaker system 130 including a plurality of speakers when reproducing or acquiring the sound source. The processed sound is amplified for each speaker, and a sound field space with a sense of reality (surround feeling) can be provided to the listener.

  In particular, the surround system 100 according to the present embodiment does not have a surround speaker (hereinafter referred to as “surround speaker”) disposed on the side or rear, and does not install an audio signal (hereinafter referred to as an audio signal) to be amplified by the surround speaker. , “Surround signal”) is performed using a filter process using an all-pass filter, and the filtered surround signal is provided in front of the listening position (hereinafter referred to as “front speaker”). It is designed to make a loud voice only. The surround system 100 controls the sound image localization of the surround signal as if the surround signal was amplified from a surround speaker installed on the side or rear.

  The sound source output device 110 is composed of, for example, a media playback device such as a CD (Compact Disc) or a DVD (Digital Versatile Disc) or a reception device that receives a digital television broadcast, or by playing back a sound source such as a CD, or The broadcast sound source is acquired, and an audio signal for each channel corresponding to 5.1 ch is output to the signal processing device 120 as a digital signal.

  An audio signal for each channel output from the sound source output device 110 is input to the signal processing device 120. In addition, the signal processing device 120 adds a delay time, a reverberation time, or adjusts each frequency component to the input audio signal for each channel under the control of the system control unit 125, and all-pass. Filter processing using a filter is performed, and each audio signal subjected to the signal processing is converted into an analog signal to adjust the signal level. Then, the signal processing device 120 outputs each audio signal whose signal level is adjusted to each speaker of the speaker system 130.

  The details of the configuration and operation of the signal processing device 120 in this embodiment will be described later.

  Further, the speaker system 130 includes a center speaker 131 disposed in front of the listener, and a front speaker disposed in front of the listener and on the right side or left side of the center speaker 131 (hereinafter, the right front speaker). Is referred to as “FR speaker”, and the left front speaker is referred to as “FL speaker”. 132FR, 132FL, and a low-frequency reproduction speaker (hereinafter referred to as a speaker for low frequency reproduction) disposed in front of the listener and disposed at an arbitrary position. 134, and is arranged as shown in FIG. 2, for example.

  The channel refers to a signal transmission path of an audio signal output from the sound source output device 110, and each channel transmits an audio signal that is basically different from other channels.

  Next, while using FIG. 1 as described above, the configuration and operation of the signal processing device 120 of the present embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram for explaining the sound image control of the present embodiment, and FIG. 4 is a diagram for explaining the reason why the all-pass filter is used in the present embodiment.

  Normally, when a surround speaker is installed on the left side with respect to a listener and a predetermined sound is amplified from the surround speaker, as shown in FIG. The level of the sound that is heard by the player increases, and the sound image of the sound that is amplified from the surround speaker is formed at the place where the surround speaker is installed.

  On the other hand, as shown in FIG. 3 (b), when a predetermined sound is amplified from a speaker installed on the left front side of the listener, that is, the left front speaker, it is heard in the left ear for hearing. The sound level of the sound is slightly higher than that of the right ear, and the sound image of the sound amplified from the left front speaker is formed at the place where the left front speaker is installed.

  For this reason, as shown in FIG. 3 (c), when a surround signal is normally amplified by a front speaker, the same as in FIG. 3 (a). If the sound level generated between the two ears is adjusted for hearing, even if the sound is amplified from the front speaker, the sound image of the sound is the case where a surround speaker is installed on the left side of the listener Similarly, the surround speaker is formed at a place where it should be installed.

  Therefore, the signal processing device 120 according to the present embodiment amplifies the surround signal from the left and right front speakers, and each front speaker for each frequency component so that a sound level difference is generated between both ears at the listening position. Even when a delay time is added at the time of sound amplification, that is, a predetermined phase difference is given by the left and right front speakers, and the surround signal component is amplified or canceled at the listening position, and the sound is amplified by the front speakers. The sound image is controlled as if the sound was amplified from a surround speaker installed on the side or rear.

  In addition, the signal processing device 120 according to the present embodiment uses an all-pass filter that integrally adjusts only the phases of all frequency components when changing the phase of each frequency component with respect to the surround signal. .

  Normally, in the present embodiment, it is possible to change the phase for each predetermined frequency band using a band-pass filter. However, in the band-pass filter, as shown in FIG. 4, the frequency band to be passed (pass band) and the frequency band to be cut off (attenuation band) cannot be strictly separated, and the frequency band to be passed (pass band) and cut off. Since there is a transition region (transition region) between the frequency bands (attenuation regions) to be performed, when each frequency band whose phase is changed by the bandpass filter is added again, the amplitude in the frequency component of the transition region A level difference will occur.

  In addition, when a bandpass filter is used, it is necessary to perform a finite impulse response (FIR) type filter process, which increases the amount of calculation when performing the filter process.

  Therefore, the signal processing device 120 according to the present embodiment changes the phase of each frequency component with respect to the surround signal in order to accurately perform the filtering process and reduce the amount of calculation when the filtering process is performed. In addition, an all-pass filter that integrally adjusts only the phase of all frequency components is used.

However, in order to apply the all-pass filter, the signal processing device 120 of the present embodiment has a predetermined condition, that is,
(1) When angular frequency ω (rad / sec ) = 0 (× sampling frequency fs) , phase characteristic θ (rad) = 0,
(2) When angular frequency ω (rad / sec ) = π × sampling frequency fs , phase characteristic θ (rad) = − Nπ (N is the order of the filter),
(3) The phase characteristic θ (rad) decreases monotonously with respect to the angular frequency ω (rad / sec ).
Filter processing is performed while satisfying the above conditions.

  Specifically, as shown in FIG. 1, the signal processing device 120 of the present embodiment is used when bit stream data of a predetermined format having each channel component is input and decoded into an audio signal for each channel. An input processing unit 121 that converts the audio data into a signal format, decodes the converted audio data into audio signals for each channel, and performs signal processing for each channel, in particular, all frequency components for the surround signal. And a signal processing unit 200 that performs filter processing for integrally adjusting only the phase and performs signal processing for loudening from the front speaker.

  The signal processing device 120 includes a D / A converter 122 that performs digital / analog (hereinafter referred to as D / A) conversion on the audio signal of each channel, and a signal of the signal of each channel for each channel. A power amplifier 123 that amplifies the level, an operation unit 124 for operating each unit, and a system control unit 125 that controls each unit based on the operation of the operation unit 124 are provided.

  For example, the DSP processing unit 202 of the present embodiment constitutes the signal processing means of the present application, and the power amplifier 123 constitutes the output means of the present application.

  The input processing unit 121 receives bit stream data in a predetermined format having each channel component, and the input processing unit 121 converts the input bit stream data into audio data in a predetermined format. The converted audio data is output to the signal processing unit 200.

  For example, the input processing unit 121 converts the input bit stream data into audio data of a three-wire audio serial interface. Specifically, the input processing unit 121 converts the bit stream data into a bit clock signal and an LR clock signal. In addition, it is converted into compressed audio data and output to the signal processing unit 200.

  The signal processing unit 200 receives the audio data output from the input processing unit 121. The signal processing unit 200 decodes the input audio data into audio signals for each channel. The predetermined signal processing is performed for each channel, and the audio signal is output to each D / A converter 122 for each channel.

  Details of the configuration and operation of the signal processing unit 200 in this embodiment will be described later.

  The D / A converter 122 receives each audio signal that has been subjected to signal processing for each channel. The D / A converter 122 is a digital signal that has been input. The audio signal is converted into an analog signal and output to each power amplifier 123.

  An audio signal subjected to signal processing for each channel is input to the power amplifier 123. The power amplifier 123 controls the volume specified by the operation unit 124 under the control of the system system control unit 125. The signal level of the audio signal for each channel is amplified based on this instruction, and each amplified audio signal is output to each speaker corresponding to each channel.

  The operation unit 124 includes a remote control device including various keys such as various confirmation buttons, selection buttons, and numeric keys, or various key buttons.

  The system control unit 125 comprehensively controls general functions for performing audio reproduction by amplifying an audio signal from each speaker.

  Next, the configuration and operation of the signal processing unit 200 according to the present embodiment will be described with reference to FIGS. FIG. 5 is a block diagram illustrating a configuration of the signal processing unit 200 according to the present embodiment. FIGS. 6 and 7 are adjusted in the present embodiment in consideration of design conditions with respect to optimum phase characteristics. It is a figure for demonstrating the phase characteristic (theta) (rad) which it was. FIG. 8 is a configuration diagram showing the configuration of the filter processing unit 203 of the present embodiment.

  As shown in FIG. 5, the signal processing unit 200 of the present embodiment performs predetermined digital signal processing by operating a decoder 201 that decodes input audio data into audio signals for each channel and a user operation unit 124. A DSP processing unit 202 for performing filtering, a filter processing unit 203 for performing filtering processing on the surround signal, and a DSP-processed audio signal (hereinafter referred to as “main signal”) for amplifying the filtered surround signal from a front speaker. And an addition processing unit 205 that performs addition while adjusting the signal level.

  The decoder 201 receives input audio data such as a bit clock signal, an LR clock signal, and compressed audio data. The decoder 201 converts the input audio data into each channel. The audio signal is decoded and output to the DSP processing unit 202 for each channel.

  An audio signal decoded for each channel is input to the DSP processing unit 202, and the DSP processing unit 202 receives an instruction input from the operation unit 124 under the control of the system control unit 125. Is subjected to predetermined digital signal processing, and the signal-processed audio signal for each channel is output to the filter processing unit 203, the addition processing unit 205, or the D / A conversion unit.

  For example, when the sound field setting (hereinafter simply referred to as “sound field setting”) for a church, a stadium, a specific hall, or the like is performed by the operation unit 124, the DSP processing unit 202 enters the sound field. Thus, digital signal processing such as delay processing, frequency characteristic correction processing, and addition processing to audio signals of other channels in arbitrary audio signals is performed for each channel so that the input audio data is amplified. It has become.

  In this embodiment, since the surround signal is filtered and added to the main signal, the DSP processing unit 202 sends the surround signal to the addition processing unit 205 and the filter processing unit 203 for the main signal. Are respectively output to the addition processing unit 205.

  In addition, it is not necessary to perform filter processing on the audio signal (hereinafter referred to as “center signal”) amplified from the center speaker 131 and the audio signal (hereinafter referred to as “woofer signal”) amplified from the subwoofer 134. The DSP processing unit 202 outputs the center signal and the woofer signal directly to the D / A converter 122, respectively.

  The filter processing unit 203 is provided for each surround signal, generates a surround signal (hereinafter referred to as a “surround generation signal”) to which the delay amount of each frequency component is added for each surround signal, and adds processing unit 205. Output to.

  The addition processing unit 205 adds the surround generation signal to the main signal while adding the surround generation signal to a surround signal to which a delay amount is not added (hereinafter referred to as “surround normal signal”).

  Each surround signal is input to each filter processing unit 203 of the present embodiment. Each filter processing unit 203 considers the delay processing as a phase change when performing delay processing on each frequency component with respect to the input surround signal, and converts the optimum delay amount into a phase to perform filter processing. Is supposed to do. Then, each filter processing unit 203 uses the phase characteristics adapted to the above-described all-pass filter design conditions with respect to the optimum phase characteristics calculated by experiment, that is, all frequencies using each phase difference (phase value). A filter process for integrally adjusting only the phase of the component is executed.

Specifically, when performing filter processing, each filter processing unit 203 according to the present embodiment multiplies the delay time by the angular frequency ω (rad / second ) to convert it into a phase value, and converts each converted frequency. Filter processing for changing the phase of each frequency component is performed on the surround signal input using the phase value of the component.

Further, in the present embodiment, the filtering process is performed using the phase value adapted to the design condition of the above-described all-pass filter with respect to the optimum value calculated by the experiment. In particular, the angular frequency ω (rad / second ) is used as the design condition. ) In order to monotonously decrease the phase characteristic θ (rad), the phase characteristic calculated as optimal is adjusted so as to monotonously decrease with respect to the increase in frequency, and the filter processing unit 203 of the present embodiment Filtering is performed by using the adjusted phase characteristic (phase value).

  For example, in the present embodiment, as shown in FIGS. 6A and 6B, when the optimum phase characteristic θ (rad) is not monotonically decreased, the phase characteristic θ (rad) is monotonously decreased. In other words, the phase characteristic is adjusted so that the phase characteristic θ (rad) is monotonously decreased and the phase characteristic is as small as possible with respect to the original characteristic. The filter processing unit 203 performs filter processing by using the adjusted phase characteristic.

  When the optimum phase characteristic θ (rad) is not monotonously decreased, for example, as shown in FIGS. 7A and 7B, the phase characteristic θ is centered on 500 Hz to 2 kHz which is most sensitive to hearing. (Rad) may be adjusted. In particular, in this frequency band, as shown in FIG. 7B, even if the phase characteristic increases, the phase characteristic is adjusted so as to decrease monotonically as a whole, and the adjusted phase You may make it perform a filter process using a characteristic. Thereby, in this embodiment, sound image control can be performed more accurately.

  On the other hand, as shown in FIG. 8, each filter processing unit 203 of the present embodiment is configured using, for example, n-order cascaded second-order infinite impulse response (IIR) filters, and all frequencies A filter process for integrally adjusting only the phase of the component is executed.

In FIG. 8, (Z ⁻¹ ) indicates a delay element that is delayed by one sampling period, and A and B indicate predetermined coefficients.

  The addition processing unit 205 receives each main signal, each surround signal, and the surround signal output from each filter processing unit 203. Under the control of the system control unit 125, the surround signal is converted into the main signal. The main signal is output to each D / A converter 122.

  Specifically, the addition processing unit 205 of the present embodiment adds the filtered surround generation signals to the surround normal signals having different left and right components while adjusting the signal level and adds each surround generation signal. The generated surround normal signal is added to the main signals having different left and right components.

  For example, the addition processing unit 205 of the present embodiment applies a filter-processed right side surround signal to the left surround speaker (hereinafter referred to as “left surround signal”) to be amplified by the left surround speaker. A surround generation signal for surround speakers (hereinafter referred to as “right surround generation signal”) is added and added to a main signal (hereinafter referred to as “left main signal”) output to the FL speaker 132FL. ing. Further, the addition processing unit 205 of the present embodiment applies a filtered left surround speaker to the surround signal for the right surround speaker (hereinafter referred to as “right surround signal”) to be amplified by the right surround speaker. A surround generation signal (hereinafter referred to as “left surround generation signal”) is added to a main signal (hereinafter referred to as “right main signal”) output to the FR speaker 132FR. .

  As described above, the signal processing device 120 according to the present embodiment is a signal processing device 120 that provides a sound field space with a sense of presence to a listener by enlarging a plurality of speakers based on a plurality of input audio signals. A signal for performing signal processing for amplifying a right surround signal indicating an audio signal to be heard from the right direction with respect to a listener's listening position and a left surround signal indicating an audio signal to be heard from the left direction from the front of the listening position A processing unit 200, and a power amplifier 123 that outputs the signal-processed right surround signal and left surround signal from a speaker disposed in front of the listening position, and the signal processing unit 200 performs a right surround to be amplified. By performing filter processing that adjusts only the phase of all frequency components of the signal and left surround signal The sound processing of the right surround signal expanded from the front speaker is formed on the right side of the listener, and the signal processing for forming the sound image of the left surround signal expanded from the front speaker on the left side of the listener is performed. It has a configuration.

  With this configuration, the signal processing device 120 of this embodiment performs loudspeaking from a front speaker by performing filter processing that integrally adjusts only the phase of all frequency components of the right surround signal and the left surround signal to be loudened. The sound image of the right surround signal thus formed is formed on the right side of the listener, and the signal processing for forming the sound image of the left surround signal amplified from the front speaker on the left side of the listener is performed.

  Therefore, the signal processing device 120 according to the present embodiment can form the sound images of the left surround signal and the right surround signal at positions where the surround speakers should exist without arranging the surround speakers, Compared to delay processing (filter processing) using a bandpass filter such as Finite Impulse Response (FIR) type filter processing, the amount of computation can be reduced, and the inconsistency in amplitude level in the filter processing can be reduced. Since it does not occur, the surround system 100 can be realized by only the front speakers with simple signal processing.

  In addition, the signal processing device 120 according to the present embodiment has a configuration in which the signal processing unit 200 performs filter processing using phase characteristics having design conditions for all-pass filters.

  With this configuration, the signal processing apparatus 120 according to the present embodiment can use an all-pass filter when performing the filter process. Therefore, the signal processing apparatus 120 can perform delay processing using a band-pass filter such as a band-pass filter and a finite impulse response type filter process. In comparison, the amount of computation can be reduced and amplitude level inconsistency in filter processing is not caused.

  In the above-described embodiment, the case where the present application is applied to the surround system 100 that provides the listener with a sound field space as a surround sound field has been described (see FIG. 3). As illustrated in FIG. 9, the present application is applied to an acoustic system that provides a sound field space in which a virtual sound image is localized at a position that is spread outward as viewed from the listener rather than the actual position of the front speaker. It is also possible to do.

  In this case, parameters such as a delay amount provided for processing in the signal processing unit 200 are set to be parameters that allow sound to be heard from a preset position of the virtual sound image (see FIG. 9). Become.

  More specifically, the sound level difference between both ears generated by the processing of the signal processing unit 200 is made to coincide with the sound level difference between both ears that occurs when a speaker is placed at the position of the virtual sound image. Each parameter may be set.

  With this configuration, for example, even when a normal stereo signal (stereo signal other than the surround signal for the surround sound field) is reproduced, the corresponding sound image is localized more outward than the position of the actual front speaker, thereby further spreading. It is possible to realize stereo signal reproduction.

It is a block diagram which shows the structure in the surround system of one Embodiment which concerns on this application. It is an example for demonstrating each speaker arrangement | positioning in the surround system of one Embodiment. It is a figure for demonstrating the sound image control of one Embodiment. It is a figure for demonstrating the reason which used the all-pass filter in one Embodiment. It is a block diagram which shows the structure in the signal processing part of one Embodiment. FIG. 5 is a diagram (I) for explaining a phase characteristic θ (rad) adjusted by taking a design condition into consideration for an optimum phase characteristic in an embodiment. FIG. 6 is a diagram (II) for explaining a phase characteristic θ (rad) adjusted by taking design conditions into consideration with respect to an optimum phase characteristic in an embodiment. It is a block diagram which shows the structure of the filter process part of one Embodiment. It is a figure for demonstrating the sound image control of a deformation | transformation form.

Explanation of symbols

  100 surround system
  110 Sound source output device
  120 signal processing apparatus
  122 D / A converter
  123 Power Amplifier
  124 Operation unit
  125 System controller
  130 Speaker system
  131 Center speaker
  132 FL (front left) speaker
  133 FR (front right) speaker
  136 Subwoofer
  200 Signal processor
  201 decoder
  202 DSP processor
  203 Filter processing unit
  205 Addition processing unit

Claims (5)

A stereophonic sound reproducing apparatus that provides a sound field space with a sense of presence to a listener by enlarging a plurality of speakers based on a plurality of input acoustic signals,
Signal processing means for performing signal processing for amplifying a right signal indicating an acoustic signal to be heard from the right direction with respect to the listener's listening position and a left signal indicating an acoustic signal to be heard from the left direction from the front of the listening position When,
Output means for outputting the signal-processed right and left signals from a speaker disposed in front of the listening position;
With
The signal processing means is an all-pass filter process that integrally adjusts only the phase of all frequency components in the right signal and the left signal, and the sound image of the right signal amplified from the front speaker is heard. In order to form a sound image of the left signal amplified from the front speaker on the left side of the listener, a delay in a plurality of frequency components to be given to each of the right signal and the left signal is formed. The all-pass filter processing for converting the delay into a phase to be given to each of the right signal and the left signal by multiplying the angular frequency in each of the right signal and the left signal for each of the plurality of frequency components, There row for the right signal and a left signal to be the loudspeaker as signal processing,
Further, the all-pass filter processing is performed when the phase calculated in advance as the phase corresponding to the optimum delay to be given to the right signal and the left signal is not a frequency characteristic that monotonously decreases with respect to the increase of the frequency at all frequencies. A phase corresponding to a delay to be given to the right signal and the left signal that are monotonously decreased with respect to the increase in the frequency at all frequencies and that are a frequency band that is audibly sensitive to 500 Hz to 2 kHz. The stereophonic sound reproducing device , wherein the all-pass filter processing minimizes an error between the right signal and the left signal of 500 to 2 kilohertz after the all-pass filter processing . The stereophonic sound reproducing device according to claim 1,
The output means causes the all-pass filtered right signal and left signal to be output from the same speaker as a main signal which is a main component when forming the realistic sound field space. Sound playback device. The stereophonic sound reproducing device according to claim 1 or 2,
The three-dimensional sound reproducing apparatus, wherein the right signal and the left signal are a right surround signal and a left surround signal for making the sound field space a surround sound field space, respectively . The stereophonic sound reproducing device according to claim 1 or 2 ,
The right signal and the left signal are a right stereo signal and a left stereo signal for making the sound field space a stereo sound field other than a surround sound field, respectively. A computer program for reproducing stereophonic sound, which causes a computer included in the stereophonic sound reproducing device according to any one of claims 1 to 4 to function as the signal processing means .

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