JP4952323B2 - Audio reproduction device and audio reproduction method - Google Patents

Description

  The present invention relates to an audio reproducing apparatus and an audio processing method having two or more speakers in order to provide a surround effect.

  Due to the remarkable development of information communication technology in recent years, various functions have been installed in information communication terminals such as mobile phones, and the optimal setting change device has been developed according to the installation of these various functions. It has been done for terminals.

  In addition, it has been demanded that the speaker is placed at an optimum place according to the function installed in the mobile phone.

  For example, in order to perform high-quality stereo sound reproduction, two speakers are provided in the mobile terminal device, and the optimal speaker placement position has been devised to reduce crosstalk that occurs between the sound speakers. There is a thing (refer patent document 1: Unexamined-Japanese-Patent No. 2002-111817).

  Also, there is an image display device that has a right channel speaker unit in the right direction near the lower side of the display unit and a left channel speaker unit in the left direction, and controls the sound signal output of each speaker. (Refer to patent document 2: Unexamined-Japanese-Patent No. 2005-295382).

As shown in FIG. 14, depending on whether the image to be displayed on the display unit 10 of this apparatus is displayed vertically (FIG. 14 (a)) or horizontally (FIG. 14 (b)), The virtual output point is localized so that the acoustic effect can be obtained from the optimum position according to the display direction, and processing is performed to localize the sound image with respect to the output digital right channel signal and digital left channel signal. Is. The digital right channel signal is output to the right speaker 71, and the digital left channel signal is output to the left speaker 72.
JP 2002-111817 A JP 2005-295382 A

  As terminals are equipped with various functions, there are increasing opportunities for a plurality of people to use these functions via one terminal.

  For example, in a terminal capable of receiving terrestrial waves, the television may be viewed by a plurality of people.

  However, all of the processes that bring about the acoustic effects are assumed only when there is only one user of the mobile phone, and can be effective only for a single user.

  Therefore, for example, even if multiple people enjoy using one terminal, there is a problem that only one of the users on the front side in the display direction can enjoy the surround effect by having two speakers. It was.

  An object of the present invention is a mobile phone that can provide a surround effect that can be enjoyed by a plurality of people, which is the above-described conventional problem.

  The audio reproduction device of the present invention includes at least two or more speakers and a signal processing circuit having a plurality of filters for performing crosstalk elimination with respect to input signals to be output to the two speakers. The two speakers are disposed at diagonal positions with respect to a housing on which the speakers are mounted, and output signals after being processed by the signal processing circuit to the two speakers, respectively. An audio playback device is provided.

  Also, the audio reproduction method of the present invention provides at least two or more speakers arranged at diagonal positions with respect to the housing, and an input signal supplied to two specific speakers among the speakers. An audio reproduction method is provided that performs a process of deleting crosstalk caused by the outputs of the two specific speakers, and outputs the processed signals to the two speakers, respectively, thereby performing audio reproduction. To do.

  The audio reproduction device of the present invention is provided with a signal processing circuit for deleting crosstalk for two speakers mounted on a housing, and the two speakers are arranged at positions diagonal to the housing. Therefore, it is possible to provide the surround effect by using the two speakers not only to the user located in the display direction of the terminal but also to other users located in other directions.

  Embodiments of the present invention will be described in detail with reference to the drawings.

  First, the configuration of an information communication terminal 1 (hereinafter referred to as a terminal) according to an embodiment of the present invention having two speakers will be described with reference to FIGS.

  FIG. 1 is a perspective view of a terminal 1 according to an embodiment of the present invention.

  The terminal 1 according to the embodiment of the present invention has a lower right side across the display unit 10 in the first housing 16 having the display unit 10 so that a sound effect can be provided to a plurality of listeners. A right speaker (hereinafter referred to as a lower right speaker 74) and a left speaker (hereinafter referred to as an upper left speaker 75) are arranged so as to be diagonal at the upper left position. According to this position, as described in Patent Document 2, the user may set the display direction of the display unit 10 of the terminal 1 to be a vertically long main display mode, as shown in Patent Document 2, or display direction. May be horizontally long. Even when the display direction is changed to landscape, the user can enjoy the surround effect due to the distant speaker positions.

  As shown in FIG. 1, in the terminal 1 according to the embodiment of the present invention, the first casing 16 having the display unit 10 and the second casing 17 are foldably coupled via a hinge (not shown). Although a folding type terminal is illustrated, any type of terminal such as a straight type or a biaxial rotating hinge type may be used.

  FIG. 2 is a block diagram illustrating a configuration of the terminal 1 according to the embodiment of this invention.

  In FIG. 2, the terminal 1 controls communication between the CPU 12 (Central Processing Unit) and the network of the terminal 1, authentication, execution of software on the terminal, control, control of the display unit 10, and control from the operation unit 14. Stores a control unit 11 including a memory (ROM: Read Only Memory) 13 that stores a computer program that instructs the operation of the terminal 1 such as input control, and phone book data, mail data, and the like that the terminal 1 uses during normal operation. And a random access memory (RAM) 15.

  The wireless communication unit 3 has a function of performing wireless communication with a mobile communication network (not shown) via the antenna 4, modulates a transmission signal, sends it to the mobile communication network as a wireless signal, The radio signal is demodulated and sent to the control unit 11 as a digital signal.

  Further, the terminal 1 receives user input from a receiver 6 that outputs a voice such as a call voice, a microphone 5 that receives a user's voice, a keypad, and the like to perform a voice call. An operation unit 14 that converts key input into a signal and sends it to the control unit 11, a display unit 10 that can display various information such as received mail information and images, a ring tone for a user (listener), It includes a lower right speaker 74 and an upper left speaker 75 which are reproduction means for reproducing music.

  The voice processing unit 2 converts voice input from the microphone 5 into voice data and outputs the voice data to the wireless communication unit 3, and converts voice data received from the wireless communication unit 3 into voice and outputs the voice to the receiver 6. . Further, at the time of ringtone or music playback, the audio processing unit 2 outputs the right signal and the left signal output from the signal processing circuit 21 to the left and right speakers (here, the lower right speaker 74 and the upper left speaker 75), respectively.

  In this way, sound signals output from both speakers reach the ears of the listener 27. If there are two left and right speakers here, an event called crosstalk occurs.

  This means that sound signals radiated from the lower right speaker 74 and the upper left speaker 75 can be heard by the other ear other than the ear to be transmitted.

  For this reason, in general, when two speakers are provided, a filter design for canceling crosstalk for preventing the listener 27 from listening to excessive sounds is performed in order to enhance the surround effect.

  The audio processing unit 2 includes a signal processing circuit 21 that also performs crosstalk cancellation processing on signals output to these speakers.

The signal processing circuit 21 processes signals output to both speakers by performing filter processing.
[General crosstalk cancellation processing]
FIG. 3 is a perspective view showing a comparison terminal 1 ′ (hereinafter simply referred to as a terminal 1 ′) for comparison with the terminal 1 according to the embodiment of the present invention.

  First, in order to explain the crosstalk cancellation by the signal processing circuit 21, when a general speaker arrangement is performed, that is, as shown in FIG. As an example of the case where the right speaker 71 and the left speaker 72 are arranged, a description will be given using the terminal 1 ′.

  Here, since the terminal 1 ′ differs from the terminal 1 of the embodiment of the present invention only in the signal processing circuit 21 ′ and the configuration of the filter included in this circuit, the other components are common. A number shall be used. Further, the terminal 1 ′ has a right speaker at the same height with respect to the longitudinal direction of the housing on the left and right sides of the display unit 10, or on the side wall surface with respect to the surface on which the display unit 10 is arranged. 71 and a left speaker 72 are provided.

  FIG. 4 is an image diagram showing a relationship between two speakers of the terminal 1 ′, a signal processing circuit 21 ′ that performs signal processing for crosstalk deletion, and a listener 27.

  Here, it is assumed that the listener 27 exists on the left and right centers of both speakers of the terminal 1 ′.

  The crosstalk cancellation of the left and right speakers 71 and 72 is performed by the signal processing circuit 21 ′ included in the audio processing unit 2.

  The signal processing circuit 21 ′ performs a filtering process on the right signal a for the right speaker and the left signal b for the left speaker, which are input signals generated by the sound processing unit 2, and then outputs them to the respective speakers. To do.

  Further, as shown in the figure, the signal processing circuit 21 ′ includes a first filter 81 that outputs a branch signal from the left signal b for the left speaker to the right speaker 71, and a branch signal from the right signal a for the right speaker. Is output to the left speaker 72 and performs respective signal processing.

  These filters are equivalent circuits for canceling the crosstalk that occurs between the left and right speakers. In FIG. 4, F1 is shown as the transfer characteristic of the first filter 81, and F2 is shown as the transfer characteristic of the second filter 82. .

  In addition, both the first filter 81 and the second filter 82 also perform phase shift processing of the input branch signal in order to cancel crosstalk generated in the left and right speakers.

  Based on the control by the control unit 11, the signal processing circuit 21 ′ outputs the signal that has passed through the first filter 81 to the right speaker 71 via the right subtractor 91. Similarly, the signal processing circuit 21 ′ outputs the signal that has passed through the second filter 82 to the left speaker 72 via the right subtractor 92.

  Thereby, the right speaker 71 outputs a sound signal a after subtracting a signal obtained by processing a part of the left signal b by the first filter 81 from the right signal a, and similarly, the left speaker 72 receives the signal from the left signal b. The sound signal b after subtracting the signal obtained by processing a part of the right signal a by the second filter 82 is output.

  With this filter, the control unit 11 can remove only the sound component that causes crosstalk reaching the ear of the listener 27.

  That is, the signal processing circuit 21 ′ performs inversion processing with a filter on the sound component that becomes crosstalk, and outputs the processed sound signal to the right speaker 71 and the left speaker 72.

  As a result, the sound signal that is the component of the sound that causes crosstalk cancels the sound signal that has been subjected to the inversion process, and does not reach the ear of the listener 27.

  The listening sound that has been subjected to the crosstalk cancellation processing by the signal processing circuit 21 'will be described below.

  Here, the transmission characteristic from the right speaker 71 to the right ear of the listener 27 is [A], the transmission characteristic to the left ear is [A] ′, and similarly, the transmission from the left speaker 72 to the left ear of the listener 27 is transmitted. The characteristic is [B], and the transfer characteristic up to the right ear is [B] ′.

  Further, the sound signal a output from the right speaker 71 shown in FIG. 4 includes the received sound including the sound transmission characteristic [A] between the right speaker 71 and the right ear [SR], and similarly from the left speaker 72. The received sound including the transfer characteristic [B] between the left speaker 72 and the left ear in the output sound signal b is assumed to be [SL].

  [SR] and [SL] are the right signal a, the left signal b, the transfer characteristics [A] and [B], F1 indicating the transfer characteristic of the first filter 81, and F2 indicating the transfer characteristic of the second filter 82. Can be used as follows.

[SR] = [A]. (Ab-F1) --- ((1) -R)
[SL] = [B]. (Ba-F2) --- ((1) -L)
Similarly, in the sound signal b output from the left speaker 72, the received sound including the transfer characteristic [B] ′ between the left speaker 72 and the right ear is [SL] ′, and the sound output from the right speaker 71. If the received sound including the transfer characteristic [A] ′ between the right speaker 71 and the left ear is [SR] ′ in the signal a, the received sound that becomes crosstalk can be expressed as follows.

[SR] ′ = [A] ′ · (ab · F1) --- ((2) -R)
[SL] '= [B]'. (Ba-F2) --- ((2) -L)
Since all sounds received by the right ear (hereinafter referred to as [HR]) include crosstalk sounds, assuming that the values of the transfer characteristics [A] and [B] are 1, respectively, the equations (1) and (1) From 2)
[HR] = [SR] + [SL] '--- ((3) -R)
= [A] · (ab−F1) + [B] ′ · (ba−F2)
= A ([A] −F2 · [B] ′) + b ([B] ′ − [A] · F1) −−− ((4) −R)
All sounds (hereinafter referred to as [HL]) received by the left ear are
[HL] = [SL] + [SR] '--- ((3) -L)
= [B] · (b−a · F2) + [A] ′ · (ab−F1)
= A ([A] ′ − F2 · [B]) + b ([B] −F1 · [A] ′) −−− ((4) −L)
Here, regarding the transfer characteristic from the left speaker 72 to the right ear of the listener 27, if [B] ′ = [A] · F1 holds, the equation ((5) −R) is
[HR] = a ([A] −F2 · [B] ′) (∵ [B] ′ = [A] · F1) --- ((5) -R)
Similarly, regarding the transfer characteristic from the right speaker 71 to the left ear of the listener 27, if [A] ′ = [B] · F2 holds, the equation ((5) −L) is
[HL] = b ([B] −F1 · [A] ′) (∵ [A] ′ − F2 · [B] −−− ((5) −L)
Can be shown. Thereby, only the sound signal a output from the right speaker 71 remains in the right ear, and only the sound signal b output from the left speaker 72 remains in the left ear.

  In this way, by calculating and designing the filter value, when the sound signal a from the right speaker 71 is heard only with the right ear and the sound signal b of the left speaker 72 is heard only with the left ear, the listener 27 It is possible to experience the spread of sound, which is a surround effect.

[Crosstalk cancellation processing according to the embodiment of the present invention]
Next, the filter design that provides the surround function of the embodiment of the present invention will be described.

  First, a listener who is in a normal viewing position with respect to the terminal 1 (hereinafter, referred to as a vertical listener 28) and a listener who is in a viewing position right next to the vertical listener 28 (hereinafter, a right lateral listener). 29) will be described.

  FIG. 5 shows the first housing 16 of the terminal 1 according to the embodiment of the present invention, the standing positions of the vertical listener 28 and the right horizontal listener 29, and the transmission characteristics to the left and right ears of each listener. It is the image figure shown with the bird's-eye view.

  As shown in FIG. 5, viewing on the display unit 10 that is vertically long from the standing position of the vertical listener 28 is viewed vertically on the display unit 10 that is horizontally long from the standing position of the right horizontal listener 29. Is viewed horizontally.

Further, the standing position of the vertical listener 28 is assumed to be on the left and right centers of both the left and right speakers, similarly to the standing position of the listener of the terminal 1 ′ described above. Thereby, the listening sound [HR (v)] in the right ear of the vertical listener 28 and the [HL (v)] listening sound in the left ear are the listening sounds [HR] and [HL] of the listener of the terminal 1 ′ described above. ],
[HR (v)] = [HR] = [SR] + [SL] '--- ((4) -R)
[HL (v)] = [HL] = [SR] '+ [SL] --- ((4) -L)
Can be shown.

  The listening sound of the right lateral listener 29 that exists at the same equidistant distance from the terminal 1 to the vertical listener 28 and that is at the center of the right and left of the lower right speaker 74 and the upper left speaker 75 will be described with reference to FIG.

  First, in FIG. 5, since the distance from the terminal 1 to the right lateral listener 29 and the distance to the vertical listener 28 are the same distance, both listeners are located at the center of both speakers. However, the right horizontal listener 29 exists at a position symmetrical to the position of the vertical listener 28 around the line (u-u ′) connecting the upper left speaker 75 and the lower right speaker 74 as an axis.

  Therefore, the distance from the lower right speaker 74 to the right ear of the vertical listener 28 and the left ear of the right horizontal listener 29 are equal, and therefore, the sound transmission characteristics between them are indicated by [A]. Is possible.

  Similarly, the distance from the upper left speaker 75 to the left ear of the vertical listener 28 and the right ear of the right lateral listener 29 are equal, and the transfer characteristic between them can be indicated by [B].

  Further, the transfer characteristic from the lower right speaker 74 to the right ear of the right side listener 29 is indicated by [A] ′, and the transfer characteristic from the upper left speaker 75 to the left ear of the right side listener 29 is indicated by [B] ′. it can.

Thereby, the listening sound [HR (Rh)] in the right ear of the right lateral listener 29 is transmitted from the lower right speaker 74 to the left ear to the sound signal a output from the lower right speaker 74 shown in FIG. Listening sound [SL] including the transmission characteristic [B] between the upper left speaker 75 and the right ear in the listening sound [SR] ′ including the characteristic [A] ′ and the sound signal b output from the upper left speaker 75 Will be added.
[HR (Rh)] = [SL] + [SR] '--- ((6) -R)
Similarly, the listening sound [HL (Rh)] in the left ear of the right lateral listener 29 is transmitted from the upper left speaker 75 to the right ear of the right lateral listener 29 to the sound signal b output from the upper left speaker 75. Transfer characteristics between the left ear of the right lateral listener 29 from the lower right speaker 74 to the sound signal a output from the lower right speaker 74 and [SL] ′ including the characteristic [B] ′ [SR] which is a listening sound including A].
[HL (Rh)] = [SR] + [SL] '--- ((6) -L)
At this time, with respect to the signal processing performed in the signal processing circuit in the terminal 1 of the embodiment of the present invention and the listening state of the vertical listener 28 and the right horizontal listener 29, the filter processing for the right signal a and the right signal b, The sound signal a and sound signal b output from the speaker will be described with reference to FIG.

  FIG. 6 is an image diagram showing the relationship between the two speakers of the terminal 1, the signal processing circuit 21 that performs signal processing for crosstalk deletion, and the longitudinal listener 28.

  In the signal processing circuit 21 of the terminal 1 according to the embodiment of the present invention, a third filter 85 is further added to the signal processing circuit 21 ′ in the terminal 1 ′ shown in FIG. The difference is that it is provided until the left signal b is input to the upper left speaker 75.

  Also, as shown in FIG. 5, each speaker is arranged diagonally with respect to the first housing 16, and the distance from each speaker to the listener is different, so the lower right speaker shown in FIG. 74 and the upper left speaker 75 are not shown in parallel.

  The listening sounds [SR] and [SL] shown in FIG. 6 are the right signal a, the left signal b, F1 indicating the transfer characteristic of the first filter 83, F2 indicating the transfer characteristic of the second filter 84, and the third filter 85. By using F3 indicating the transfer characteristic of the above and the above-described transfer characteristic, it can be expressed as follows.

[SR] = [A] (ab · F1) --- ((7) -R)
[SL] = [B] (b.F3-a.F2) --- ((7) -L)
The sound signal a output from the lower right speaker 74 shown in FIG. 6 actually reaches the left ear of the longitudinal listener 28 and the received sound including its transfer characteristic is [SR] ′, and similarly, the upper left speaker 75 The received sound including the signal where the output sound signal b reaches the right ear and its transfer characteristic is denoted as [SL] ′.

  Accordingly, the listening sounds [SR] ′ and [SL] ′ illustrated in FIG. 6 can be expressed as follows using the right signal a, the left signal b, and the above-described transfer characteristics.

[SR] ′ = [A] ′ (ab · F1) --- ((8) -R)
[SL] ′ = [B] ′ (b · F3-a · F2) --- ((8) -L)
The listening sounds [HR (v)] and [HL (v)] of the longitudinal listener 28 are expressed by the following equations (4), (7), and (8):
[HR (v)] = [SR] + [SL] ′
= [A] (ab-F1) + [B] '(b-F3-a-F2)
= [A] -a- [A] -b-F1 + [B] '-b-F3- [B]'-a-F2
= A ([A]-[B] '. F2) + b ([B]'. F3- [A] .F1) --- ((9) -R)
[HL (v)] = [SR] ′ + [SL]
= [A] '(ab-F1) + [B] (b-F3-a-F2)
= [A] '. A- [A]'. B.F1 + [B] .b.F3- [B] .a.F2
= A ([A] '-[B] .F2) + b ([B] .F3- [A]'. F1) --- ((9) -L)
Can be shown.

  Here, if [B] ′ · F3 = [A] · F1, the value of Expression (9) -R is as follows.

[HR (v)] = a ([A]-[B] ′ · F2) (∵ [B] ′ · F3 = [A] · F1)
--- ((10) -R)
Similarly, if [A] ′ = [B] · F2, the value of Expression (9) -L is as follows.

[HL (v)] = b ([B] · F3- [A] ′ · F1) (∵ [A] ′ = [B] · F2)
--- ((10) -L)
Thus, the values of the first filter 83 (F1), the second filter 84 (F2), and the third filter 85 (F3) are transferred to the transfer functions [A], [A] ′, [B], [B ] 'Is designed so as to satisfy the expressions ((10) -R) and ((10) -L).

  Thereby, only the right signal a can be heard by the right ear of the vertical listener 28 and only the left signal b can be heard by the left ear, and the terminal 1 can provide the surround effect.

  In addition, how to hear the right side listener 29 at this time will be described.

The listening sound of the right side listener 29 is shown in FIG.
[HR (Rh)] = [SR] ′ + [SL] −−− ((6) −R)
[HL (Rh)] = [SR] + [SL] '--- ((6) -L)
Indicated by

  The signal processing performed in the signal processing circuit at this time will be described.

  The listening sounds [HR (Rh)] and [HL (Rh)] of the right lateral listener 29 are [SR], [SL], [SR] ′, and [SL] shown by the equations (7) and (8). Using ′, the following equation can be derived from equation (6).

[HR (Rh)] = [SR] ′ + [SL] (= [HL (v)])
= [A] '(ab-F1) + [B] (b-F3-a-F2)
= [A] '. A- [A]'. B.F1 + [B] .b.F3- [B] .a.F2
= A ([A] '-[B] .F2) + b ([B] .F3- [A]'. F1) --- ((11) -R)
[HL (Rh)] = [SR] + [SL] ′ (= [HR (v)])
= [A] (ab-F1) + [B] '(b-F3-a-F2)
= A ([A]-[B] '. F2) + b ([B]'. F3- [A] .F1) --- ((11) -L)
“[A] ′ = [B] · F2”, which is the condition shown in the equation (10), is changed to the equation ((11) −R), and “[B] ′ · F3 = [A] · F1” is changed to the equation ( Substituting for (11) -L),
[HR (Rh)] = b ([B] · F3- [A] ′ · F1) --- ((11) -R)
[HL (Rh)] = a ([A]-[B] ′ · F2) --- ((11) -L)
It becomes.

  From this equation (11), it is shown that the right lateral listener 29 receives only the left signal b with the right ear and only the right signal a with the left ear.

  Therefore, the right side listener 29 can also listen to the sound with the crosstalk canceled.

Also, under the condition that [A] ′ = [B] · F2 and [B] ′ · F3 = [A] · F1 are satisfied,
From Equation (10) and Equation (11),
([HR (Rh)] = [HL (v)])
([HL (Rh)] = [HR (v)])
Is established.

  That is, as compared with the vertical listener 28, the right horizontal listener 29 is such that the sound signal a of the lower right speaker 74 reaches the left ear and the sound signal b of the upper left speaker 75 reaches the right ear. And you will hear a sound that is reversed left and right.

  However, the listener can enjoy the three-dimensional surround effect only by performing the crosstalk cancellation processing of the sound from both speakers, and in this regard, the surround effect of the embodiment of the present invention. It is possible to provide an audio playback device and an audio playback device that provide the above.

  Next, how to determine the value of the third filter 85 (F3) will be described in order not only to listen to the crosstalk canceled sound but also to listen to an equivalent sound in the left and right ears.

  For the sake of simplicity, it is assumed that there is no first filter 83 and second filter 84, which are equivalent circuits for crosstalk cancellation performed in the signal processing circuit 21 shown in FIG.

  Here, based on this assumption, using the equations ((9) -R) and ((9) -L) and considering the signal sound reaching the left and right ears of the longitudinal listener 28, the following equations It becomes possible to show by.

[HR (v)] = a [A] + b [B] ′ · F3 −−− ((9) ′ − R)
[HL (v)] = a [A] ′ + b [B] · F3 −−− ((9) ′ − L)
Next, the listening sounds [HR] and [HL] when using the terminal 1 ′ shown in FIG. 3 in which the distance between the left and right ears of the listener 27 and the left and right speakers is equal, respectively, (4) -R) and formula ((4) -L).

That is,
[HR] = a ([A] −F2 · [B] ′) + b ([B] ′ − [A] · F1) −−− ((4) −R)
[HL] = a ([A] ′ − F2 · [B]) + b ([B] −F1 · [A] ′) −−− ((4) −L)
Here, as in the equations ((9) ′-R) and ((9) ′-L), this is an equivalent circuit for crosstalk cancellation performed in the signal processing circuit 21 ′ shown in FIG. Considering the listening sound when it is assumed that the first filter 83 and the second filter 84 are not present, they can be expressed by the following equations.

[HR] = a [A] + b [B] ′
[HL] = a [A] ′ + b [B]
Here, since the distances to the left and right speakers are equal to each other, when [A] = [B] and [A] ′ = [B] ′ are substituted, the equations ((4) −R), ((4) -L) can be expressed by the following formula ((4) ′-R) and formula ((4) ′-L).
[HR] = a [A] + b [B] ′
= A [A] + b [A] '--- ((4)'-R)
[HL] = a [A] ′ + b [B]
= A [A] '+ b [A] --- ((4)'-L)
The expressions ((4) ′-R) and ((4) ′-L) are terminals 1 ′ in which the distance between the left and right ears of the listener 27 and the left and right speakers is equal, and the first filter 81 (F1), The listening sound that reaches the left and right ears when the second filter 82 (F2) is not used is shown.

  Here, when compared with the above-mentioned formulas ((9) ′-R) and formulas ((9) ′-L), [B] ′ · F3 = [A] ′ and [B] · F3 = [A]. Sometimes, the listening sounds [HR (v)] and [HL (v)] of the longitudinal listener 28 on the terminal 1 are equal to the listening sounds [HR] and [HL] of the listener 27 on the terminal 1 '.

  That is, when F3 satisfies the following expression, the listening sound in the left and right ears in the terminal 1 is a condition for listening as the listening sound when the left and right ears and the left and right speakers are equidistant.

F3 = ([A] ′ / [B] ′)
= ([A] / [B])
As a result, the terminal 1 can provide a surround effect by performing crosstalk cancellation, and can provide an equivalent listening sound from the left and right speakers to the left and right ears of the listener.

Note that the right side listener 29 is shown in FIG. 5 only when it exists on the right side of the terminal 1. This is because the right lateral listener 29 existing on the left cannot enjoy the surround effect by the crosstalk cancellation according to the embodiment of the present invention.
[Second Embodiment]
Next, the information communication terminal 100 (hereinafter referred to as the terminal 100) that performs crosstalk cancellation according to the second embodiment of this invention will be described.

  FIG. 7 is a perspective view of the terminal 100 according to the second embodiment.

  The difference from FIG. 1 showing the terminal 1 of the first embodiment is that the positions of the speakers are different, that is, the lower left speaker 76 instead of the lower right speaker 74 and the upper right speaker 73 instead of the upper left speaker 75. It is a point that has been.

  FIG. 8 is a block diagram illustrating a configuration of the terminal 100 according to the second embodiment. The audio processing unit 2 outputs the signals processed by the signal processing circuit 21 to the upper right speaker 73 instead of the lower right speaker 74 and to the lower left speaker 76 instead of the upper left speaker 75, respectively.

  As described above, since the terminal 100 of the second embodiment is different only in the position of the speaker, the other components are the same as those in FIG. 1, which is a block diagram showing the configuration of the first embodiment. Numbers are used.

  FIG. 9 is an image diagram illustrating a relationship with a listener in the terminal 100 (only the first housing 160 is illustrated) according to the second embodiment.

  As shown in FIG. 9, the terminal 100 according to the second embodiment is in a so-called point target position in which the positions of the left and right speakers are upside down with respect to the terminal 1 according to the first embodiment. is there.

  For this reason, the horizontal listener 30 (hereinafter referred to as the left horizontal listener) in the terminal 100 will be described as being located on the left side when viewed from the vertical listener 28.

  Here, the vertical listener 28 and the left horizontal listener 30 are in the center of the left and right of the terminal 100, and the distance from the vertical listener 28 to the terminal 100 and the distance between the left horizontal listener 30 and the terminal 100 are equal. And

  In order to simplify the description to be described later, the distance between the vertical listener 28 and the terminal 100 is the same as the distance from the terminal 1 to the listener 27 in the first embodiment shown in FIG. To do.

  That is, the positional relationship among the terminal 100, the vertical listener 28, and the left horizontal listener 30 in FIG. 9, and the terminal 1, the vertical listener 28, and the right horizontal receiver in FIG. 5 shown as the terminal 1 of the first embodiment. The positional relationship with the listener 29 is in a line-symmetrical position with the left and right center of the terminal 100 as an axis.

  Therefore, similarly to the first embodiment, the transfer characteristic from the upper right speaker 73 to the right ear of the vertical listener 28 is [B], and the transfer characteristic to the left ear of the vertical listener 28 is [B] ′, The transfer characteristic from the lower left speaker 76 to the left ear of the longitudinal listener 28 can be indicated by [A], and the transfer characteristic to the right ear can be indicated by [A] ′.

  Similarly, the transmission characteristic from the lower left speaker 76 to the right ear of the left lateral listener 30 is [A], the transmission characteristic to the left ear is [A] ′, and the upper right speaker 73 to the left ear of the left lateral listener 30. It is also possible to indicate the transfer characteristic of [B] and the transfer characteristic up to the right ear by [B] ′.

  The configuration and processing contents of the signal processing circuit 21 included in the terminal 100 according to the second embodiment are the same as those of the terminal 1 according to the first embodiment.

  That is, the signal output to the lower right speaker 74 in the terminal 1 of the first embodiment is output to the lower left speaker 76 in the terminal 100 of the second embodiment, and similarly the first embodiment. It is assumed that the signal output to the upper left speaker 75 in the terminal 1 of the embodiment is output to the upper right speaker 73 in the terminal 100 of the second embodiment.

  In this case, the listening sounds [HR (v)] and [HL (v)] that reach the ears of the longitudinal listener 28 are the same as the listening sounds that reach the left and right ears of the longitudinal listener 28 of the first embodiment. Since it becomes reverse, it becomes possible to show with the following formula | equation from Formula ((9) -R) and Formula ((9) -L).

[HR (v)] = [SR] ′ + [SL]
= A ([A] '-[B] .F2) + b ([B] .F3- [A]'. F1) --- ((9) -R)
[HL (v)] = [SR] + [SL] ′
= A ([A]-[B] '. F2) + b ([B]'. F3- [A] .F1) --- ((9) -L)
Also, the left lateral listener 30 hears a listening sound that is opposite to the left and right listening sounds in the left and right ears of the right lateral listener 29 in the first embodiment.

  For this reason, the listening sounds [HR (Lh)] and [HL (Lh)] reaching the left and right ears of the left lateral listener are equations ([(Lh)] and [HR (Rh)], respectively, (( 11) -L) and the formula ((11) -R) can be used to represent the formula ((12) -R) and the formula ((12) -L).

[HR (Lh)] = [SR] + [SL] ′
= [A] (ab-F1) + [B] '(b-F3-a-F2)
= A ([A]-[B] '. F2) + b ([B]'. F3- [A] .F1) --- ((12) -R)
[HL (Lh)] = [SR] ′ + [SL]
= [A] '(ab-F1) + [B] (b-F3-a-F2)
= A ([A] '-[B] .F2) + b ([B] .F3- [A]'. F1) --- ((12) -L)
Here, if [B] ′ · F3 = [A] · F1 and [A] ′ = [B] · F2, the values of Equation (9) -R and Equation (9) -L are as follows: It becomes.

[HR (v)] = b ([B] · F3- [A] ′ · F1) (∵ [A] ′ = [B] · F2)
--- ((13) -R)
[HL (v)] = a ([A] − [B] ′ · F2) (∵ [B] ′ · F3 = [A] · F1)
--- ((13) -L)
Thus, the vertical listener 28 in the second embodiment is opposite to the left and right listening sound for the vertical listener in the first embodiment.

  That is, the longitudinal listener 28 in the second embodiment can listen to the left signal b with the right ear and listen to the right signal a with the left ear, and as a result, the expression ((13) -R) As shown in the equation (13) -L), it is possible to hear the received sound whose crosstalk has been canceled.

Next, the above-mentioned formulas ((12) -R) and formulas ((12) -L) indicating the listening sounds [HR (Lh)] and [HL (Lh)] of the left lateral listener 30 are [B]. Under the condition of '· F3 = [A] · F1, [A]' = [B] · F2,
[HR (Lh)] = a ([A] '-[B] .F2) --- ((12) -R)
[HL (Lh)] = b ([B] ′ · F3- [A] · F1) --- ((12) -L)
It can be shown by the expression.

  This indicates that the left lateral listener 30 listens to the right signal a with the right ear and listens to the left signal b with the left ear.

Furthermore, under this condition,
([HR (Lh)] = [HL (v)])
([HL (Lh)] = [HR (v)])
Is established.

  This is because the left side listener 30 in the left side position instead of the right side listener 29 also receives a sound that is opposite to that of the vertical listener 28, but in the second embodiment, This also shows that the terminal 100 can receive a sound with the crosstalk canceled.

  Therefore, by using the terminal 100 according to the second embodiment of the present invention, the left lateral listener 30 located on the left side of the terminal 100 can also listen to the crosstalk-cancelled sound.

  In this way, any listener can listen to the crosstalk-cancelled sound from both speakers, and can enjoy a three-dimensional surround effect.

  It is possible to provide an audio reproduction device and an audio reproduction method that provide the surround effect of the second embodiment of the present invention for the vertical listener 28 and the left horizontal listener 30.

  As in the embodiment of the present invention, in the second embodiment, only the left listener 30 can listen to the crosstalk-cancelled sound, and the right listener 29 located on the right side is The surround effect by the crosstalk cancellation of the second embodiment of the present invention cannot be enjoyed.

[Third Embodiment]
Next, the terminal 101 according to the third embodiment of this invention will be described.

  FIG. 11 is a perspective view illustrating a terminal 101 according to the third embodiment.

  As shown in FIG. 11, the casing 161 of the terminal 101 has four speakers, which are an upper right speaker 73, a lower right speaker 74, an upper left speaker 75, and a lower left speaker 76, respectively.

  FIG. 12 is a block diagram illustrating a configuration of the terminal according to the third embodiment.

  The sound processing unit 20 outputs the signal processed by the signal processing circuit 21 to these speakers under the control of the control unit 11.

  Since the components other than the speaker and the audio processing unit 20 of the terminal 101 are the same as those of the first embodiment shown in FIG. 2, the description will be given using the same numbers in FIG.

  Here, when the terminal 101 of the third embodiment outputs sound from the speaker, the first output form that outputs using the lower right speaker 74 and the upper left speaker 75, and the upper right speaker 73, One of the second output forms to be output using two of the lower left speakers 76 is selected and output.

  The speakers (upper right speaker 73, lower right speaker 74, upper left speaker 75, lower left speaker 76) can be freely switched by a switching circuit (not shown) included in the audio processing unit 20 based on an instruction from the control unit 11.

  This switching also enables switching between the first output form and the second output form.

  In the first output mode, the control unit 11 performs the same speaker control as that of the terminal 1 of the first embodiment, and in the second output mode, the control unit 11 is connected to the terminal 100 of the second embodiment. The same speaker control is performed.

  Based on the control of the control unit 11, which speaker is connected to the signal processed by the signal processing circuit 21 according to which output form is used is switched by a switching circuit (not shown) of the audio processing unit 20.

  That is, in the case of the first output form, the signal processed by the signal processing circuit 21 and output through the right subtractor 93 is output to the lower right speaker 74, and the signal output through the left subtractor 94 is Output to the upper left speaker 75.

  In the case of the second output form, the signal output through the right subtractor 93 is output to the lower left speaker 76, and the signal output through the left subtractor 94 is output to the upper right speaker 73.

  The listener switches the output form of the terminal 101 via the operation unit 14 depending on whether the horizontal listener is located on the right side or the left side. By switching the output form, the control unit 11 can listen to the crosstalk-cancelled sound when the listener operates the terminal 101 regardless of the position of the horizontal listener.

  In the first to third embodiments thus far, the longitudinal listener 28 and the right lateral listener 29 or the left lateral listener having the longitudinal direction as the Y axis and the lateral direction as the X axis. Two-dimensional explanations were given only to one of the two. However, the listener may be present in the Z-axis direction on condition that the listener is at the center of both the left and right of both speakers and is at the same distance from the terminal 1 as the other listeners.

  That is, when a listener exists on an arc that satisfies these conditions, the listener can listen to the crosstalk-cancelled sound according to the embodiment of the present invention at any position.

  As described above, in the crosstalk cancellation method of the present invention and the information communication terminal that has performed the crosstalk cancellation, a plurality of listeners can listen to the crosstalk canceled sound.

[Modification]
Next, a modification of the embodiment of the present invention will be described.

  FIG. 13 shows a terminal 102 in a modification of the embodiment of the present invention.

  The terminal 102 according to the modification of the embodiment of the present invention includes a speaker / receiver 77 and a speaker / receiver 77 that functions as a speaker.

  In the first to third embodiments of the present invention thus far, the signal a and the signal b are output from the audio processing unit 2 to the predetermined speaker in accordance with the speaker arranged at the predetermined location.

  In the terminal 102 in the modified example, the control unit 11 uses the speaker / receiver 77 to output one signal (for example, signal a) to the lower left speaker 76 and the other signal (for example, signal b) to the housing. The signal is output to the speaker / receiver 77 arranged at the upper right of the body 162.

  Here, audio reproduction is performed using a pair of the lower left speaker 76 and the speaker combined receiver 77.

  That is, in the terminal 102 shown in FIG. 13, the control unit 11 performs the same audio reproduction control as the terminal 100 according to the second embodiment of the present invention that performs audio reproduction using the lower left speaker 76 and the upper right speaker 73. Do.

  Here, the description is given on the assumption that the speaker / receiver 77 is arranged in the lower left speaker 76 and the upper right position that is diagonal to the lower left speaker.

  However, as shown in FIGS. 2, 8, and 11, as in the first to third embodiments of the present invention, the speaker and the speaker / receiver 77 may be arranged at any diagonal position. It does not matter if it is a position.

  Thus, in the modification of the embodiment of the present invention, it is possible to eliminate the mounting area for arranging a plurality of speakers by substituting the speaker combined receiver 77.

  Further, in the embodiment of the present invention, and the second and third embodiments and the modified examples, it has been described that these speakers are arranged at diagonal positions. Instead of diagonally, it may be an approximate position according to the design, or may be provided at four apex angles of a casing showing a quadrangle. In addition, the first casing 16, the first casing 160, the first casing 161, and the first casing 162 are disposed on a surface that is a side wall surface with respect to the surface on which the display unit 10 is disposed. The case has been described, but it may be arranged on the front and back of each housing.

  Further, the value of the third filter 85 (F3) for receiving the equivalent sound in the left and right ears described in the embodiment of the present invention is determined by the second embodiment and the third embodiment of the present invention. The present invention may be applied to the embodiments and modifications.

It is a perspective view of the terminal in an embodiment of the invention. It is a block diagram which shows the structure of the terminal of embodiment of this invention. It is a perspective view which shows the speaker position of the terminal for a comparison for comparing with the terminal of embodiment of this invention. It is an image figure which shows the relationship between two speakers of the terminal for a comparison, the signal processing circuit which performs the signal processing of crosstalk deletion, and a listener. It is the image figure which showed the terminal of embodiment of this invention, the standing position of a vertical listener, and a horizontal listener, and the sound signal which reaches | attains each user with the bird's-eye view. It is an image figure which shows the relationship between two speakers of the terminal of embodiment of this invention, the signal processing circuit which performs the signal processing of crosstalk deletion, and a longitudinal listener. It is a perspective view of the terminal in the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the terminal of the 2nd Embodiment of this invention. It is the image figure which showed the standing position of the terminal of the 2nd Embodiment of this invention, a vertical listener, and a horizontal listener, and the sound signal which reaches | attains each user with the bird's-eye view. It is an image figure which shows the relationship between two speakers of the terminal of embodiment of this invention, the signal processing circuit which performs the signal processing of crosstalk deletion, and a longitudinal listener. It is a perspective view of the terminal in the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the terminal of the 3rd Embodiment of this invention. It is a perspective view of the terminal of the modification of embodiment of this invention. It is an image figure which shows the position of the speaker in the conventional information communication terminal, and the difference in display content, (a) is an image figure when performing a vertical display, (b) is an image figure when performing a horizontal display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Information communication terminal 1 'Information communication terminal 100 Information communication terminal 101 Information communication terminal 102 Information communication terminal 2 Voice processing part 20 Voice processing part 3 Wireless communication part 4 Antenna 5 Microphone 6 Receiver 70 Speaker 71 Right speaker 72 Left speaker 73 Upper right speaker 74 Lower right speaker 75 Upper left speaker 76 Lower left speaker 77 Speaker combined receiver 81 First filter 82 Second filter 83 First filter 84 Second filter 85 Third filter 90 Subtractor 91 Right subtractor 92 Left subtractor 93 Right subtractor 94 Left subtractor 10 Display unit 10 'Display unit 11 Control unit 12 CPU
13 ROM (memory)
14 Operation unit 15 RAM (memory)
16 1st housing | casing 160 1st housing | casing 161 1st housing | casing 162 1st housing | casing 17 2nd housing | casing 170 2nd housing | casing 171 2nd housing | casing 172 2nd housing | casing 21 Signal Processing circuit 21 'Signal processing circuit 27 Listener 28 Vertical listener 29 Right side listener 30 Left side listener

Claims (13)

Including at least two or more speakers and a signal processing circuit having a plurality of filters for performing crosstalk elimination with respect to an input signal to be output to the two speakers.
The two speakers are arranged at diagonal positions with respect to a housing on which the speakers are mounted,
An audio playback device that performs audio playback by outputting signals processed by the signal processing circuit to the two speakers, respectively .
The first speaker is positioned at a lower right position from the diagonal center with respect to the casing, and the first speaker is positioned at an upper left position so that the speakers are positioned diagonally with respect to the longitudinal direction of the casing. 2 speakers,
The signal processing circuit includes:
A first filter that processes a portion of the second input signal output to the second speaker and outputs to the first speaker;
A second filter that performs processing on a part of the first input signal output to the first speaker and outputs the processed signal to the second speaker;
A second filter that performs processing on the second input signal to be output to the second speaker and outputs to the second speaker;
Transfer characteristics from the right and left ears of a longitudinal listener located in the longitudinal direction of the information communication terminal and located in the center of the left and right of the first speaker and the second speaker to the first speaker, respectively [ A], [A] ′, the transfer characteristics from the second speaker to the right and left ears of the vertical listener are [B] ′, [B], respectively, and the first, second, third An audio reproducing apparatus characterized by satisfying the relationship of [B] ′ · F3 = [A] · F1, and [A] ′ = [B] · F2 when the transfer characteristics of the filter are F1, F2, and F3. Including at least two or more speakers and a signal processing circuit having a plurality of filters for performing crosstalk elimination with respect to an input signal to be output to the two speakers.
The two speakers are arranged at diagonal positions with respect to a housing on which the speakers are mounted,
An audio playback device that performs audio playback by outputting signals processed by the signal processing circuit to the two speakers, respectively.
The first speaker is positioned at a lower left position from the diagonal center with respect to the casing, and the second speaker is positioned at an upper right position so that the speakers are diagonal to each other with respect to the longitudinal direction of the casing. Place the speaker
The signal processing circuit includes:
A first filter that processes a portion of the second input signal output to the second speaker and outputs to the first speaker;
A second filter that performs processing on a part of the first input signal output to the first speaker and outputs the processed signal to the second speaker;
A second filter that performs processing on the second input signal to be output to the second speaker and outputs to the second speaker;
Transfer characteristics from the right and left ears of a longitudinal listener located in the longitudinal direction of the information communication terminal and located in the center of the left and right of the first speaker and the second speaker to the first speaker, respectively [ A], [A] ′, the transfer characteristics from the second speaker to the right and left ears of the vertical listener are [B] ′, [B], respectively, and the first, second, third An audio reproducing apparatus characterized by satisfying the relationship of [B] ′ · F3 = [A] · F1, and [A] ′ = [B] · F2 when the transfer characteristics of the filter are F1, F2, and F3 . Including at least two or more speakers and a signal processing circuit having a plurality of filters for performing crosstalk elimination with respect to an input signal to be output to the two speakers.
The two speakers are arranged at diagonal positions with respect to a housing on which the speakers are mounted,
An audio playback device that performs audio playback by outputting signals processed by the signal processing circuit to the two speakers, respectively.
The speakers are arranged at the four corners of the casing so as to be diagonal to each other with respect to the longitudinal direction of the casing, and as a first output form, a diagonal center with respect to the casing. The speaker arranged at the lower right position is used as the first speaker, the speaker arranged at the upper left position is used as the second speaker, and as the second output form, the lower left position from the diagonal center with respect to the housing Including a control unit that performs control so that the speaker disposed at the upper right position is used as the first speaker and the speaker disposed at the upper right position is used as the second speaker.
The signal processing circuit includes:
A first filter that processes a portion of the second input signal output to the second speaker and outputs to the first speaker;
A second filter that performs processing on a part of the first input signal output to the first speaker and outputs the processed signal to the second speaker;
A second filter that performs processing on the second input signal to be output to the second speaker and outputs to the second speaker;
Transfer characteristics from the right and left ears of a longitudinal listener located in the longitudinal direction of the information communication terminal and located in the center of the left and right of the first speaker and the second speaker to the first speaker, respectively [ A], [A] ′, the transfer characteristics from the second speaker to the right and left ears of the vertical listener are [B] ′, [B], respectively, and the first, second, third An audio reproducing apparatus characterized by satisfying the relationship of [B] ′ · F3 = [A] · F1, and [A] ′ = [B] · F2 when the transfer characteristics of the filter are F1, F2, and F3 . The sound reproducing device according to any one of claims 1 to 3, wherein a speaker combined receiver is replaced with the first or second speaker . The audio reproduction device according to any one of claims 1 to 4, wherein the transfer characteristic F3 of the third filter satisfies F3 = [A] / [B] = [A] '/ [B]' . The receivers that are output from the first speaker and the second speaker to listeners located on the planes of the left and right centers of the first speaker and the second speaker and at an equal distance from the information communication terminal. The sound reproducing device according to any one of claims 1 to 5, wherein each of the listening sounds can be heard only by one ear of the listener . An information communication terminal including the audio reproduction device according to claim 1. At least two or more speakers arranged diagonally with respect to the housing, and an input signal supplied to two specific speakers out of the speakers, depending on the output of the two specific speakers Perform processing to delete the resulting crosstalk,
  An audio reproduction method for outputting processed signals to the two speakers, respectively.
The first speaker is positioned at a lower right position from the diagonal center with respect to the casing, and the first speaker is positioned at an upper left position so that the speakers are positioned diagonally with respect to the vertical direction of the casing. 2 speakers,
The two speakers include a first speaker and a second speaker,
  A first filter that performs processing on a part of the second input signal to be output to the second speaker and outputs to the first speaker;
A second filter that performs processing on a part of the first input signal output to the first speaker and outputs the processed signal to the second speaker;
  A second filter that performs processing on the second input signal to be output to the second speaker and outputs to the second speaker;
Transfer characteristics from the right and left ears of a longitudinal listener located in the longitudinal direction of the information communication terminal and located in the center of the left and right of the first speaker and the second speaker to the first speaker, respectively [ A], [A] ′, the transfer characteristics from the second speaker to the right and left ears of the vertical listener are [B] ′, [B], respectively, and the first, second, third An audio reproduction method characterized by satisfying the relationship of [B] ′ · F3 = [A] · F1, and [A] ′ = [B] · F2 when the transfer characteristics of the filter are F1, F2, and F3. At least two or more speakers arranged diagonally with respect to the housing, and an input signal supplied to two specific speakers out of the speakers, depending on the output of the two specific speakers Perform processing to delete the resulting crosstalk,
  An audio reproduction method for outputting processed signals to the two speakers, respectively.
The first speaker is positioned at a lower left position from the diagonal center and the second speaker is positioned at an upper right position with respect to the casing so that the speakers are positioned diagonally with respect to the vertical direction of the casing. Place the speaker
The two speakers include a first speaker and a second speaker,
  A first filter that performs processing on a part of the second input signal to be output to the second speaker and outputs to the first speaker;
A second filter that performs processing on a part of the first input signal output to the first speaker and outputs the processed signal to the second speaker;
  A second filter that performs processing on the second input signal to be output to the second speaker and outputs to the second speaker;
Transfer characteristics from the right and left ears of a longitudinal listener located in the longitudinal direction of the information communication terminal and located in the center of the left and right of the first speaker and the second speaker to the first speaker, respectively [ A], [A] ′, the transfer characteristics from the second speaker to the right and left ears of the vertical listener are [B] ′, [B], respectively, and the first, second, third An audio reproduction method characterized by satisfying the relationship of [B] ′ · F3 = [A] · F1, and [A] ′ = [B] · F2 when the transfer characteristics of the filter are F1, F2, and F3. At least two or more speakers arranged diagonally with respect to the housing, and an input signal supplied to two specific speakers out of the speakers, depending on the output of the two specific speakers Perform processing to delete the resulting crosstalk,
  An audio reproduction method for outputting processed signals to the two speakers, respectively.
The speakers are arranged at four corners of the casing so as to be diagonal to each other with respect to the vertical direction of the casing, and as a first output form from the diagonal center with respect to the casing. The speaker arranged at the lower right position is used as the first speaker, the speaker arranged at the upper left position is used as the second speaker, and the second output form is located at the lower left position from the diagonal center with respect to the housing. Control is performed so that the speaker disposed is used as the first speaker and the speaker disposed in the upper right position is used as the second speaker.
The two speakers include a first speaker and a second speaker,
  A first filter that performs processing on a part of the second input signal to be output to the second speaker and outputs to the first speaker;
A second filter that performs processing on a part of the first input signal output to the first speaker and outputs the processed signal to the second speaker;
  A second filter that performs processing on the second input signal to be output to the second speaker and outputs to the second speaker;
Transfer characteristics from the right and left ears of a longitudinal listener located in the longitudinal direction of the information communication terminal and located in the center of the left and right of the first speaker and the second speaker to the first speaker, respectively [ A], [A] ′, the transfer characteristics from the second speaker to the right and left ears of the vertical listener are [B] ′, [B], respectively, and the first, second, third An audio reproduction method characterized by satisfying the relationship of [B] ′ · F3 = [A] · F1, and [A] ′ = [B] · F2 when the transfer characteristics of the filter are F1, F2, and F3. The sound reproduction method according to any one of claims 8 to 10, wherein a speaker combined receiver is replaced with the first or second speaker. The audio reproduction method according to any one of claims 8 to 11, wherein the transfer characteristic F3 of the third filter satisfies F3 = [A] / [B] = [A] '/ [B]' . The receivers that are output from the first speaker and the second speaker to listeners located on the planes of the left and right centers of the first speaker and the second speaker and at an equal distance from the information communication terminal. The sound reproduction method according to any one of claims 8 to 12, wherein each of the listening sounds can be heard only by one ear of the listener .

Images