Patent Publication Number: US-9432767-B2

Title: Headphone with microphones that processes external sound pickup by the microphones and inputs external source sound signal

Description:
This application is a U. S. National Phase Application of PCT International Application PCT/JP2011/056864 filed on Mar. 22, 2011 which is based on and claims priority from JP 2010-065526 filed on Mar. 23, 2010 the contents of which is incorporated in its entirety by reference. 
     TECHNICAL FIELD 
     The present invention relates to a headphone which has a sound pickup function and through which a picked up sound is emitted in various modes. 
     BACKGROUND ART 
     Various headphones having sound pickup functions have been proposed. For example, a headphone disclosed in PTL 1 includes a speaker and a microphone provided in a pair, and the microphone is placed so as to be movable with respect to the speaker. Further, the microphone functions as a microphone for an external sound pickup in a mode in which the microphone, speaker and ear are arranged in this order, and functions as a microphone for noise cancellation in a mode in which the speaker, microphone and ear are arranged in this order. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP-A-2009-65456 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the headphone disclosed in PTL 1, the microphone merely serves to simply pick up an external sound in the mode in which the microphone functions as an external sound pickup microphone. On the other hand, in the mode in which the microphone functions as a noise cancellation microphone, the microphone merely serves to detect a noise included in a sound, which has been emitted from the speaker, until the sound reaches the ear. 
     Therefore, the above headphone is incapable of appropriately combining a sound inputted to the speaker from a different source with an external sound picked up by the microphone, and thus incapable of allowing the combined sound to be emitted from the speaker. 
     The present invention has been made in view of the above-described problems, and its object is to provide a headphone capable of processing an external sound picked up by a microphone and a source sound inputted from an external source, so that the external sound and source sound are appropriately combined with each other in accordance with a situation, and capable of emitting the combined sound from an integrally attached speaker in a sound emission mode responsive to the situation. 
     Solution to Problem 
     In order to achieve the object, according to the invention, there is provided a headphone comprising: a pair of earphone units each of which includes a speaker and a plurality of microphones which are arranged at a back side of the speaker in a given pattern and through which external sounds are picked up; a sound pickup signal generator configured to generate a plurality of sound pickup signals, each of which has a given directivity, by using a plurality of signals outputted from the plurality of microphones; an external source sound input section through which an external source sound signal from an external source is inputted; and a sound emission signal generator configured to generate sound emission signals, which are to be inputted to the speakers of the earphone units and each of which has a directivity, by using the external source sound signal and the plurality of sound pickup signals. 
     The headphone may further comprise a sound discriminator configured to make a discrimination between a noise included in the plurality of sound pickup signals and an effective sound, and the sound emission signal generator may generate the sound emission signals based on a result of the discrimination made by the sound discriminator. 
     The sound emission signal generator may suppress the noise and enhance the effective sound, to generate the sound emission signals. 
     When the effective sound is inputted, the sound emission signal generator may suppress the external source sound signal and generate sounds, which enhance the effective sound, by using the plurality of sound pickup signals, to generate the sound emission signals. 
     The sound emission signal generator may include a primary storage for primarily storing the effective sound, and output the sounds, which enhance the effective sound, after a given period of time from a timing of suppressing the external source sound signal. 
     The headphone may further comprise a non-sound information acquirer configured to acquire non-sound information, and the sound emission signal generator may process the sound emission signals based on the non-sound information. 
     The non-sound information may include information related to a time. 
     The non-sound information may include information related to a position. 
     The headphone may further comprise a non-sound information acquirer configured to acquire non-sound information, and the sound emission signal generator may generate the sound emission signals based on the non-sound information, the effective sound, and the external source sound signal. 
     The sound emission signal generator may perform frequency characteristic processing on the sound emission signals. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating a configuration of a headphone according to a first embodiment of the present invention. 
         FIGS. 2(A), 2(B) and 2(C)  are block diagrams illustrating a configuration of a directional sound pickup signal generator illustrated in  FIG. 1 . 
         FIGS. 3(A), 3(B) and 3(C)  are block diagrams illustrating a configuration of a sound emission signal generator illustrated in  FIG. 1 . 
         FIG. 4  is a block diagram illustrating a configuration of a headphone according to a second embodiment of the present invention. 
         FIG. 5  is a block diagram illustrating a configuration of a headphone according to a third embodiment of the present invention. 
         FIG. 6  is a block diagram illustrating a configuration of an overall adjuster in a case where sound pickup signals are used. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A headphone according to a first embodiment of the present invention will be described with reference to the drawings.  FIG. 1  is a block diagram illustrating a configuration of a headphone  1 A according to the first embodiment of the present invention. 
     The headphone  1 A includes a right ear contact casing  10 R, a left ear contact casing  10 L and a body  20 . The right ear contact casing  10 R is used in a state where the right ear contact casing  10 R is attached to a right ear RE of a user, and the left ear contact casing  10 L is used in a state where the left ear contact casing  10 L is attached to a left ear LE of the user. The body  20  is electrically connected to the right ear contact casing  10 R and the left ear contact casing  10 L. From a structural standpoint, for example, the body  20  may be incorporated into a casing of the headphone  1 A in which the right ear contact casing  10 R and the left ear contact casing  10 L are integral with each other, or the body  20  may be formed separately from the right ear contact casing  10 R and the left ear contact casing  10 L and connected thereto via a cord. 
     The right ear contact casing  10 R has a structure in which the right ear contact casing  10 R is fixed by being attached to the user&#39;s right ear RE, and includes external sound pickup microphones  121 RA and  121 RB, a headphone speaker  11 R and a noise cancellation microphone  122 R. 
     The external sound pickup microphones  121 RA and  121 RB are arranged at a back side of the headphone speaker  11 R. The back side corresponds to the opposite side of a sound emission side (front side) of the headphone speaker  11 R from which a sound is emitted. Specifically, the external sound pickup microphones  121 RA and  121 RB are arranged at the back side of the headphone speaker  11 R, thus picking up external sounds without picking up no sound emitted from the headphone speaker  11 R. For example, the external sound pickup microphones  121 RA and  121 RB are unidirectional microphones and placed so that respective maximum sound pickup sensitivity directions thereof are not parallel to each other and a given interval is provided therebetween. 
     The noise cancellation microphone  122 R is arranged at the front side of the headphone speaker  11 R. The noise cancellation microphone  122 R is placed so that its sound pickup direction corresponds to the direction of the speaker  11 R. 
     The external sound pickup microphones  121 RA and  121 RB pick up external sounds and convert the sounds into electrical signals, thus outputting sound pickup signals Smic 0 R and Smic 1 R. The noise cancellation microphone  122 R picks up a sound from the speaker  11 R and an external sound and converts the sounds into an electrical signal, thus outputting a noise cancellation signal SmicnR. The speaker  11 R emits a sound by being driven by a sound emission signal SoutR. 
     The left ear contact casing  10 L has a structure in which the left ear contact casing  10 L is fixed by being attached to the user&#39;s left ear LE, and includes external sound pickup microphones  121 LA and  121 LB, a headphone speaker  11 L and a noise cancellation microphone  122 L. 
     The external sound pickup microphones  121 LA and  121 LB are arranged at a back side of the headphone speaker  11 L. The back side corresponds to the opposite side of a sound emission side (front side) of the headphone speaker  11 L from which a sound is emitted. Specifically, the external sound pickup microphones  121 LA and  121 LB are arranged at the back side of the headphone speaker  11 L, thus picking up external sounds without picking up no sound emitted from the headphone speaker  11 L. For example, the external sound pickup microphones  121 LA and  121 LB are unidirectional microphones and placed so that respective maximum sound pickup sensitivity directions thereof are not parallel to each other and a given interval is provided therebetween. 
     The noise cancellation microphone  122 L is arranged at the front side of the headphone speaker  11 L. The noise cancellation microphone  122 L is placed so that its sound pickup direction corresponds to the direction of the speaker  11 L. 
     The external sound pickup microphones  121 LA and  121 LB pick up external sounds and convert the sounds into electrical signals, thus outputting sound pickup signals Smic 0 L and Smic 1 L. The noise cancellation microphone  122 L picks up a sound from the speaker  11 L and an external sound and converts the sounds into an electrical signal, thus outputting a noise cancellation signal SmicnL. The speaker  11 L emits a sound by being driven by a sound emission signal SoutL. 
     The body  20  includes a directional sound pickup signal generator  30 R, a directional sound pickup signal generator  30 L, an analyzer  40 , a sound emission signal generator  50 , and an external source sound signal generator  60 . 
     The directional sound pickup signal generator  30 R and the directional sound pickup signal generator  30 L are configured in the same manner, although the directional sound pickup signal generator  30 R performs processing on sound pickup signals for the right ear and the directional sound pickup signal generator  30 L performs processing on sound pickup signals for the left ear. Accordingly, only the directional sound pickup signal generator  30 R for the right ear will be specifically described below. 
       FIGS. 2(A), 2(B) and 2(C)  are block diagrams illustrating a configuration of the directional sound pickup signal generator  30 R.  FIG. 2(A)  is a block diagram of the directional sound pickup signal generator  30 R, and  FIGS. 2(B) and 2(C)  are block diagrams of individual bearing sound pickup signal generators  300 A and  300 A′, respectively. 
     The directional sound pickup signal generator  30 R includes the individual bearing sound pickup signal generators  300 A to  300 N. Note that a case where the directional sound pickup signal generator  30 R includes the individual bearing sound pickup signal generators, the number of which corresponds to  300 A to  300 N, has been described below; however, the number of the individual bearing sound pickup signal generators may be appropriately set in accordance with necessary bearing resolution. More specifically, the number of the individual bearing sound pickup signal generators may be set so that an individual bearing sound pickup signal is generated for each desired angle for bearing resolution in an angular range of 180° corresponding to the right ear in a horizontal plane. 
     The sound pickup signals Smic 0 R and Smic 1 R from the external sound pickup microphones  121 RA and  121 RB are inputted to each of the individual bearing sound pickup signal generators  300 A to  300 N. 
     Based on the sound pickup signals Smic 0 R and Smic 1 R, the individual bearing sound pickup signal generators  300 A to  300 N generate directional sound pickup signals SchA to SchN having directivities at different maximum sound pickup sensitivities. 
     Specifically, the individual bearing sound pickup signal generators  300 A to  300 N each have the configuration illustrated in  FIG. 2(B)  or  FIG. 2(C) . Note that the individual bearing sound pickup signal generators  300 A to  300 N are configured in the same manner, although only the formed directivities thereof are different; therefore, the individual bearing sound pickup signal generator  300 A will be described by way of example. 
     (i) When a Process for Adding Up and Combining Sound Pickup Signals is Used 
     The individual bearing sound pickup signal generator  300 A illustrated in  FIG. 2(B)  includes filter sections  311  and  312 , and an adder  313 . The filter section  311  performs a given filtering process on the sound pickup signal Smic 0 R and outputs the resulting signal to the adder  313 . The filter section  312  performs a given filtering process on the sound pickup signal Smic 1 R and outputs the resulting signal to the adder  313 . The filter sections  311  and  312  perform gain adjustment or delay adjustment on the sound pickup signals in order to realize desired directivities, for example. The adder  313  adds up the sound pickup signals Smic 0 R and Smic 1 R on which the filtering processes have been performed, thus generating the individual bearing sound pickup signal SchA. 
     (ii) When Processing is Used by Means of a Coefficient that is Based on Sound Pickup Signals 
     The individual bearing sound pickup signal generator  300 A′ illustrated in  FIG. 2(C)  includes a coefficient decider  314  and a multiplier  315 . Based on the sound pickup signals Smic 0 R and Smic 1 R, the coefficient decider  314  decides a coefficient for processing the directivity of the sound pickup signal Smic 0 R. For example, using the sound pickup signals Smic 0 R and Smic 1 R, coefficient deciding signals for different directivities are generated. Then, using a ratio or the like between the coefficient deciding signals, a coefficient by which a high sensitivity is obtained in a range that is steep and narrow in a desired bearing is decided. The multiplier  315  multiplies the sound pickup signal Smic 0 R by the coefficient, thereby generating an individual bearing sound pickup signal SchA′ having a maximum sound pickup sensitivity and a narrow directivity in a desired bearing. 
     The right individual bearing sound pickup signals SchA to SchN generated by the directional sound pickup signal generator  30 R are inputted to the sound emission signal generator  50 . Further, the left individual bearing sound pickup signals SchA to SchN, generated by the directional sound pickup signal generator  30 L in the same manner as those generated by the directional sound pickup signal generator  30 R, are also inputted to the sound emission signal generator  50 . Furthermore, the right and left individual bearing sound pickup signals SchA to SchN are also inputted to the analyzer  40 . 
     The analyzer  40  analyzes the right and left individual bearing sound pickup signals SchA to SchN. Specifically, in the analyzer  40 , a threshold value for the level of each of the individual bearing sound pickup signals SchA to SchN is set; thus, the analyzer  40  determines the signal as an effective sound when the level is equal to or higher than the threshold value, and determines the signal as a noise when the level is lower than the threshold value. Note that the threshold value is settable by the user. Further, based on the level of each of the individual bearing sound pickup signals SchA to SchN, which has been determined as an effective sound, the analyzer  40  detects a direction in which the effective sound has arrived. Using the determination results and detection results as analysis results, the analyzer  40  generates sound emission control information from the analysis results, and outputs the information to the sound emission signal generator  50 . 
     The sound emission signal generator  50  includes: a sound emission signal generator  50 R for the right ear; and a sound emission signal generator  50 L for the left ear, and generates the sound emission signals SoutR and SoutL based on the right and left individual bearing sound pickup signals SchA to SchN and the sound emission control information. The sound emission signal generator  50 R generates the right sound emission signal SoutR based on the right individual bearing sound pickup signals SchA to SchN and the sound emission control information. The sound emission signal generator  50 L generates the left sound emission signal SoutL based on the left individual bearing sound pickup signals SchA to SchN and the sound emission control information. 
     Note that the sound emission signal generator  50 R and the sound emission signal generator  50 L have the same block configuration, although the sound emission signal generator  50 R performs sound processing for the right ear and the sound emission signal generator  50 L performs sound processing for the left ear. Hence, similarly to the description of the foregoing directional sound pickup signal generator, only the right ear sound processing performed by the sound emission signal generator  50 R will be specifically described. 
       FIGS. 3(A), 3(B) and 3(C)  are block diagrams illustrating a configuration of the sound emission signal generator  50 R.  FIG. 3(A)  is a block diagram illustrating the configuration of the sound emission signal generator  50 R,  FIG. 3(B)  is a block diagram illustrating a configuration of a sound pickup signal individual adjuster  500 M of an individual adjuster  500  illustrated in  FIG. 3(A) , and  FIG. 3(C)  is a block diagram illustrating a configuration of an overall adjuster  510  illustrated in  FIG. 3(A) . 
     The sound emission signal generator  50 R includes the individual adjuster  500  and the overall adjuster  510 . The individual adjuster  500  includes the sound pickup signal individual adjuster  500 M and an external source sound signal individual adjuster  500 W. The sound pickup signal individual adjuster  500 M performs signal adjustment for each of the individual bearing sound pickup signals SchA to SchN. The external source sound signal individual adjuster  500 W performs signal adjustment for each channel of an external source sound signal Sway. Only parameters set in the external source sound signal individual adjuster  500 W are different from those set in the sound pickup signal individual adjuster  500 M, and the external source sound signal individual adjuster  500 W has the same configuration as the sound pickup signal individual adjuster  500 M. Accordingly, only the sound pickup signal individual adjuster  500 M will be described in more detail. 
     The sound pickup signal individual adjuster  500 M includes individual signal processors  501 A to  501 N and an adder  502 . Only parameters set in the individual signal processors  501 A to  501 N are different, and the individual signal processors  501 A to  501 N have the same configuration. Each of the individual signal processors  501 A to  501 N includes an equalizer (EQ), a gain adjuster, and a delay processor. For example, the individual signal processor  501 A includes an equalizer  505 A (described as “EQ” in the diagram), a gain adjuster  506 A and a delay processor  507 A. In each of the equalizer  505 A, the gain adjuster  506 A and the delay processor  507 A, a parameter for the individual bearing sound pickup signal SchA is set based on the sound emission control information, and a signal adjustment process is carried out in accordance with the parameter. 
     The adder  502  adds up the individual bearing sound pickup signals SchA to SchN on which the signal adjustment processes have been performed by the respective individual signal processors  501 A to  501 N, and thus generates a base sound emission signal Scm. The base sound emission signal Scm is inputted to the overall adjuster  510 . 
     The overall adjuster  510  includes an adder  514 , an equalizer  511  (described as “EQ” in the diagram), a gain adjuster  512 , and a noise cancellation processor  513 . The adder  514  adds up the base sound emission signal Scm and a base source sound signal Swc to combine the signals with each other, and outputs the combined sound emission signal to the equalizer  511 . Also in each of the equalizer  511  and the gain adjuster  512 , a parameter is set based on the sound emission control information, and a signal adjustment process is carried out on the combined sound emission signal in accordance with the parameter. 
     The noise cancellation processor  513  (described as “NC PROCESSOR” in the diagram) performs a known noise cancellation process by using: the combined sound emission signal on which equalizer processing and gain adjustment have been performed; and the noise cancellation signal SmicnR provided from the noise cancellation microphone  122 R, and thus outputs the sound emission signal SoutR. The sound emission signal SoutR is provided to the headphone speaker  11 R of the right ear contact casing  10 R, and the resulting sound is emitted to the user&#39;s right ear RE from the headphone speaker  11 R. 
     The use of the above-described configuration enables generation of sound emission signals in the following mode. 
     (Use Mode A) 
     In a first mode, while a source sound signal is mainly emitted, an effective sound, for example, is emitted in an interrupted manner when necessary. 
     An external reproducing device  200  includes an operation input section  202  and an external source  201 . Upon reception of an operation input for external source reproduction by the operation input section  202 , information of the operation input is provided to the analyzer  40 . At the same time, music data stored in the external source  201  is read and transmitted to the external source sound signal generator  60 . 
     Upon reception of the operation input for external source reproduction, the analyzer  40  generates sound emission control information indicative of the first mode, and provides the information to the sound emission signal generator  50 . Further, as mentioned above, the threshold value for the level of each of the individual bearing sound pickup signals SchA to SchN is set in the analyzer  40 ; thus, the analyzer  40  detects, as an effective sound signal, the signal having a level equal to or higher than the threshold value, and outputs sound emission control information indicative of existence of the effective sound signal to the sound emission signal generator  50 . 
     The external source sound signal generator  60  outputs an external source sound signal, which is based on the music data, to the sound emission signal generator  50 . 
     Upon reception of the sound emission control information indicative of the first mode, the sound emission signal generator  50  generates, by the external source sound signal individual adjuster  500 W, the base source sound signal Swc having sound quality for which an instruction has been provided by the operation input section  202 . In this case, when the sound emission control information indicative of existence of an effective sound has not been received, the sound emission signal generator  50  performs, by the sound pickup signal individual adjuster  500 M, sound level control so as to suppress the level of the base sound emission signal Scm. 
     Besides, upon reception of the sound emission control information indicative of existence of an effective sound, the sound emission signal generator  50  generates, by the sound pickup signal individual adjuster  500 M, the base sound emission signal Scm that enhances the effective sound. At the same time, upon reception of the sound emission control information indicative of the effective sound, the sound emission signal generator  50  performs, by the external source sound signal individual adjuster  500 W, sound level control so as to suppress the level of the base source sound signal Swc. 
     By performing the above-described processing, only a source sound having sound quality desired by the user is audible to the user while an ambient sound is suppressed in a steady state; on the other hand, only when an effective sound such as a hailing sound is produced, the source sound is suppressed, so that the effective sound is more clearly audible to the user. In this case, the effective sound is set to have a directivity, and therefore, the effective sound is audible to the user in such a manner that the user can also easily perceive a direction in which the effective sound has arrived. 
     Note that a delay process is performed on the base sound emission signal Scm by the sound pickup signal individual adjuster  500 M, thereby making it possible to provide a given time interval between source sound signal suppression timing and effective sound start timing. As a result, the source sound signal and effective signal are more reliably prevented from overlapping each other, and furthermore, the effective sound is easily audible to the user. Moreover, in this case, a speech rate conversion process may also be performed on the base sound emission signal Scm. 
     Further, in the above description, the control for suppressing the level of the base source sound signal Swc is performed only when the effective sound is detected, and the analyzer  40  decides sound emission control information with reference to the individual bearing sound pickup signals SchA to SchN as described in the foregoing embodiment. In this case, since the individual bearing sound pickup signals SchA to SchN each have directivity information, sound emission control information may be decided based on the directivity information. For example, only an individual bearing sound pickup signal from a bearing inputted in advance by an operation section or the like, or more specifically only an individual bearing sound pickup signal from the rear, may be added to and combined with the base source sound signal Swc. As a result, irrespective of existence or non-existence of an effective sound, the base source sound signal Swc is audible to the user while only a sound from a particular bearing (e.g., from the rear) is included in the base source sound signal Swc at all times. 
     Next, a headphone according to a second embodiment will be described with reference to the following diagram.  FIG. 4  is a block diagram illustrating a configuration of a headphone  1 B according to the second embodiment of the present invention. The headphone  1 B according to the present embodiment differs from the headphone  1 A described in the first embodiment in that a time measurement section  71  serving as a non-sound information acquirer is provided. Accordingly, only points different from the first embodiment will be specifically described below. 
     The time measurement section  71  measures time and provides time information to the analyzer  40 . The analyzer  40  generates sound emission control information based on the time information, and provides the sound emission control information to the sound emission signal generator  50 . Examples of the sound emission control information in this case include information for reducing the sound level and information for increasing the sound level. The sound emission signal generator  50  performs control for reducing or increasing the sound levels (levels) of the sound emission signals SoutR and SoutL in accordance with the sound emission control information. 
     The use of the above-described configuration enables generation of sound emission signals in the following mode. 
     (Use Mode B) 
     An operation input for carrying out a second mode is performed by an unillustrated operation section, and the analyzer  40  receives the operation input; then, the following processing is carried out. 
     When the second mode is received, the analyzer  40  acquires the time information from the time measurement section  71 . The analyzer  40  generates sound emission control information based on: information of operation start time and operation end time set upon reception of a sleep mode, for example; and the time information provided from the time measurement section  71 . The sound emission control information includes: level reduction start timing information; level reduction rate information; and sound emission end timing information. 
     Based on the sound emission control information, the sound emission signal generator  50  performs a process for gradually reducing, at given timing, the level of the combined sound emission signal of the base sound emission signal Scm and the base source sound signal Swc, and for completely suppressing the level after a lapse of a given period of time. As a result, sound emission is enabled in such a manner that the levels of the sound emission signals SoutR and SoutL are gradually reduced. Note that when the level of the base sound emission signal Scm is not the level of an effective sound, the base sound emission signal Scm may be further suppressed, and the level suppression process may be performed only on the base source sound signal Swc. In such a case, the sound emission signal generator  50  may perform the process based on the effective sound determination result provided from the analyzer  40 . 
     When the above-described processing is performed, the source sound and ambient sound gradually become inaudible to the user, thus making it possible to provide a pseudo-sleep state. 
     Further, contrary to the above-described process for gradually reducing the level of the base sound emission signal Scm, a process for gradually increasing the level of the base sound emission signal Scm may be performed. As a result, the ambient sound becomes audible to the user in such a manner that the ambient sound is gradually increased, thus making it possible to provide a pseudo-waking state. 
     Furthermore, a filtering processor is added to the sound emission signal generator  50 , thus enabling emission of sounds of the sound emission signals SoutR and SoutL which are mainly low frequency band sounds, while gradually reducing the levels thereof. As a result, a more pseudo-sleep state can also be provided. 
     Moreover, although the example in which only the base sound emission signal Scm is used has been described based on the configuration of the headphone according to the first embodiment in the foregoing description, the configuration of the headphone according to the second embodiment may be applied, and a combined sound signal of the base source sound signal Swc and the base sound emission signal Scm may be used. 
     Besides, although the example in which sound emission control information is set based only on time information has been described in the foregoing description, an additional process may be performed based on an effective sound detection result. For example, when an effective sound whose level is equal to or higher than a given level is picked up from a given bearing, the effective sound may be emitted in an interrupted manner. In that case, the sound level of the effective sound is preferably gradually increased. 
     Next, a headphone according to a third embodiment will be described with reference to the following diagram.  FIG. 5  is a block diagram illustrating a configuration of a headphone  1 C according to the third embodiment of the present invention. The headphone  1 C according to the present embodiment differs from the headphone  1 A described in the first embodiment in that a sensor  72  serving as a non-sound information acquirer is provided. Accordingly, only points different from the first embodiment will be specifically described below. 
     The sensor  72  senses non-sound information such as positional information or attitude of the headphone  1 B, and provides the non-sound information to the analyzer  40 . The analyzer  40  generates sound emission control information based on the non-sound information, and provides the sound emission control information to the sound emission signal generator  50 . Examples of the sound emission control information in this case include sound processing information and mixing information obtained based on the non-sound information. The sound emission signal generator  50  processes combined sound signals of the base sound emission signals Scm and the base source sound signals Swc in accordance with the sound emission control information, and outputs the sound emission signals SoutR and SoutL. Note that examples of the non-sound information sensed by the sensor  72  also include motion-related information and bearing-related information in addition to the position-related information and information related to the attitude of the headphone  1 B. 
     The use of the above-described configuration enables generation of sound emission signals in the following mode. 
     (Use Mode C) 
     An operation input for carrying out a third mode is performed by an unillustrated operation section, and the analyzer  40  receives the operation input; then, the following processing is carried out. The following description will be made using an example in which positional information is used as non-sound information and new sound signals are generated in accordance with the positional information. 
     When the third mode is received, the analyzer  40  acquires positional information from the sensor  72 . Upon acquisition of the positional information, the analyzer  40  acquires sound information associated with the positional information in advance. The sound information may be stored in a memory incorporated into the headphone  1 C in advance, or an external communication means may be provided so that the sound information is acquired from outside through information communication. Along with the acquired sound information, sound emission control information, by which the sound information is further combined with the combined sound emission signals of the base sound emission signals Scm and the base source sound signals Swc, is provided to the sound emission signal generator  50  by the analyzer  40 . 
     The sound emission signal generator  50  further combines the sound information with the combined sound emission signals based on the sound emission control information, thus generating and outputting the sound emission signals SoutR and SoutL. As a result, the particular sound emission signals SoutR and SoutL responsive to the position can be provided to the user. In other words, the user can enjoy a sound responsive to a location, or can grasp location-related information by the sound. 
     Note that a method for combining the base source sound signal Swc with the base sound emission signal Scm may be changed based on the sound emission control information. 
     In each of the foregoing embodiments, the noise cancellation signals SmicnR and SmicnL provided from the noise cancellation microphones  122 R and  122 L are used for the noise cancellation process; however, the sound pickup signals Smic 0 R, Smic 1 R, Smic 0 L and Smic 1 L provided from the external sound pickup microphones  121 RA,  121 RB,  121 LA and  121 LB may alternatively be used.  FIG. 6  is a block diagram illustrating a configuration of an overall adjuster  510 ″ in a case where the sound pickup signals Smic 0 R and Smic 1 R are used. Also in  FIG. 6 , only a circuit configuration of the overall adjuster  510 ″, corresponding to the right ear, is illustrated similarly to the foregoing description, and the following description will be made on the right ear side circuit configuration. Note that similar configuration and processing may also be applied to a left ear side circuit configuration. 
     As illustrated in  FIG. 6 , the overall adjuster  510 ″ in this case further includes a noise cancellation signal generator  515  (described as “NC SIGNAL GENERATOR” in the diagram) in addition to the components of the above-described overall adjuster  510 . The noise cancellation signal generator  515  generates a noise cancellation signal by using the sound pickup signals Smic 0 R and Smic 1 R. A noise cancellation processor  513 ′ carries out a noise cancellation process by using: the noise cancellation signal that is based on the sound pickup signals Smic 0 R and Smic 1 R; and the noise cancellation signal SmicnR. 
     Also with the use of the above-described method, the noise cancellation process can be reliably carried out. 
     Note that although the noise cancellation process is invariably performed in the foregoing description, a configuration in which no noise cancellation process is performed depending on a situation may be used. 
     Furthermore, although the example in which two right external sound pickup microphones and two left external sound pickup microphones are used has been described in the foregoing description, it is only necessary to use a plurality of right external sound pickup microphones and a plurality of left external sound pickup microphones. Moreover, when three or more right external sound pickup microphones and three or more left external sound pickup microphones are three-dimensionally arranged, spatial bearing resolution can be obtained. 
     According to an aspect of the invention, a plurality of directional sound pickup signals having directivities for a plurality of different bearings are generated from sound pickup signals obtained by a plurality of microphones placed at aback side of a speaker. Further, using an external source sound signal supplied from an external source and the plurality of directional sound pickup signals obtained by the microphones, more various sound emission signals are generated. For example, while an external source sound is emitted, directional sound signals, which are based on the sound pickup signals obtained by the microphones, can be emitted in such a manner that the directional sound signals are appropriately mixed with the external source sound signal in accordance with a situation. 
     According to an aspect of the invention, in order to produce a sound emission signal, a discrimination is made between an effective sound such as a person&#39;s hailing sound or a broadcast sound and a noise (such as a white noise). As a result, a distinction can be made between the effective sound and noise in performing processing, the result of which can be reflected on the sound emission signal. 
     According to an aspect of the invention, a noise is suppressed and an effective sound is enhanced. As a result, the noise is interrupted and only the effective sound such as a person&#39;s hailing sound or a broadcast sound is combined with an external source sound, so that the resulting sound is audible to the user. In this case, since the effective sound is produced in such a manner that the effective sound has a directivity, the effective sound is emitted so as to be heard from the direction in which the effective sound has arrived. Consequently, even while an external source sound is heard in a steady state, upon arrival of an effective sound from outside, the effective sound is audible in such a manner that the user can perceive the direction in which the effective sound has arrived. 
     According to an aspect of the invention, an external source sound signal is emitted in a steady state, and only when an effective sound exists, the effective sound can be enhanced and emitted while the external source sound signal is suppressed. As a result, for example, even while the user listens to music, a necessary sound from outside is reliably audible in such a manner that the user perceives the direction in which the sound has arrived. 
     According to an aspect of the invention, the timing of effective sound emission is delayed by a given time relative to that of start of external source sound signal suppression. As a result, it is difficult for an effective sound to be buried in an external source sound, and the effective sound is more clearly audible. 
     According to an aspect of the invention, sound emission signals are processed by using non-sound information. Examples of the non-sound information include the above-mentioned time and position, and headphone attitude, and also include data information when an external communication function is provided. When sound emission signals are generated based on information other than sound information in this manner, sound emission signals can be generated in more various modes. 
     According to an aspect of the invention, frequency characteristic processing is performed on sound emission signals, thus making it possible to generate sound emission signals in various modes. 
     According to an aspect of the invention, a headphone including a microphone is capable of performing, in accordance with a situation, appropriate processing on an external sound picked up by the microphone and a source sound provided from an external source, and capable of emitting a sound from a speaker in various sound emission modes responsive to the situation.