JP2015126527A - Loudspeaker device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loudspeaker device capable of clearly localizing a sound source while suppressing the variation of sound quality using a sound having directivity and localization by a virtual sound source.SOLUTION: An audio signal subjected to filtering by a head-related transfer function in a virtual processing part 40 is inputted to a woofer 33L and a woofer 33R. A bandwidth processing part 45 inputs only a bandwidth equal to or more than a frequency F1 (for example, 400 Hz) to the virtual processing part 40. Thereby, the variation of sound quality can be suppressed. A frequency bandwidth contributing to a sense of localization in the head-related transfer function is mainly about several hundred kHz, and the sense of localization is almost maintained even when a signal of less than several hundreds Hz is not inputted. Accordingly, an array loudspeaker device 2 can compensate a sense of localization by a sound beam at a sense of localization by a virtual sound source and clearly localizes a sound source while suppressing the variation of sound quality.

Description

  The present invention relates to a speaker device that outputs sound for localizing a sound source.

  2. Description of the Related Art Conventionally, there is known an array speaker device that outputs a sound beam having directivity by delaying an audio signal and distributing it to a plurality of speaker units (see Patent Document 1).

  The array speaker device disclosed in Patent Document 1 localizes an actual sound source on a wall surface or the like by reflecting the sound beam of each channel to a wall and reaching it from around the listener.

  Further, the array speaker device of Patent Document 1 performs a process of localizing a virtual sound source by performing a filter process based on a head-related transfer function for a channel that cannot reach an audio beam due to the shape of a room or the like. .

JP2008-227803

  A virtual sound source cannot provide a sense of distance compared to a real sound source such as an audio beam. Further, in the localization using the virtual sound source, if the listening position deviates from the specified position, the localization feeling becomes weak, so that the region where the localization feeling can be obtained is narrow. Further, since the head-related transfer function is set based on the shape of the model head, there is an individual difference in the sense of localization. Further, the filtering process based on the head-related transfer function changes the quality of the original audio signal, so that there is a change in sound quality.

  Therefore, an object of the present invention is to provide a speaker device that can clearly localize a sound source while suppressing a change in sound quality by using localization based on a real sound source and a virtual sound source.

  The speaker device of the present invention includes a first sound emitting unit that outputs a sound based on an input audio signal, a localization adding unit that performs a filtering process on the input audio signal based on a head-related transfer function, and the localization adding unit. And a second sound emitting unit that outputs a sound based on the audio signal filtered in step B, and a band processing unit that limits a frequency band of the audio signal input to the localization adding unit.

  As described above, the speaker device according to the present invention has a mode in which a virtual sound source compensates the localization feeling due to a real sound source such as an audio beam or a surround speaker. Thereby, a feeling of localization can be improved as compared with a case where localization is performed using only a real sound source such as an audio beam or a case where localization is performed using only a virtual sound source. In the speaker device of the present invention, the band in which the filtering process using the head-related transfer function is performed is limited. Since the filtering process based on the head-related transfer function changes the characteristics of the original audio signal, there is a change in sound quality. Therefore, if the filtering process using the head-related transfer function is performed in the entire band, the change in sound quality becomes conspicuous. However, since the array speaker device of the present invention limits the band for performing the filter processing by the head-related transfer function, it is possible to suppress the change in sound quality. In particular, the frequency band that contributes to a sense of localization in the head-related transfer function is mainly about several kHz, and even when a signal of less than several hundred Hz is not input, the sense of localization does not change substantially. Therefore, by limiting the band for performing the filter processing by the head-related transfer function, it is possible to supplement the sense of localization by the real sound source while suppressing the change in sound quality, and to clearly localize the sound source.

  The speaker device of the present invention may further include a subwoofer, and the band processing unit may be configured such that a lower limit frequency of a band through which an audio signal passes is higher than an upper limit frequency of the subwoofer. The upper limit frequency of the subwoofer is a very low frequency of about several tens Hz to 200 Hz. The speaker device of the present invention performs the filtering process using the head-related transfer function in a band higher than the upper limit frequency band (about several tens of Hz to 200 Hz) of the subwoofer, so that the sound output from the subwoofer and the sound after filtering There is no overlap in bandwidth. Therefore, it is possible to prevent the sound output from the subwoofer and the filtered sound from interfering with each other, and to suppress a change in sound quality.

  The second sound emitting unit includes a speaker unit having a lower limit frequency lower than the lower limit frequency of the first sound emitting unit, and an audio signal lower than the lower limit frequency of the first sound emitting unit is provided to the woofer. It is good also as an aspect inputted. That is, the low frequency range in which the first sound emitting unit cannot be output is reinforced by using a speaker unit to which an audio signal after filtering by the head-related transfer function is input as a woofer.

  The speaker device includes an input unit for inputting an audio signal, divides a frequency band of the audio signal input to the input unit, inputs an audio signal on a high frequency side to the first sound emitting unit, It is good also as an aspect provided with the zone | band division | segmentation part which inputs the audio | voice signal by the side into the said 2nd sound emission part. In other words, an audio signal in a low frequency band (less than several hundred Hz) that is not necessary for outputting a sound having directivity is not input to the first sound emission unit, and the audio signal in the low frequency band is output in the second emission. Input to the sound side. As a result, the sound source can be clearly localized while reinforcing the low-frequency sound.

  In the band processing unit, the lower limit frequency of the band through which the audio signal passes is preferably the same as or close to the frequency divided by the band dividing unit.

  As a result, the frequency band of the audio signal after the filtering process does not overlap with the divided low frequency band of the original audio signal. Therefore, the frequency band of the filtered audio signal and the divided low frequency band of the original audio signal do not interfere with each other, and a change in sound quality can be suppressed.

  Note that the first sound emitting unit can be realized by, for example, a surround speaker installed around the listening position, and an input audio signal can be obtained using a speaker array in which a plurality of speakers are arranged. It can also be realized by outputting a sound beam by delaying and distributing to a plurality of speakers.

  The speaker device of the present invention can clearly localize a sound source while suppressing a change in sound quality by using localization by a real sound source and localization by a virtual sound source.

It is the schematic which shows the structure of AV system. It is a block diagram which shows the structure of an array speaker apparatus. It is a block diagram which shows the structure of a filter process part. It is a block diagram which shows the structure of a beamization process part. It is a figure explaining the sound field which the array speaker apparatus 2 produces | generates. It is a block diagram which shows the structure of a virtual processing part. It is a block diagram which shows the structure of a localization addition part and a correction | amendment part. It is the conceptual diagram which showed the zone | band of the audio signal input into each speaker unit. It is the schematic which shows the structure of the AV system which concerns on the modification 1. FIG. 10 is a block diagram illustrating a configuration of an array speaker device according to Modification 1. It is a block diagram which shows the structure of the array speaker apparatus which concerns on the modification 2. 10 is a block diagram illustrating configurations of a bandwidth processing unit and an addition processing unit according to Modification 2. FIG. It is a block diagram which shows the structure of the array speaker apparatus which concerns on the modification 3. FIG. 10 is a block diagram illustrating a configuration of a band dividing unit according to Modification 3. It is the conceptual diagram which showed the zone | band of the audio signal input into each speaker unit. It is the schematic which shows the array speaker apparatus which concerns on the modification 4. It is a figure which shows the example which localizes a real sound source with a surround speaker.

  FIG. 1 is a schematic diagram of an AV system 1 including an array speaker device 2 according to the present embodiment. The AV system 1 includes an array speaker device 2 and a television 4. The array speaker device 2 is connected to the television 4. The array speaker device 2 receives an audio signal corresponding to an image reproduced on the television 4 and an audio signal from a content player (not shown).

  As shown in FIG. 1, the array speaker device 2 includes, for example, a rectangular parallelepiped housing, and is installed in the vicinity of the television 4 (lower portion of the display screen of the television 4). The array speaker device 2 includes, for example, 16 speaker units 21A to 21P, a woofer 33L, and a woofer 33R on the front surface (the surface facing the listener).

  The speaker units 21A to 21P are arranged in a line along the horizontal direction when viewed from the listener. The speaker unit 21A is disposed on the leftmost side when viewed from the listener, and the speaker unit 21P is disposed on the rightmost side when viewed from the listener. The woofer 33L is disposed further to the left of the speaker unit 21A. The woofer 33R is disposed on the right side of the speaker unit 21P.

  In this example, the speaker array including the speaker units 21A to 21P corresponds to the first sound emitting unit of the present invention, and the woofer 33L and the woofer 33R correspond to the second sound emitting unit of the present invention.

  Note that the number of speaker units is not limited to 16, and may be, for example, 8 or the like. Also, the arrangement is not limited to the example in which the arrangement is arranged in one row along the horizontal direction, and for example, the arrangement may be arranged in three rows along the horizontal direction.

  FIG. 2 is a block diagram showing a configuration of the array speaker device 2. The array speaker device 2 includes an input unit 11, a decoder 10, a band dividing unit 14, a band processing unit 45, a beamization processing unit 20, an addition processing unit 32, and a virtual processing unit 40.

  The input unit 11 includes an HDMI receiver 111, a DIR 112, and an A / D conversion unit 113. The HDMI receiver 111 inputs an HDMI signal conforming to the HDMI standard and outputs it to the decoder 10. The DIR 112 receives a digital audio signal (SPDIF) and outputs it to the decoder 10. The A / D converter 113 receives an analog audio signal, converts it into a digital audio signal, and outputs it to the decoder 10.

  The decoder 10 is a DSP and decodes an input signal. The decoder 10 inputs signals in various formats such as AAC (registered trademark), Dolby Digital (registered trademark), DTS (registered trademark), MPEG-1 / 2, MPEG-2 multichannel, MP3, etc. It is converted into an audio signal (digital audio signal of FL channel, FR channel, C channel, SL channel, and SR channel. Hereinafter, when simply referred to as an audio signal, the digital audio signal is indicated) and output. A thick solid line shown in FIG. 2 indicates a multi-channel audio signal. The decoder 10 also has a function of expanding, for example, a stereo channel audio signal to a multi-channel audio signal.

  The multichannel audio signal output from the decoder 10 is input to the band dividing unit 14 and the band processing unit 45. The band dividing unit 14 divides the frequency band of the multi-channel audio signal output from the decoder 10, outputs the high frequency side to the beam processing unit 20, and outputs the low frequency side to the addition processing unit 32. The band processing unit 45 limits the predetermined band of the multi-channel audio signal output from the decoder 10 and outputs it to the virtual processing unit 40.

  FIG. 3 is a block diagram illustrating configurations of the band dividing unit 14, the band processing unit 45, and the addition processing unit 32.

  The band dividing unit 14 includes an HPF 14FL, an HPF 14FR, an HPF 14C, an HPF 14SL, and an HPF 14SR that respectively input digital audio signals of the FL channel, the FR channel, the C channel, the SL channel, and the SR channel. Further, the band dividing unit 14 includes LPF 15FL, LPF 15FR, LPF 15C, LPF 15SL, and LPF 15SR for inputting digital audio signals of FL channel, FR channel, C channel, SL channel, and SR channel, respectively.

  The HPF 14FL, HPF 14FR, HPF 14C, HPF 14SL, and HPF 14SR extract and output the high frequencies of the input audio signals of the respective channels. The cut-off frequency of HPF14FL, HPF14FR, HPF14C, HPF14SL, and HPF14SR is set to match the lower limit (for example, 400 Hz) of the reproduction frequency of the speaker units 21A to 21P. The output signals of HPF 14 FL, HPF 14 FR, HPF 14 C, HPF 14 SL, and HPF 14 SR are output to beam forming processing unit 20.

  The LPF 15FL, LPF 15FR, LPF 15C, LPF 15SL, and LPF 15SR extract and output the low frequency (for example, less than 400 Hz) of the input audio signal of each channel. The cut-off frequencies of the LPF 15FL, LPF 15FR, LPF 15C, LPF 15SL, and LPF 15SR correspond to the cut-off frequencies of the HPF 14FL, HPF 14FR, HPF 14C, HPF 14SL, and HPF 14SR (for example, 400 Hz).

  The output signals of the LPF 15FL, LPF 15C, and LPF 15SL are added by the adding unit 16L in the addition processing unit 32 to be an L channel audio signal. The L channel audio signal is subjected to gain adjustment by the gain adjustment unit 31L, and then input to the woofer 33L via the addition unit 32L.

  The output signals of the LPF 15FR, LPF 15C, and LPF 15SR are added by the adder 16R in the adder 32, and become an R channel audio signal. The R channel audio signal is subjected to gain adjustment by the gain adjustment unit 31R, and then input to the woofer 33R via the addition unit 32R.

  On the other hand, the band processing unit 45 includes HPF 40FL, HPF 40FR, HPF 40C, HPF 40SL, and HPF 40SR that respectively input digital audio signals of FL channel, FR channel, C channel, SL channel, and SR channel.

  The HPF 40FL, HPF 40FR, HPF 40C, HPF 40SL, and HPF 40SR extract and output the high frequencies of the input audio signals of the respective channels. The cutoff frequency of HPF 40FL, HPF 40FR, HPF 40C, HPF 40SL, and HPF 40SR is set to the same frequency (400 Hz) as that of each audio signal input to the beamization processing unit 20, for example.

  Next, the beamization processing unit 20 will be described. FIG. 4 is a block diagram illustrating a configuration of the beam processing unit 20. The beamization processing unit 20 includes a gain adjustment unit 18FL, a gain adjustment unit 18FR, a gain adjustment unit 18C, a gain adjustment unit 18SL, which input digital audio signals of FL channel, FR channel, C channel, SL channel, and SR channel, respectively. And a gain adjusting unit 18SR.

  The gain adjusting unit 18FL, the gain adjusting unit 18FR, the gain adjusting unit 18C, the gain adjusting unit 18SL, and the gain adjusting unit 18SR adjust the gain of the audio signal of each channel. The gain-adjusted audio signals of the respective channels are input to the directivity control unit 91FL, directivity control unit 91FR, directivity control unit 91C, directivity control unit 91SL, and directivity control unit 91SR, respectively. Directivity control unit 91FL, directivity control unit 91FR, directivity control unit 91C, directivity control unit 91SL, and directivity control unit 91SR distribute the audio signals of the respective channels to speaker units 21A to 21P. Audio signals for the distributed speaker units 21A to 21P are combined by the combining unit 92 and supplied to the speaker units 21A to 21P. At this time, the directivity controller 91FL, the directivity controller 91FR, the directivity controller 91C, the directivity controller 91SL, and the directivity controller 91SR adjust the delay amount of the audio signal supplied to each speaker unit.

  The sounds output from the speaker units 21A to 21P are strengthened with respect to each other at the same phase and are output as sound beams having directivity. For example, when sound is output from all the speakers at the same timing, a sound beam having directivity is output in front of the array speaker device 2. The directivity control unit 91FL, the directivity control unit 91FR, the directivity control unit 91C, the directivity control unit 91SL, and the directivity control unit 91SR change the delay amount added to each audio signal, thereby outputting the sound beam. The direction can be changed.

  In addition, the directivity control unit 91FL, the directivity control unit 91FR, the directivity control unit 91C, the directivity control unit 91SL, and the directivity control unit 91SR are configured so that the phase of each sound output from the speaker units 21A to 21P is a predetermined position. It is also possible to provide a delay amount so that the sound beam is focused and to form an audio beam that focuses at the predetermined position.

  The sound beam can reach the listening position directly from the array speaker device 2 or reflected on the wall of the room. For example, as shown in FIG. 5, the sound beam of the C channel audio signal can be output in the front direction so that the sound beam of the C channel can reach from the front of the listening position. Also, the sound beams of the FL channel audio signal and the FR channel audio signal are output in the left-right direction of the array speaker device 2 and reflected on the walls existing on the left and right of the listening position, respectively, from the left direction and the right direction of the listening position. Can be reached. In addition, the sound beams of the SL channel audio signal and the SR channel audio signal are output in the left-right direction and reflected twice on the wall existing on the left and right of the listening position and on the wall existing on the rear side, respectively. It can be reached from the right rear direction.

  Next, the virtual processing unit 40 will be described. FIG. 6 is a block diagram illustrating a configuration of the virtual processing unit 40. The virtual processing unit 40 includes a localization adding unit 42, a correcting unit 51, an adding unit 52L, an adding unit 52R, a delay processing unit 60L, and a delay processing unit 60R.

  The localization adding unit 42 performs processing for localizing the input FL channel, FR channel, C channel, SL channel, and SR channel audio signals as virtual sound sources at predetermined positions. In order to localize as a virtual sound source, a head-related transfer function (hereinafter referred to as HRTF) indicating a transfer function between a predetermined position and a listener's ear is used.

  The HRTF is an impulse response that expresses the volume, arrival time, frequency characteristics, and the like of the sound from the virtual speaker installed at a certain position to the left and right ears. The localization adding unit 42 can cause the listener to localize the virtual sound source by adding HRTF to the input audio signal of each channel and emitting sound from the woofer 33L or the woofer 33R.

  FIG. 7A is a block diagram illustrating a configuration of the localization adding unit 42. The localization adding unit 42 includes an FL filter 421L, an FR filter 422L, a C filter 423L, an SL filter 424L, and an SR filter 425L for convolving an HRTF impulse response with the audio signal of each channel, an FL filter 421R, an FR filter 422R, A C filter 423R, an SL filter 424R, and an SR filter 425R.

  For example, an audio signal of the FL channel is input to the FL filter 421L and the FL filter 421R. The FL filter 421L adds an HRTF of the path from the position of the virtual sound source VSFL (see FIG. 5) in front of the listener to the left ear to the FL channel audio signal. The FL filter 421R adds an HRTF of a path from the position of the virtual sound source VSFL to the right ear to the audio signal of the FL channel. Similarly, for each channel, an HRTF from the position of the virtual sound source around the listener to each ear is given.

  The adder 426L synthesizes the audio signals to which the HRTF has been added by the FL filter 421L, the FR filter 422L, the C filter 423L, the SL filter 424L, and the SR filter 425L, and outputs the synthesized audio signal to the correcting unit 51. The adder 426R synthesizes the audio signals to which the HRTF has been added by the FL filter 421R, the FR filter 422R, the C filter 423R, the SL filter 424R, and the SR filter 425R, and outputs the synthesized audio signal VR to the correcting unit 51.

  The correction unit 51 performs a crosstalk cancellation process. FIG. 7B is a block diagram illustrating a configuration of the correction unit 51. The correction unit 51 includes a direct correction unit 511L, a direct correction unit 511R, a cross correction unit 512L, and a cross correction unit 512R.

  The audio signal VL is input to the direct correction unit 511L and the cross correction unit 512L. The audio signal VR is input to the direct correction unit 511R and the cross correction unit 512R.

  The direct correction unit 511L performs a process of making the listener perceive that the sound output from the woofer 33L is emitted near the left ear. In the direct correction unit 511L, a filter coefficient is set such that the frequency characteristic of the sound output from the woofer 33L is flat at the position of the left ear. The direct correction unit 511L processes the input audio signal VL with the filter and outputs an audio signal VLD. In the direct correction unit 511R, a filter coefficient is set such that the frequency characteristic of the sound output from the woofer 33R is flat at the position of the right ear. The direct correction unit 511R processes the input audio signal VL with the filter and outputs the audio signal VRD.

  The cross correction unit 512L is set with a filter coefficient for providing a frequency characteristic of a sound that circulates from the woofer 33L to the right ear. The sound (VLC) that circulates from the woofer 33L to the right ear is reversed in phase by the synthesizer 52R and emitted from the woofer 33R, thereby suppressing the sound of the woofer 33L from being heard by the right ear. This makes the listener perceive that the sound emitted from the woofer 33R is emitted near the right ear.

  The cross correction unit 512R is set with a filter coefficient for imparting frequency characteristics of sound that circulates from the woofer 33R to the left ear. The sound (VRC) that circulates from the woofer 33R to the left ear is reversed in phase by the synthesizer 52L and emitted from the woofer 33L, thereby suppressing the sound of the woofer 33R from being heard by the left ear. This makes the listener perceive that the sound emitted from the woofer 33L is emitted near the left ear.

  The audio signal output from the synthesis unit 52L is input to the delay processing unit 60L. The audio signal delayed by a predetermined time by the delay processing unit 60L is input to the addition processing unit 32. The audio signal output from the synthesis unit 52R is input to the delay processing unit 60R. The audio signal delayed by a predetermined time by the delay processing unit 60R is input to the addition processing unit 32.

  The delay time by the delay processing unit 60L and the delay processing unit 60R is set longer than the longest delay time among the delay times given by the directivity control unit of the beamization processing unit 20, for example. Thereby, the sound that perceives the virtual sound source does not hinder the formation of the sound beam. Alternatively, a delay processing unit may be provided after the beam forming processing unit 20 so as to add a delay to the sound beam side so that the sound beam does not hinder the sound that localizes the virtual sound image.

  The gain of the audio signal output from the delay processing unit 60L is adjusted by the gain adjustment unit 61L of the addition processing unit 32. The audio signal whose gain has been adjusted by the gain adjusting unit 61L is added to the audio signal (the low-frequency component of the L channel of the original signal) output from the gain adjusting unit 31L in the adding unit 32L. The addition ratio of the low frequency component of the original signal and the output signal of the virtual processing unit 40 is changed by the gain adjusting unit 32L and the gain adjusting unit 61L.

  Similarly, the gain of the audio signal output from the delay processing unit 60R is adjusted by the gain adjusting unit 61R of the addition processing unit 32. The audio signal whose gain has been adjusted by the gain adjusting unit 61R is added to the audio signal (the low-frequency component of the R channel of the original signal) output from the gain adjusting unit 31R in the adding unit 32R. The addition ratio of the original signal and the output signal of the virtual processing unit 40 is changed by the gain adjusting unit 32R and the gain adjusting unit 61R.

  The array speaker device 2 adjusts the gains of the gain adjusting unit 18FL, the gain adjusting unit 18FR, the gain adjusting unit 18C, the gain adjusting unit 18SL, and the gain adjusting unit 18SR in the above-described beam forming processing unit 20 so as to be virtual. The level ratio of the output signal of the processing unit 40, the low frequency component of the original signal, and the sound beam can be adjusted.

  Next, the sound field generated by the array speaker device 2 will be described with reference to FIG. In FIG. 5, the solid arrow indicates the path of the sound beam output from the array speaker device 2. In FIG. 5, a white star indicates the position of the real sound source generated by the sound beam, and a black star indicates the position of the virtual sound source.

  In the example of FIG. 5, the array speaker device 2 outputs five sound beams. The C-channel audio signal is set to an audio beam that is focused at a position behind the array speaker device 2. Thus, the listener perceives that the sound source SC is in front of the listener.

  Similarly, in the audio signal of the FL channel, an audio beam focused on the position of the left front wall of the room R is set, and the listener perceives that the sound source SFL is on the left front wall of the listener. The audio signal of the FR channel is set with a sound beam that focuses on the position of the right front wall of the room R, and the listener perceives that the sound source SFR is on the right front wall of the listener. The audio signal of the SL channel is set with an audio beam focused on the position of the left rear wall of the room R, and the listener perceives that the sound source SSL is on the left rear wall of the listener. The audio signal of the SR channel is set with a sound beam that focuses on the position of the right rear wall of the room R, and the listener perceives that the sound source SSR is on the left rear wall of the listener.

  Further, the localization adding unit 42 sets the position of the virtual sound source at substantially the same position as the positions of the sound sources SFL, SFR, SC, SSL, and SSR. Therefore, as shown in FIG. 5, the listener perceives the virtual sound sources VSC, VSFL, VSFR, VSSL, and VSSR at substantially the same positions as the positions of the sound sources SFL, SFR, SC, SSL, and SSR. Note that the position of the virtual sound source need not be set at the same position as the focal point of the sound beam, and may be a predetermined direction. For example, the virtual sound source VSFL is set to 30 degrees left, the virtual sound source VSFR is set to 30 degrees right, the virtual sound source VSSL is set to 120 degrees left, the virtual sound source VSSR is set to 120 degrees right, and the like.

  Thereby, the array speaker device 2 can supplement the sense of localization by the sound beam with the virtual sound source, and can improve the sense of localization as compared with the case of using only the sound beam or the case of using only the virtual sound source. . In particular, the sound source SSL and the sound source SSR of the SL channel and the SR channel are generated when the sound beam is reflected twice on the wall, and thus there is a case where a clear localization feeling cannot be obtained as compared with the channel on the front side. However, the array speaker device 2 can supplement the sense of localization with the virtual sound source VSSL and the virtual sound source VSSR generated by the sound that directly reaches the ears of the listener by the woofer 33L and the woofer 33R, and the localization feeling of the SL channel and the SR channel can be compensated. There is no loss.

  In the array speaker device 2 according to the present embodiment, the band in which the filtering process using the head-related transfer function is performed is limited by the band processing unit 45. FIG. 8A is a conceptual diagram showing a band of an audio signal input to the speaker units 21A to 21P. FIG. 8B is a conceptual diagram showing a band of an audio signal input to the woofer 33L and the woofer 33R.

  As shown in FIG. 8A, audio signals in a band of frequency F1 (for example, 400 Hz) or higher are input to the speaker units 21A to 21P. The frequency F1 is set by the band dividing unit 14 according to the lower limit frequency of the speaker units 21A to 21P. Also, as shown in FIG. 8B, an audio signal in a band less than the frequency F1 (for example, 400 Hz) is input to the woofer 33L and the woofer 33R by the band dividing unit 14.

  The low band has low directivity, and the band in which sound having directivity such as an audio beam reaches the listener is mainly a middle and high band of several hundred Hz or more. Therefore, mid-high range audio signals are input to the speaker units 21A to 21P, and low frequency audio signals are input to the woofer 33L and the woofer 33R, so that the sound source is localized by the sound beam and the low frequency sound is reinforced. can do.

  The woofer 33L and the woofer 33R are also input with an audio signal that has been filtered by the head-related transfer function in the virtual processing unit 40. The audio signal has the same band as the audio signal input to the speaker units 21 </ b> A to 21 </ b> P because the band processing unit 45 passes only the band of the frequency F <b> 1 (for example, 400 Hz) or higher.

  Since the filter processing based on the head-related transfer function changes the frequency characteristic of the original audio signal, there is a change in sound quality. Therefore, if the filtering process using the head-related transfer function is performed in the entire band, the change in sound quality becomes conspicuous. However, in the array speaker device 2, since the band processing unit 45 passes only the band of the frequency F1 (for example, 400 Hz) or more and limits the band for performing the filter processing by the head related transfer function, the change in the sound quality is minimized. Can be suppressed. The frequency band that contributes to the sense of localization of the head-related transfer function is mainly about several kHz, and the sense of localization is not impaired even when a signal of less than several hundred Hz is not input.

  Therefore, the array speaker device 2 can supplement the sense of localization by the sound beam with the sense of localization by the virtual sound source, and can clearly localize the sound source while suppressing the change in sound quality. In addition, the frequency band of the audio signal after filtering by the head-related transfer function (virtual sound source in FIG. 8B) and the low frequency band divided from the original audio signal (original signal in FIG. 8B) And the virtual sound source and the low-frequency component of the original signal do not interfere with each other.

  The band dividing unit 14 sets the frequency F1 according to the lower limit frequency (for example, 400 Hz) of the speaker units 21A to 21P, but it is not always necessary to match the lower limit frequency. For example, you may make it divide | segment at a frequency higher than the said lower limit frequency.

  Further, the band processing unit 45 sets the lower limit frequency of the band through which the audio signal is passed to be the same as the frequency F1 divided by the band dividing unit 14, but it is not necessarily set to the same (or close) frequency. Absent. For example, as shown in FIG. 8C, the frequency F2 (for example, 1 kHz) may be higher than the frequency F1 (for example, 400 Hz).

  Next, FIG. 9 is a schematic diagram of an AV system 1A including the array speaker device 2A according to the first modification. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The AV system 1A includes an array speaker device 2A instead of the array speaker device 2 of FIG. Array speaker device 2A is different from array speaker device 2 in that it further includes a woofer 34L and a woofer 34R.

  FIG. 10 is a block diagram showing a configuration of the array speaker device 2A. The array speaker device 2A is different from the array speaker device 2 in that the addition processing unit 32 is not provided.

  The audio signal output from the virtual processing unit 40 is input to the woofer 33L and the woofer 33R. The audio signal output from the band dividing unit 14 is input to the woofer 34L and the woofer 34R.

  In this way, the frequency band of the audio signal after filtering by the head-related transfer function (virtual sound source in FIG. 8B) and the divided low frequency band of the original audio signal (original in FIG. 8B). Signal) may be input to different speaker units.

  Next, FIG. 11 is a block diagram showing a configuration of an array speaker device 2B according to Modification 2. The same components as those in the array speaker device 2 shown in FIG. The array speaker device 2B includes a band processing unit 45B and an addition processing unit 32B in place of the band processing unit 45 and the addition processing unit 32 of the array speaker device 2, and the band processing unit 45B sends an audio signal to the addition processing unit 32B. Output.

  FIG. 12 is a block diagram showing configurations of the band processing unit 45B and the addition processing unit 32B. Configurations common to the bandwidth processing unit 45 and the addition processing unit 32 illustrated in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.

  The band processing unit 45B includes LPF 41FL, LPF 41FR, LPF 41C, LPF 41SL, and LPF 41SR that respectively input digital audio signals of FL channel, FR channel, C channel, SL channel, and SR channel.

  The LPF 41FL, LPF 41FR, LPF 41C, LPF 41SL, and LPF 41SR extract and output the low frequencies of the input audio signals of the respective channels. The cut-off frequencies of LPF41FL, LPF41FR, LPF41C, LPF41SL, and LPF41SR correspond to the cut-off frequencies (for example, 400 Hz) of HPF40FL, HPF40FR, HPF40C, HPF40SL, and HPF40SR, respectively.

  The output signals of the LPF 41FL, LPF 41C, and LPF 41SL are added to the output signal of the virtual processing unit 40 (the output signal of the delay processing unit 60L) by the adding unit 17L of the addition processing unit 32B. The audio signal added by the adding unit 17L is input to the adding unit 32L after gain adjustment by the gain adjusting unit 61L.

  The output signals of the LPF 41FR, LPF 41C, and LPF 41SR are added to the output signal of the virtual processing unit 40 (the output signal of the delay processing unit 60R) by the addition unit 17R of the addition processing unit 32B. The audio signal added by the adding unit 17R is input to the adding unit 32R after gain adjustment by the gain adjusting unit 61R.

  Next, FIG. 13 is a diagram showing an array speaker device 2C according to Modification 3. The components common to the array speaker device 2 are denoted by the same reference numerals, and description thereof is omitted.

  The array speaker device 2 </ b> C further includes a subwoofer 3. The subwoofer 3 receives a low frequency (for example, less than 100 Hz) audio signal from the band dividing unit 140C. FIG. 14 is a block diagram illustrating a configuration of the band dividing unit 140C. The same components as those of the band dividing unit 14 are denoted by the same reference numerals and description thereof is omitted.

  The band dividing unit 140C includes an adding unit 160, an adding unit 170, an HPF 150L, an HPF 152R, an LPF 151L, an LPF 153R, and an adding unit 700.

  Adder 160 adds the output signals of LPF 15FL, LPF 15C, and LPF 15SL. Adder 170 adds the output signals of LPF 15FR, LPF 15C, and LPF 15SR. The output signal of the adding unit 160 is input to the HPF 150L and the LPF 151L. The output signal of the adding unit 170 is input to the HPF 152R and the LPF 153R.

  The HPF 150L extracts and outputs the high range of the input audio signal. The LPF 151L extracts and outputs a low frequency range of the input audio signal. The cutoff frequencies of the HPF 150L and the LPF 151L correspond to the crossover frequency (for example, 100 Hz) between the woofer 33L and the subwoofer 3. The crossover frequency may be changed by the listener.

  Similarly, the HPF 152R extracts and outputs the high range of the input audio signal. The LPF 153R extracts and outputs the low frequency range of the input audio signal. The cut-off frequencies of the HP 152R and the LPF 153R correspond to the crossover frequency (for example, 100 Hz) between the woofer 33R and the subwoofer 3. The crossover frequency may be changed by the listener.

  FIG. 15A is a conceptual diagram showing the band of the audio signal input to the speaker units 21A to 21P, and FIG. 15B shows the band of the audio signal input to the woofer 33L and the woofer 33R. It is a conceptual diagram. FIG. 15C is a conceptual diagram showing a band of an audio signal input to the subwoofer 3.

  In the array speaker device 2 </ b> C, as shown in FIG. 15C, an audio signal in a band less than the frequency F <b> 3 (for example, 100 Hz) is input to the subwoofer 3. Further, as shown in FIG. 15B, an audio signal in a band not lower than the frequency F3 (for example, 100 Hz) and lower than the frequency F1 (for example, 400 Hz) is input to the woofer 33L and the woofer 33R by the band dividing unit 140C.

  As described above, the array speaker device 2 </ b> C further includes the subwoofer 3, and is a mode in which the sound on the lower frequency side than the frequency that can be output by the woofer 33 </ b> L and the woofer 33 </ b> R is reinforced. Also in this case, the band processing unit 45 sets the lower limit frequency (frequency F1 = 400 Hz in the example of FIG. 15) of the band to be passed to the virtual processing unit 40 to be higher than the upper limit frequency of the subwoofer (F3 = 100 Hz in the example of FIG. 15). Since it is set high, the band of the sound output from the subwoofer and the sound after filtering does not overlap. Therefore, the sound output from the subwoofer 3 and the sound of the virtual sound source do not interfere with each other.

  Although not shown, even in the aspect including the subwoofer 3, the low-frequency audio signal is extracted by the band processing unit 45B and added at the subsequent stage of the virtual processing unit 40 as shown in FIGS. You may do it.

  Next, FIG. 16A is a diagram showing an array speaker device 2D according to Modification 4. The components common to the array speaker device 2 are denoted by the same reference numerals, and description thereof is omitted.

  The array speaker device 2D is different from the array speaker device 2 in that sounds output from the woofer 33L and the woofer 33R are output from the speaker unit 21A and the speaker unit 21P, respectively.

  The array speaker device 2D outputs sound that makes a virtual sound source perceived from the speaker units 21A and 21P at both ends of the speaker units 21A to 21P.

  The speaker unit 21 </ b> A and the speaker unit 21 </ b> P are the speaker units arranged at the extreme ends of the array speaker, and are arranged on the left and right sides as viewed from the listener. Therefore, the speaker unit 21A and the speaker unit 21P are suitable for outputting the sound of the L channel and the R channel, respectively, and are suitable as the speaker unit for outputting the sound that makes the virtual sound source be perceived.

  Also in the array speaker device 2D, since the band of the audio signal that is filtered by the head-related transfer function is limited in the virtual processing unit 40, it is possible to supplement the sense of localization by the sound beam with the sense of localization by the virtual sound source, Sound source can be clearly localized while suppressing changes in sound quality.

  Further, the array speaker device 2 does not have to include all the speaker units 21A to 21P, the woofer 33L, and the woofer 33R in one housing. For example, as in a speaker set 2E shown in FIG. 16B, each speaker unit may be provided in an individual casing, and the casings may be arranged side by side.

  Further, the actual sound source is not limited to the example of localization using a sound beam. For example, as shown in FIG. 17, it can be realized by surround speakers (speaker unit 21FL, speaker unit 21FR, speaker unit 21C, speaker unit 21SL, and speaker unit 21SR) installed around the listening position.

DESCRIPTION OF SYMBOLS 1 ... AV system 2 ... Array speaker apparatus 4 ... Television 10 ... Decoder 11 ... Input part 14 ... Band division | segmentation part 20 ... Beam formation process part Speaker unit 21A-21P ... Speaker unit 32 ... Addition process part 33L, 33R ... Woofer 40 ... Virtual processing unit 42 ... Localization adding unit 45 ... Band processing unit

Claims (6)

A first sound emitting unit for outputting a sound based on the input audio signal;
A localization adding unit that performs filtering on the input audio signal based on the head-related transfer function;
A second sound emitting unit for outputting a sound based on the audio signal filtered by the localization adding unit;
A band processing unit for limiting a frequency band of an audio signal input to the localization adding unit;
A speaker device comprising: The speaker device according to claim 1,
Further equipped with a subwoofer,
The speaker device according to claim 1, wherein the band processing unit has a lower limit frequency of a band through which an audio signal passes, which is higher than an upper limit frequency of the subwoofer. The second sound emitting unit includes a speaker unit having a lower limit frequency lower than the lower limit frequency of the first sound emitting unit,
The speaker device according to claim 1 or 2, wherein an audio signal lower than a lower limit frequency of the first sound emitting unit is input to the second sound emitting unit. An input section for inputting an audio signal;
The frequency band of the audio signal input to the input unit is divided, the high frequency audio signal is input to the first sound emitting unit, and the low frequency audio signal is input to the second sound emitting unit. The speaker device according to claim 1, further comprising a dividing unit.   5. The speaker device according to claim 4, wherein the band processing unit has a lower limit frequency of a band through which an audio signal passes, which is the same as or close to a frequency divided by the band dividing unit. The first sound emitting unit is a speaker array in which a plurality of speakers are arranged,
6. The directivity control unit according to claim 1, further comprising: a directivity control unit that outputs an audio beam to the first sound emitting unit by delaying an input audio signal and distributing the audio signal to the plurality of speakers. Speaker device.

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