Acoustic system, electronic musical instrument, and acoustic processing method

Abstract

To radiate a reverberant sound that is sufficiently perceived as a sense of depth or expansion while suppressing the delay of direct sound.SOLUTION: An electronic musical instrument consists of: a keyboard that accepts a playing operation by a user; a sound source unit 41 that generates acoustic signals S(SL,SR) in response to the operation on the keyboard; a reverberation generator unit 42 that generates reverberation signals X(XL,XR) representing waveforms of reverberation sound corresponding to the acoustic signals S; a signal processing unit 50 that generates reverberation signals Z(ZL,ZR) by performing binaural processing and transaural processing on the reverberation signals X; and a first speaker 31 that radiates sounds corresponding to the acoustic signals S; and a dipole type second speaker 32 that radiates the reverberation sound corresponding to the reverberation signal Z.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a technique for emitting sound in response to an acoustic signal. [Background technology]

[0002] Various techniques have been proposed for controlling the sound image perceived by a listener. For example, Patent Document 1 discloses a technique for controlling the position of a sound image by reproducing an acoustic signal generated by sound image localization processing using a stereo dipole speaker. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-333297 Summary of the Invention [Problem to be solved by the invention]

[0004] Assume a case in which direct sound that reaches a listener directly from a sound source and reverberant sound corresponding to the direct sound are reproduced. When sound image localization processing is performed on an acoustic signal including both direct sound and reverberant sound, the radiation of the direct sound and reverberant sound is delayed due to the sound image localization processing. There is a problem in that the delay of the direct sound is more easily perceived by the listener than the delay of the reverberant sound. In consideration of the above circumstances, one aspect of the present disclosure aims to radiate reverberant sound that provides a sufficient sense of depth or spaciousness while suppressing the delay of the direct sound. [Means for solving the problem]

[0005] In order to solve the above problems, an acoustic system according to one embodiment of the present disclosure includes a signal acquisition unit that acquires an acoustic signal and a first reverberation signal that represents the waveform of a reverberation sound corresponding to the acoustic signal, a signal processing unit that generates a second reverberation signal by performing binaural processing and transaural processing on the first reverberation signal, a first speaker that radiates sound corresponding to the acoustic signal, and a dipole-type second speaker that radiates reverberation sound corresponding to the second reverberation signal.

[0006] An electronic musical instrument according to one embodiment of the present disclosure includes an operation receiving unit that receives performance operations from a user, a signal generating unit that generates an acoustic signal in response to the operation received by the operation receiving unit, a reverberation generating unit that generates a first reverberation signal representing the waveform of a reverberation sound corresponding to the acoustic signal, a signal processing unit that generates a second reverberation signal by performing binaural processing and transaural processing on the first reverberation signal, a first speaker that emits sound in response to the acoustic signal, and a dipole-type second speaker that emits reverberation sound in response to the second reverberation signal. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a front view of an electronic musical instrument. [Figure 2] FIG. 2 is a block diagram illustrating an example of the electrical configuration of the electronic musical instrument. [Figure 3] FIG. 1 is a block diagram illustrating an example of the functional configuration of an electronic musical instrument. [Figure 4] FIG. 10 is an explanatory diagram of binaural processing. [Figure 5] FIG. 1 is an explanatory diagram of transaural processing. [Figure 6] 10 is a flowchart of a process executed by a control device. [Figure 7] FIG. 10 is a front view of the electronic musical instrument according to the second embodiment. [Figure 8] FIG. 10 is a front view of an electronic musical instrument according to a third embodiment. [Figure 9] FIG. 10 is a front view of an electronic musical instrument according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A: First embodiment 1 is a front view of an electronic musical instrument 100 according to a first embodiment. The electronic musical instrument 100 is a keyboard instrument that includes a keyboard 11 and a housing 12. The electronic musical instrument 100 is an example of an "acoustic system."

[0009] The keyboard 11 is composed of a plurality of keys 13 (white keys and black keys) corresponding to different pitches. The plurality of keys 13 are arranged along the X-axis. A user plays a desired piece of music by operating each of the plurality of keys 13 in sequence. In other words, the keyboard 11 is an operation receiving unit that receives performance operations by the user. The direction of the X-axis is the longitudinal direction of the keyboard 11, and corresponds to the left-right direction of a user playing the electronic musical instrument 100.

[0010] The housing 12 is a structure that supports the keyboard 11. Specifically, the housing 12 includes a right arm 121, a left arm 122, a shelf 123 (mouth bar), an upper front panel 124, a lower front panel 125, and a top panel 126 (roof). The shelf 123 is a plate-like member that supports the keyboard 11 from below in the vertical direction. The keyboard 11 and the shelf 123 are installed between the right arm 121 and the left arm 122. The upper front panel 124 and the lower front panel 125 are flat plate members that form the front surface of the housing 12 and are installed parallel to each other in the vertical direction. The upper front panel 124 is located above the keyboard 11, and the lower front panel 125 is located below the keyboard 11. The top panel 126 is a flat plate member that forms the top surface of the housing 12. A gap is formed between the upper front panel 124 and the top panel 126 along the X-axis.

[0011] In the following description, a reference plane C is assumed. The reference plane C is a plane of symmetry of the electronic musical instrument 100. In other words, the reference plane C is an imaginary plane that is perpendicular to the X-axis and passes through the midpoint of the keyboard 11 in the direction of the X-axis.

[0012] 2 is a block diagram illustrating an example of the electrical configuration of the electronic musical instrument 100. The electronic musical instrument 100 includes a control device 21, a storage device 22, a detection device 23, and a playback device 24. The control device 21 and the storage device 22 form a control system 20 that controls the operation of the electronic musical instrument 100. In the first embodiment, the control system 20 is mounted on the electronic musical instrument 100, but the control system 20 may also be configured separately from the electronic musical instrument 100. For example, the control system 20 may be realized by an information device such as a smartphone or a tablet terminal.

[0013] The control device 21 is one or more processors that control the operation of the electronic musical instrument 100. Specifically, the control device 21 is configured by one or more types of processors, such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an SPU (Sound Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit).

[0014] The storage device 22 is one or more memories that store programs executed by the control device 21 and various data used by the control device 21. For example, a well-known recording medium such as a semiconductor recording medium or a magnetic recording medium, or a combination of multiple types of recording media, is used as the storage device 22. Note that, for example, a portable recording medium that is detachable from the electronic musical instrument 100, or a recording medium that the control device 21 can access via a communication network (e.g., cloud storage) may also be used as the storage device 22.

[0015] The detection device 23 is a sensor unit that detects an operation by a user on the keyboard 11. Specifically, the detection device 23 outputs performance information E that specifies the key 13 that the user has operated among the multiple keys 13 that make up the keyboard 11. The performance information E is, for example, MIDI (Musical Instrument Digital Interface) event data that specifies the number corresponding to the key 13 that the user has operated.

[0016] The playback device 24 emits sounds in response to user operations on the keyboard 11. Fig. 3 is a block diagram illustrating an example of the functional configuration of the electronic musical instrument 100. The playback device 24 includes a first speaker 31, a second speaker 32, and headphones 33. The first speaker 31 and the second speaker 32 are installed in the housing 12. The headphones 33 are connected to the electronic musical instrument 100 by wire or wirelessly.

[0017] The first speaker 31 is a stereo speaker including a first left channel speaker 31L and a first right channel speaker 31R. As illustrated in FIG. 1 , the first speaker 31 is installed on the lower front panel 125 of the housing 12. Specifically, the first left channel speaker 31L and the first right channel speaker 31R are installed on the lower front panel 125 with a distance D1 between them in the X-axis direction. Specifically, when viewed from the front of the electronic musical instrument 100, the first left channel speaker 31L is located on the left side of a reference plane C, and the first right channel speaker 31R is located on the right side of the reference plane C. The distance D1 is the distance between the central axis of the diaphragm of the first left channel speaker 31L and the central axis of the diaphragm of the first right channel speaker 31R. The reference plane C may be understood to be an imaginary plane equidistant from the central axis of the diaphragm of the first left channel speaker 31L and the central axis of the diaphragm of the first right channel speaker 31R.

[0018] 3 is a dipole stereo speaker (i.e., a stereo dipole speaker) including a second left channel speaker 32L and a second right channel speaker 32R. That is, the second left channel speaker 32L and the second right channel speaker 32R arranged close to each other can allow the user to perceive a three-dimensional sound field. The second left channel speaker 32L and the second right channel speaker 32R have smaller diameters than the first left channel speaker 31L and the first right channel speaker 31R.

[0019] As illustrated in FIG. 1 , the second speaker 32 is installed along the upper vertical edge of the upper front panel 124. Specifically, the second speaker 32 is installed in the gap between the upper front panel 124 and the top panel 126 of the housing 12. The second left channel speaker 32L and the second right channel speaker 32R are installed with a distance D2 between them in the X-axis direction. That is, when viewed from the front of the electronic musical instrument 100, the second left channel speaker 32L is located on the left side of the reference plane C, and the second right channel speaker 32R is located on the right side of the reference plane C. The distance D2 is the distance between the central axis of the diaphragm of the second left channel speaker 32L and the central axis of the diaphragm of the second right channel speaker 32R. As can be understood from the above explanation, the first speaker 31 and the second speaker 32 are located on opposite sides of the keyboard 11. The reference plane C may be an imaginary plane equidistant from the central axis of the diaphragm of the second left channel speaker 32L and the central axis of the diaphragm of the second right channel speaker 32R.

[0020] As can be seen from FIG. 1, the distance D1 between the first left channel speaker 31L and the first right channel speaker 31R is greater than the distance D2 between the second left channel speaker 32L and the second right channel speaker 32R (D1>D2).

[0021] The headphones 33 are stereo headphones including a left-ear speaker 33L and a right-ear speaker 33R, and are worn on the user's head. The left-ear speaker 33L and the right-ear speaker 33R are connected to each other via a headband 331. The left-ear speaker 33L is worn on the user's left ear, and the right-ear speaker 33R is worn on the user's right ear.

[0022] 3, the control device 21 functions as an acoustic processing unit 200 by executing a program stored in the storage device 22. The acoustic processing unit 200 generates an acoustic signal S (SL, SR), a reverberation signal Z (ZL, ZR), and a reproduction signal W (WL, WR). Specifically, the acoustic processing unit 200 includes a signal acquisition unit 40, a signal processing unit 50, and a reproduction processing unit 60.

[0023] The acoustic signal S is a two-channel stereo signal consisting of a left-channel acoustic signal SL and a right-channel acoustic signal SR. The acoustic signal S is supplied to a first speaker 31. Specifically, the left-channel acoustic signal SL is supplied to a first left-channel speaker 31L, and the right-channel acoustic signal SR is supplied to a first right-channel speaker 31R. For convenience, a D / A converter that converts the acoustic signal S from digital to analog and an amplifier that amplifies the acoustic signal S are not shown in the figure.

[0024] The reverberation signal Z is a two-channel stereo signal consisting of a left-channel reverberation signal ZL and a right-channel reverberation signal ZR. The reverberation signal Z is supplied to the second speaker 32. Specifically, the left-channel reverberation signal ZL is supplied to the second left-channel speaker 32L, and the right-channel reverberation signal ZR is supplied to the second right-channel speaker 32R. For convenience, a D / A converter that converts the reverberation signal Z from digital to analog and an amplifier that amplifies the reverberation signal Z are not shown in the figure. The reverberation signal Z is an example of a "second reverberation signal."

[0025] The playback signal W is a two-channel stereo signal consisting of a left-channel playback signal WL and a right-channel playback signal WR. The playback signal W is supplied to headphones 33. Specifically, the left-channel playback signal WL is supplied to a left-ear speaker 33L, and the right-channel playback signal WR is supplied to a right-ear speaker 33R. For convenience, a D / A converter that converts the playback signal W from digital to analog and an amplifier that amplifies the playback signal W are not shown in the figure.

[0026] The signal acquisition unit 40 acquires an acoustic signal S (SL, SR) and a reverberation signal X (XL, XR). The reverberation signal X is a two-channel stereo signal consisting of a left-channel reverberation signal XL and a right-channel reverberation signal XR.

[0027] The signal acquisition unit 40 of the first embodiment includes a sound source unit 41 and a reverberation generation unit 42 (42L, 42R). The sound source unit 41 generates an audio signal S (SL, SR) in response to a user's operation on the keyboard 11. Specifically, the sound source unit 41 is a MIDI sound source that generates an audio signal S in response to performance information E output by the detection device 23. That is, the audio signal S is a signal representing the waveform of a sound having a pitch corresponding to one or more keys 13 operated by the user. The sound source unit 41 is, for example, a software sound source realized by the control device 21 executing a sound source program, or a hardware sound source realized by an electronic circuit dedicated to generating the audio signal S. The audio signal S represents the waveform of a direct sound (dry sound) that does not include reverberation. The sound source unit 41 is an example of a "signal generation unit."

[0028] The acoustic signal S generated by the sound source unit 41 is supplied to the first speaker 31. The first speaker 31 emits a direct sound corresponding to the acoustic signal S. Specifically, the first left channel speaker 31L emits a direct sound corresponding to the acoustic signal SL, and the first right channel speaker 31R emits a direct sound corresponding to the acoustic signal SR.

[0029] The reverberation generation unit 42L and the reverberation generation unit 42R generate reverberation signals X(XL, XR) that represent the waveform of reverberant sound corresponding to the sound signal S. Specifically, the reverberation generation unit 42L generates the reverberation signal XL by performing reverberation processing on the sound signal SL. The reverberation generation unit 42R generates the reverberation signal XR by performing reverberation processing on the sound signal SR. The reverberation processing is a computational process that simulates sound reflection in a virtual acoustic space. The reverberation signal X(XL, XR) represents the waveform of reverberant sound (wet sound) that does not include direct sound. The reverberation signal X is an example of a "first reverberation signal."

[0030] The signal processing unit 50 generates a reverberation signal Z(ZL, ZR) by performing signal processing on the reverberation signal X(XL, XR). The signal processing unit 50 of the first embodiment includes a first processing unit 51 and a second processing unit 52.

[0031] The first processing unit 51 generates an intermediate signal Y(YL, YR) by performing binaural processing on the reverberation signal X. The intermediate signal Y is a two-channel stereo signal consisting of a left-channel intermediate signal YL and a right-channel intermediate signal YR.

[0032] Binaural processing is signal processing that localizes a sound image at a specific position by applying a head-related transfer characteristic F (F11, F12, F21, F22) to a reverberation signal X. Specifically, the first processing unit 51 is composed of four characteristic applying units 511 (511a, 511b, 511c, 511d) and two adders 512 (512L, 512R). Each characteristic applying unit 511 performs a convolution operation to apply a head-related transfer characteristic F to the reverberation signal X.

[0033] 4 is an explanatory diagram of binaural processing. Binaural processing is signal processing that simulates the behavior of sound emitted from a virtual left channel speaker 38L and a virtual right channel speaker 38R as it travels to both ears of a listener U. The head-related transfer characteristic F11 is the transfer characteristic from the left channel speaker 38L to the left ear canal of the listener U (i.e., the player of the electronic musical instrument 100). The head-related transfer characteristic F12 is the transfer characteristic from the left channel speaker 38L to the right ear canal of the listener U. The head-related transfer characteristic F21 is the transfer characteristic from the right channel speaker 38R to the left ear canal of the listener U. The head-related transfer characteristic F22 is the transfer characteristic from the right channel speaker 38R to the right ear canal of the listener U.

[0034] 3 generates a signal y11 by applying a head-related transfer characteristic F11 to the reverberation signal XL. The characteristic applying unit 511b generates a signal y12 by applying a head-related transfer characteristic F12 to the reverberation signal XL. The characteristic applying unit 511c generates a signal y21 by applying a head-related transfer characteristic F21 to the reverberation signal XR. The characteristic applying unit 511d generates a signal y22 by applying a head-related transfer characteristic F22 to the reverberation signal XR.

[0035] The adder 512L generates an intermediate signal YL by adding the signal y11 and the signal y21. That is, the propagation of sound from the left channel speaker 38L and the right channel speaker 38R to the left ear of the listener U is simulated. The adder 512R generates an intermediate signal YR by adding the signal y12 and the signal y22. That is, the propagation of sound from the left channel speaker 38L and the right channel speaker 38R to the right ear of the listener U is simulated.

[0036] The head-related transfer characteristics F (F11, F12, F21, F22) are set so that when the intermediate signal Y is played through the headphones 33, virtual speakers (hereinafter referred to as "virtual speakers") that radiate the reverberation sound represented by the intermediate signal Y are located at positions away from the electronic musical instrument 100. Specifically, as illustrated in FIG. 1 , the head-related transfer characteristics F are set so that the virtual speakers (first virtual speaker ML, second virtual speaker MR) of the reverberation sound perceived by the user are located at the upper left and upper right of the electronic musical instrument 100. The first virtual speaker ML and the second virtual speaker MR are located on opposite sides of the reference plane C. The distance Dv between the first virtual speaker ML and the second virtual speaker MR is greater than the distance D2 between the second left channel speaker 32L and the second right channel speaker 32R. Furthermore, the distance Dv between the first virtual speaker ML and the second virtual speaker MR is greater than the distance D1 between the first left channel speaker 31L and the first right channel speaker 31R.

[0037] The second processing unit 52 in FIG. 3 generates a reverberation signal Z(ZL, ZR) by performing transaural processing on the intermediate signal Y(YL, YR). The transaural processing is signal processing for crosstalk cancellation. Specifically, the transaural processing is processing for adjusting the intermediate signal Y so that sound corresponding to the intermediate signal YL does not reach the user's right ear (i.e., reaches only the left ear) and sound corresponding to the intermediate signal YR does not reach the user's left ear (i.e., reaches only the right ear). The transaural processing can also be expressed as processing for adjusting the reverberation sound represented by the intermediate signal Y so that the characteristics of the reverberation sound reaching the user from the second speaker 32 approach the characteristics of the reverberation sound reproduced by the headphones 33. Specifically, the second processing unit 52 is composed of four characteristic applying units 521 (521a, 521b, 521c, 521d) and two adders 522 (522L, 522R). Each characteristic applying unit 521 performs a convolution operation to apply a transfer characteristic H (H11, H12, H21, H22) to the intermediate signal Y.

[0038] FIG. 5 is an explanatory diagram of transaural processing. The characteristic assigning unit 521a generates a signal z11 by assigning a transfer characteristic H11 to the intermediate signal YL. The characteristic assigning unit 521b generates a signal z12 by assigning a transfer characteristic H12 to the intermediate signal YL. The characteristic assigning unit 521c generates a signal z21 by assigning a transfer characteristic H21 to the intermediate signal YR. The characteristic assigning unit 521d generates a signal z22 by assigning a transfer characteristic H22 to the intermediate signal YR. The adder 522L generates a reverberation signal ZL by adding the signal z11 and the signal z21. The adder 522R generates a reverberation signal ZR by adding the signal z12 and the signal z22. As can be understood from the above explanation, the process of generating the reverberation signal Z by the second processing unit 52 is expressed by the following mathematical formula (1).

number

[0039] 5 illustrates transfer characteristics G (G11, G12, G21, G22). The transfer characteristic G11 is the transfer characteristic from the second left channel speaker 32L to the left ear of the listener U, and the transfer characteristic G12 is the transfer characteristic from the second left channel speaker 32L to the right ear of the listener U. Furthermore, the transfer characteristic G21 is the transfer characteristic from the second right channel speaker 32R to the left ear of the listener U, and the transfer characteristic G22 is the transfer characteristic from the second right channel speaker 32R to the right ear of the listener U. Therefore, the sound component QL reaching the left ear of the listener U from the second speaker 32 and the sound component QR reaching the right ear of the listener U from the second speaker 32 are expressed by the following equation (2). The sound reaching the right ear of the listener U from the second left channel speaker 32L and the sound reaching the left ear of the listener U from the second right channel speaker 32R is crosstalk.

number

[0040] The following formula (3) is derived from formulas (1) and (2).

number

[0041] On the other hand, if we assume that crosstalk is removed by convolution of the transfer characteristic H, the following formula (4) is derived. Note that the symbol e -jωt denotes the delay of the sound component Q(QL,QR) relative to the intermediate signal Y.

number

[0042] From the formulas (3) and (4), the following formula (5) expressing the condition of the transfer characteristic H is derived.

number

[0043] As can be seen from equation (5), the transfer characteristic H (H11, H12, H21, H22) applied to generate the reverberation signal Z (ZL, ZR) corresponds to the inverse characteristic of the transfer characteristic G from the second speaker 32 to both ears of the user. Specifically, the transfer characteristic G assumed in the sound field from the second speaker 32 to the user is identified experimentally or experimentally, and the transfer characteristic H, which is the inverse characteristic of the transfer characteristic G, is set. The second processing unit 52 generates the reverberation signal Z by transaural processing using the transfer characteristic H described above.

[0044] As described above, the signal processing unit 50 generates the reverberation signal Z by performing binaural processing and transaural processing on the reverberation signal X. Therefore, the reverberation signal Z is delayed with respect to the sound signal S by the time required for the binaural processing and transaural processing.

[0045] As illustrated in FIG. 3 , the reverberation signal Z generated by the signal processing unit 50 (second processing unit 52) ​​is supplied to the second speaker 32. The second speaker 32 emits reverberation sound corresponding to the reverberation signal Z. Specifically, the second left channel speaker 32L emits reverberation sound corresponding to the reverberation signal ZL, and the second right channel speaker 32R emits reverberation sound corresponding to the reverberation signal ZR. As described above, the direct sound represented by the acoustic signal S is emitted from the first speaker 31, and the reverberation sound corresponding to the acoustic signal S is emitted from the dipole second speaker 32. As described above, the signal processing unit 50 performs transaural processing in addition to binaural processing, thereby reducing the transfer characteristic G from the second speaker 32 to the user. Therefore, the user can clearly perceive the first virtual speaker ML and the second virtual speaker MR generated by the binaural processing.

[0046] As described above, according to the first embodiment, a direct sound corresponding to the acoustic signal S is emitted from the first speaker 31. Meanwhile, a reverberation signal Z is generated by performing binaural processing and transaural processing on a reverberation signal X representing the waveform of a reverberation sound corresponding to the acoustic signal S. The reverberation sound corresponding to the reverberation signal Z is emitted from the dipole-type second speaker 32. Therefore, compared to a configuration in which binaural processing and transaural processing are performed on a signal including both a direct sound and a reverberation sound, it is possible to emit a reverberation sound that provides a sufficient sense of depth or spaciousness to the user while suppressing the delay of the direct sound. Since the delay of the reverberation sound is hardly perceptible, the delay of the reverberation sound caused by the signal processing by the signal processing unit 50 does not pose a particular problem.

[0047] In the first embodiment, musical sounds corresponding to the user's operation of the keyboard 11 are emitted as direct sounds from the first speaker 31. In a configuration in which the delay of the direct sounds is large, the generation of musical sounds is delayed in response to the user's operation of the keyboard 11, which may hinder the user's smooth and natural performance. Considering the above circumstances, the present disclosure, which can suppress the delay of direct sounds, is particularly suitable for use in the electronic musical instrument 100 as exemplified in the first embodiment.

[0048] Furthermore, in a configuration in which binaural processing and transaural processing are performed on a signal containing both direct sound and reverberant sound, the timbre of the direct sound may change before and after the processing. In the first embodiment, binaural processing and transaural processing are performed on the reverberant signal X, which represents the waveform of the reverberant sound corresponding to the acoustic signal S. Therefore, no change in timbre due to the binaural processing or transaural processing occurs in the direct sound emitted from the first speaker 31. Note that the change in timbre of the reverberant sound is difficult to perceive. Therefore, the change in timbre of the reverberant sound due to the signal processing by the signal processing unit 50 does not pose a particular problem.

[0049] As described above, the signal processing unit 50 performs binaural processing and transaural processing so that the virtual speaker of the reverberation sound corresponding to the reverberation signal Z is located at a distance from the acoustic system. That is, as described above, the binaural processing and transaural processing are performed so that the first virtual speaker ML and the second virtual speaker MR of the reverberation sound corresponding to the reverberation signal Z are located on opposite sides of the reference plane C. Therefore, the user can sufficiently perceive a sense of depth or spaciousness for the reverberation sound radiated from the second speaker 32. Furthermore, in the first embodiment, the distance D1 between the first left channel speaker 31L and the first right channel speaker 31R is wider than the distance D2 between the second left channel speaker 32L and the second right channel speaker 32R. Therefore, the user can sufficiently perceive a sense of depth or spaciousness for the direct sound corresponding to the acoustic signal S.

[0050] In the first embodiment, the first left channel speaker 31L and the second left channel speaker 32L are located on the left side of the reference plane C, and the first right channel speaker 31R and the second right channel speaker 32R are located on the right side of the reference plane C. Therefore, the user can sufficiently perceive a sense of depth or spaciousness for both the direct sound corresponding to the acoustic signal S and the reverberation sound corresponding to the reverberation signal Z.

[0051] The positions of the first virtual speaker ML and the second virtual speaker MR are not limited to the above examples. For example, the virtual speakers (first virtual speaker ML, second virtual speaker MR) may be located at the lower left and lower right of the electronic musical instrument 100. A configuration in which the virtual speakers are located at the lower left and lower right of the electronic musical instrument 100 allows the user to perceive a sense of depth or spaciousness of reverberant sounds even in an environment in which the electronic musical instrument 100 is placed on a floor with high sound absorption properties, such as carpet.

[0052] The reproduction processing unit 60 in FIG. 3 generates a reproduction signal W(WL, WR) to be supplied to the headphones 33. Because the sound radiated from the headphones 33 reaches both ears of the user directly, the transfer characteristic G is not imparted to the radiated sound reaching both ears of the user. Therefore, transaural processing is not required to generate the reproduction signal W. Therefore, the reproduction processing unit 60 generates the reproduction signal W in accordance with the acoustic signal S and the intermediate signal Y. As described above, the intermediate signal Y is a signal before transaural processing is performed. The reproduction processing unit 60 in the first embodiment includes a delay unit 61 and an adder unit 62.

[0053] The delay unit 61 delays the intermediate signal Y. Specifically, the delay unit 61 generates an intermediate signal wL by delaying the intermediate signal YL by a delay amount D, and generates an intermediate signal wR by delaying the intermediate signal YR by the delay amount D. The delay amount D corresponds to the processing time required for transaural processing by the second processing unit 52.

[0054] The adder 62 generates a reproduction signal W by adding the delayed intermediate signal w(wL, wR) and the acoustic signal S(SL, SR). Specifically, the adder 62 generates a reproduction signal WL for the left channel by adding the delayed intermediate signal wL and the acoustic signal SL, and generates a reproduction signal WR for the right channel by adding the delayed intermediate signal wR and the acoustic signal SR. Therefore, the reproduction signal W is a signal that represents the waveform of a mixture of direct sound and reverberant sound.

[0055] The adder 62 outputs the playback signal W to the headphones 33. The headphones 33 emit direct sound and reverberant sound corresponding to the playback signal W. Specifically, the left-ear speaker 33L emits direct sound and reverberant sound corresponding to the playback signal WL, and the right-ear speaker 33R emits direct sound and reverberant sound corresponding to the playback signal WR. Therefore, the user can perceive virtual speakers of reverberant sound generated by binaural processing through the headphones 33. Specifically, while listening to the direct sound represented by the acoustic signal S, the user of the headphones 33 perceives a first virtual speaker ML and a second virtual speaker MR of reverberant sound corresponding to the reverberant signal Z on opposite sides of the reference plane C. Therefore, the user can fully perceive the sense of depth or spaciousness of the reverberant sound.

[0056] In the first embodiment, the reproduction signal W is generated by adding the intermediate signal w delayed by the delay unit 61 to the acoustic signal S. Therefore, the delay of the reverberation sound relative to the direct sound can be made closer to each other between the sound radiated by the first speaker 31 and the second speaker 32 and the sound radiated by the headphones 33.

[0057] 6 is a flowchart of the process executed by the control device 21. For example, the process of FIG. 6 is started when the user operates the keyboard 11.

[0058] When the process starts, the control device 21 (sound source unit 41) generates an audio signal S in response to a user's operation on the keyboard 11 (P1). The control device 21 supplies the audio signal S to the first speaker 31 (P2). The control device 21 (reverberation generation unit 42) generates a reverberation signal X representing the waveform of a reverberant sound corresponding to the audio signal S (P3).

[0059] The control device 21 (signal processing unit 50) generates a reverberation signal Z by performing binaural processing and transaural processing on the reverberation signal X (P4, P5). Specifically, the control device 21 (first processing unit 51) generates an intermediate signal Y by performing binaural processing on the reverberation signal X (P4). Furthermore, the control device 21 (second processing unit 52) ​​generates a reverberation signal Z by performing transaural processing on the intermediate signal Y (P5). The control device 21 supplies the reverberation signal Z to the second speaker 32 (P6). The control device 21 (reproduction processing unit 60) generates a playback signal W in accordance with the acoustic signal S and the intermediate signal Y (P7). The control device 21 supplies the playback signal W to the headphones 33 (P8).

[0060] B: Second embodiment A second embodiment will be described. Note that, for elements in the following exemplary aspects that have the same functions as those in the first embodiment, the same reference numerals as those in the first embodiment will be used, and detailed descriptions of each will be omitted as appropriate.

[0061] 7 is a front view of an electronic musical instrument 100 according to a second embodiment. The second embodiment differs from the first embodiment in the position of the second speaker 32. Other than the position of the second speaker 32, the second embodiment is the same as the first embodiment. Therefore, the second embodiment achieves the same effects as the first embodiment.

[0062] The second speaker 32 in the second embodiment is installed on the upper surface of the top plate 126 of the housing 12. Specifically, the second left channel speaker 32L and the second right channel speaker 32R are installed on the upper surface of the top plate 126 with a distance D2 therebetween in the X-axis direction. The position of the first speaker 31 is the same as in the first embodiment.

[0063] C: Third embodiment 8 is a front view of an electronic musical instrument 100 according to a third embodiment. The third embodiment differs from the first embodiment in the position of the second speaker 32. The rest of the electronic musical instrument is the same as the first embodiment. Therefore, the third embodiment also achieves the same effects as the first embodiment.

[0064] The second speaker 32 in the third embodiment is installed in front of the shelf 123 of the housing 12. That is, the second speaker 32 is installed below the keyboard 11 when viewed from the front of the electronic musical instrument 100. Specifically, the second left channel speaker 32L and the second right channel speaker 32R are installed in front of the shelf 123 (mouth bar) with a distance D2 between them in the X-axis direction. The position of the first speaker 31 is the same as in the first embodiment.

[0065] D: Fourth embodiment 9 is a front view of an electronic musical instrument 100 according to a fourth embodiment. In the fourth embodiment, the positions of the first speaker 31 and the second speaker 32 are different from those of the first embodiment. Other than the positions of the first speaker 31 and the second speaker 32, the fourth embodiment is the same as the first embodiment. Therefore, the fourth embodiment also achieves the same effects as the first embodiment.

[0066] The housing 12 of the fourth embodiment has a configuration in which the upper front panel 124 of the first embodiment is sufficiently low. That is, the upper front panel 124 is a long flat plate material extending along the X-axis. A top panel 126 is installed above the upper front panel 124, and a music stand 127 is installed on the top surface of the top panel 126. The music stand 127 is positioned in front of or diagonally below the head of a user playing the electronic musical instrument 100.

[0067] The second speaker 32 is installed on the upper front panel 124. Specifically, the second speaker 32 is installed between the music stand 127 and the keyboard 11 when viewed from the front of the electronic musical instrument 100. The second speaker 32 is installed in the center of the upper front panel 124 in the direction of the X-axis. On the other hand, the first speaker 31 is also installed on the upper front panel 124. Specifically, the first left channel speaker 31L is located to the left of the second speaker 32, and the first right channel speaker 31R is located to the right of the second speaker 32. In other words, the second speaker 32 is located between the first left channel speaker 31L and the first right channel speaker 31R.

[0068] E: Modified Example Specific modified embodiments that can be added to each of the above-described embodiments are exemplified below. Multiple embodiments arbitrarily selected from the above-described embodiments and the modified embodiments exemplified below may be combined as appropriate within the scope of not mutually contradicting each other.

[0069] (1) The positions of the first speaker 31 and the second speaker 32 are not limited to the positions exemplified in the above-described embodiments. For example, the fourth embodiment exemplifies an embodiment in which both the first speaker 31 and the second speaker 32 are located above the keyboard 11. Similarly, in the first to third embodiments, both the first speaker 31 and the second speaker 32 may be installed above the keyboard 11. Furthermore, the first speaker 31 configured separately from the housing 12 may be connected to the control system 20 by wire or wirelessly. Similarly, the second speaker 32 configured separately from the housing 12 may be connected to the control system 20 by wire or wirelessly.

[0070] (2) In the above embodiments, the signal acquisition unit 40 generates the acoustic signal S and the reverberation signal X. However, the method by which the signal acquisition unit 40 acquires the acoustic signal S and the reverberation signal X is not limited to the above examples. For example, the signal acquisition unit 40 may receive one or both of the acoustic signal S and the reverberation signal X from an external device via a wired or wireless connection. Therefore, the sound source unit 41 and the reverberation generation unit 42 (42L, 42R) may be omitted from the signal acquisition unit 40. As can be understood from the above explanation, the signal acquisition unit 40 is comprehensively expressed as an element that acquires the acoustic signal S and the reverberation signal X. The "acquisition" by the signal acquisition unit 40 encompasses both the operation of generating a signal by itself and the operation of receiving a signal from an external device.

[0071] (3) In the above-described embodiments, a single acoustic signal S (SL, SR) is shared for sound emission by the first speaker 31 and sound emission by the headphones 33. However, the sound source unit 41 may separately generate the acoustic signal S for speaker playback and the acoustic signal S for headphone playback. The acoustic signal S for speaker playback is a signal adjusted to have sound quality suitable for playback by the first speaker 31. The reverberation generation unit 42 (42L, 42R) generates a reverberation signal X (XL, XR) from the acoustic signal S for speaker playback. On the other hand, the acoustic signal S for headphone playback is a signal adjusted to have sound quality suitable for playback by the headphones 33. Note that the above-described embodiments can also be expressed as embodiments in which the sound source unit 41 includes a first sound source unit that generates the acoustic signal S for speaker playback and a second sound source unit that generates the acoustic signal S for headphone playback.

[0072] (4) In the above-described embodiments, the playback signal W is supplied to the headphones 33. However, earphones without a headband 331 to be worn on the user's head may be used instead of the headphones 33. Note that it may be interpreted that one of the headphones 33 and the earphones includes the other. Also, the playback processing unit 60 may be omitted.

[0073] (5) In the above-described embodiments, the first speaker 31 includes a single first left channel speaker 31L. However, the first left channel speaker 31L may be composed of a plurality of speakers. For example, the first left channel speaker 31L may be composed of a plurality of speakers with different playback bands. The positions of the speakers may be arbitrary. Similarly, the first right channel speaker 31R may be composed of a plurality of speakers. For example, the first right channel speaker 31R may be composed of a plurality of speakers with different playback bands. The positions of the speakers may be arbitrary.

[0074] (6) In the above embodiments, a keyboard instrument is exemplified as the electronic musical instrument 100, but the present disclosure also applies to electronic musical instruments 100 other than keyboard instruments. Furthermore, the electronic musical instrument 100 is an example of an acoustic system, and the present disclosure also applies to acoustic systems other than the electronic musical instrument 100. For example, the present disclosure applies to any acoustic system that has the function of emitting sound, such as PA (Public Address) equipment, AV (Audio Visual) equipment, karaoke equipment, or car stereo.

[0075] (7) As described above, the functions of the electronic musical instrument 100 (control system 20) according to each of the above-described embodiments are realized through cooperation between one or more processors constituting the control device 21 and a program stored in the storage device 22. The programs exemplified above can be provided in a form stored on a computer-readable recording medium and installed on a computer. The recording medium is, for example, a non-transitory recording medium, such as an optical recording medium (optical disk) such as a CD-ROM, but also includes any known type of recording medium, such as a semiconductor recording medium or a magnetic recording medium. Note that a non-transitory recording medium includes any recording medium other than a transitory, propagating signal, and does not exclude volatile recording media. Furthermore, in a configuration in which a distribution device distributes a program via a communication network, the recording medium storing the program in the distribution device corresponds to the non-transitory recording medium described above.

[0076] F: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0077] An acoustic system according to one aspect (aspect 1) of the present disclosure includes a signal acquisition unit that acquires an acoustic signal and a first reverberation signal representing the waveform of a reverberation sound corresponding to the acoustic signal, a signal processing unit that generates a second reverberation signal by performing binaural processing and transaural processing on the first reverberation signal, a first speaker that radiates sound corresponding to the acoustic signal, and a dipole-type second speaker that radiates reverberation sound corresponding to the second reverberation signal.

[0078] According to the above-described embodiment, a direct sound (dry sound) corresponding to an acoustic signal is emitted from a first speaker. Meanwhile, a second reverberation signal is generated by performing binaural processing and transaural processing on a first reverberation signal representing a waveform of a reverberation sound corresponding to the acoustic signal. A reverberation sound corresponding to the second reverberation signal is emitted from a dipole-type second speaker. Therefore, compared to a configuration in which binaural processing and transaural processing are performed on a signal including both a direct sound and a reverberation sound, it is possible to emit a reverberation sound that allows a user to perceive a sufficient sense of depth or spaciousness while suppressing delay of the direct sound.

[0079] Since the delay of reverberant sound is hardly perceptible, the delay of reverberant sound caused by signal processing by the signal processing unit is not a particular problem. Furthermore, in a configuration in which binaural processing and transaural processing are performed on a signal containing both direct sound and reverberant sound, the timbre of the direct sound may change before and after processing. In the configuration of the present disclosure, binaural processing and transaural processing are performed on a first reverberant signal representing the waveform of reverberant sound corresponding to the acoustic signal. Therefore, the direct sound emitted from the first speaker does not experience a change in timbre due to binaural processing or transaural processing.

[0080] "Binaural processing" is signal processing that localizes a sound image (virtual speaker) at a position distant from the listening position when listening with headphones. Specifically, "binaural processing" is realized by adding (convolving) the head-related transfer characteristics between the position of the virtual speaker and the position of the listener's both ears to the first acoustic signal. In other words, "binaural processing" is signal processing that processes the first reverberation signal with a filter of the head-related transfer function. For example, binaural processing is performed so that the sound image (virtual speaker) is localized at a position distant from the acoustic system.

[0081] "Transaural processing" is a signal processing method that reduces the components corresponding to the transfer characteristics from the position of the second speaker to the position of the listener's ears, allowing the listener to hear a signal equivalent to the signal after binaural processing. Specifically, "transaural processing" is achieved by convolving (adding) the inverse characteristics of the transfer characteristics of the reproduced sound field to the reverberation signal generated from the first reverberation signal by binaural processing. In other words, "transaural processing" is a signal processing method that processes the reverberation signal generated by binaural processing using a filter with the inverse characteristics of the reverberation signal.

[0082] A "dipole" speaker is a speaker that allows a listener to perceive a three-dimensional sound field by using two speakers placed close to each other.

[0083] An "acoustic system" is any system that has a signal processing function and a sound emitting function. For example, various electronic musical instruments that emit sound are examples of "acoustic systems." Also included in the term "acoustic systems" are various systems such as various audio equipment, karaoke machines, car stereos, and PA equipment.

[0084] In a specific example (Aspect 2) of Aspect 1, the signal processing unit performs the binaural processing and the transaural processing so that a virtual speaker of a reverberation sound corresponding to the second reverberation signal exists at a position distant from the acoustic system. According to the above aspect, the listener can sufficiently perceive a sense of depth or spaciousness from the reverberation sound radiated from the second speaker.

[0085] In a specific example (Aspect 3) of Aspect 1 or Aspect 2, the signal processing unit includes a first processing unit that performs the binaural processing on the first reverberation signal to generate an intermediate signal, and a second processing unit that performs the transaural processing on the intermediate signal to generate the second reverberation signal, and further includes an adder that generates a playback signal by adding the intermediate signal and the acoustic signal and outputs the playback signal to headphones or earphones. According to the above aspect, a listener can perceive virtual speakers generated by binaural processing through headphones or earphones.

[0086] A specific example (Aspect 4) of Aspect 3 further includes a delay unit that delays the intermediate signal, and the adder unit adds the signal delayed by the delay unit to the acoustic signal. According to the above aspect, a playback signal is generated by adding the intermediate signal delayed by the delay unit to the acoustic signal. Therefore, it is possible to make the delay of the reverberant sound relative to the direct sound closer to each other between the sound radiated by the first and second speakers and the sound radiated by headphones or earphones. Note that the amount of delay applied to the intermediate signal by the delay unit is arbitrary, but is set to a delay amount that is close to or equal to the processing delay due to transaural processing, for example.

[0087] In a specific example (Aspect 5) of any of Aspects 1 to 4, the acoustic signal includes a left channel acoustic signal and a right channel acoustic signal, the first speaker includes a first left channel speaker that radiates sound corresponding to the left channel acoustic signal and a first right channel speaker that radiates sound corresponding to the right channel acoustic signal, the second reverberation signal includes a second left channel reverberation signal and a second right channel speaker that radiates sound corresponding to the left channel second reverberation signal, and the second speaker includes a second left channel speaker that radiates sound corresponding to the left channel second reverberation signal and a second right channel speaker that radiates sound corresponding to the right channel second reverberation signal, and the distance between the first left channel speaker and the first right channel speaker is wider than the distance between the second left channel speaker and the second right channel speaker. According to the above aspect, the distance between the first left channel speaker and the first right channel speaker that constitute the first speaker is wider than the distance between the second left channel speaker and the second right channel speaker that constitute the second speaker, so that the listener can adequately perceive a sense of depth or spaciousness even for direct sounds corresponding to acoustic signals.

[0088] The first left channel speaker may be composed of one speaker or may be composed of multiple speakers that emit sounds in different frequency bands. Similarly, the first right channel speaker may be composed of one or more speakers.

[0089] In a specific example (aspect 6) of aspect 5, the signal processing unit performs the binaural processing and the transaural processing so that the first virtual speaker and the second virtual speaker of the reverberation sound corresponding to the second reverberation signal are located on opposite sides of a reference plane located midway between the first right channel speaker and the first left channel speaker. According to the above aspect, since the first virtual speaker and the second virtual speaker of the reverberation sound are located on opposite sides of the reference plane, the listener can sufficiently perceive a sense of depth or spaciousness from the reverberation sound radiated from the second speaker.

[0090] The reference plane is, for example, a plane equidistant from the central axis of the first right channel speaker and the central axis of the first left channel speaker. Alternatively, the reference plane may be a plane equidistant from the central axis of the second right channel speaker and the central axis of the second left channel speaker.

[0091] An electronic musical instrument according to one aspect (aspect 7) of the present disclosure includes an operation receiving unit that receives performance operations from a user, a signal generating unit that generates an acoustic signal in response to the operation on the operation receiving unit, a reverberation generating unit that generates a first reverberation signal representing the waveform of a reverberation sound corresponding to the acoustic signal, a signal processing unit that generates a second reverberation signal by performing binaural processing and transaural processing on the first reverberation signal, a first speaker that radiates sound in response to the acoustic signal, and a dipole-type second speaker that radiates reverberation sound in response to the second reverberation signal.

[0092] In a specific example (aspect 8) of aspect 7, the acoustic signal includes a left channel acoustic signal and a right channel acoustic signal, the first speaker includes a first left channel speaker that radiates sound corresponding to the left channel acoustic signal and a first right channel speaker that radiates sound corresponding to the right channel acoustic signal, the second reverberation signal includes a second left channel reverberation signal and a second right channel reverberation signal, the second speaker includes a second left channel speaker that radiates sound corresponding to the left channel reverberation signal and a second right channel speaker that radiates sound corresponding to the right channel reverberation signal, the operation receiving unit is a keyboard on which a plurality of keys are arranged, and the first left channel speaker and the second left channel speaker are located on the left side, and the first right channel speaker and the second right channel speaker are located on the right side, across a reference plane that is perpendicular to the direction in which the plurality of keys are arranged and passes through the midpoint of the keyboard in that direction. According to the above aspect, the first left channel speaker and the second left channel speaker are located on the left side of the reference plane, and the first right channel speaker and the second right channel speaker are located on the right side of the reference plane, so that the listener can sufficiently perceive a sense of depth or spaciousness for both the sound corresponding to the acoustic signal and the reverberation sound corresponding to the second reverberation signal.

[0093] In a specific example (Aspect 9) of Aspect 7 or Aspect 8, a housing is provided in which the first speaker and the second speaker are installed, and the signal processing unit performs the binaural processing and the transaural processing so that a virtual speaker of reverberation sound corresponding to the second reverberation signal exists at a position spaced apart from the housing on the outside. According to the above aspect, the listener can sufficiently perceive a sense of depth or spaciousness from the reverberation sound radiated from the second speaker. [Explanation of symbols]

[0094] 100...electronic musical instrument, 11...keyboard, 12...casing, 121...right arm, 122...left arm, 123...shelf, 124...upper front panel, 125...lower front panel, 126...top panel, 127...music stand, 13...key, 20...control system, 21...control device, 22...storage device, 23...detection device, 24...playback device, 31...first speaker, 31L...first left channel speaker, 31R...first right channel speaker, 32...second speaker, 32L...second left channel speaker, 32R...second right channel speaker, 33...headphones, 33L... Left ear speaker, 33R...right ear speaker, 331...headband, 200...acoustic processing unit, 40...signal acquisition unit, 41...sound source unit, 42 (42L, 42R)...reverberation generation unit, 50...signal processing unit, 51...first processing unit, 511 (511a, 511b, 511c, 511d)...characteristics assignment unit, 512 (512L, 512R)...addition unit, 52...second processing unit, 521 (521a, 521b, 521c, 521d)...characteristics assignment unit, 522 (522L, 522R)...addition unit, 60...playback processing unit, 61...delay unit, 62...addition unit.

Claims

1. a signal acquisition unit that acquires an acoustic signal and a first reverberation signal that represents a waveform of a reverberation sound corresponding to the acoustic signal; a signal processing unit that performs signal processing including binaural processing and transaural processing on the first reverberation signal to generate a second reverberation signal; a first speaker that emits a sound in response to the acoustic signal; a second speaker that emits a reverberation sound according to the second reverberation signal; An audio system comprising:

2. The signal processing unit performs the binaural processing and the transaural processing so that a virtual speaker of a reverberant sound corresponding to the second reverberant signal exists at a position separated from the acoustic system. The sound system of claim 1.

3. The signal processing unit a first processing unit that generates an intermediate signal by performing the binaural processing on the first reverberation signal; a second processing unit that performs the transaural processing on the intermediate signal to generate the second reverberation signal, The audio signal processing device further includes an adder that generates a playback signal by adding the intermediate signal and the acoustic signal and outputs the playback signal to headphones or earphones.

3. The acoustic system of claim 1.

4. a delay unit that delays the intermediate signal; The adding unit adds the signal delayed by the delay unit and the acoustic signal. The acoustic system of claim 3.

5. the acoustic signals include a left channel acoustic signal and a right channel acoustic signal; The first speaker is a first left channel speaker that emits sound in accordance with the left channel acoustic signal; a first right channel speaker that emits sound in accordance with the right channel acoustic signal; Including, the second reverberation signals include a second reverberation signal for a left channel and a second reverberation signal for a right channel; The second speaker is a second left channel speaker that emits a sound corresponding to the second reverberation signal of the left channel; a second right channel speaker that radiates a sound corresponding to the second reverberation signal of the right channel; Including, The distance between the first left channel speaker and the first right channel speaker is wider than the distance between the second left channel speaker and the second right channel speaker.

5. The acoustic system according to claim 1.

6. The signal processing unit performs the binaural processing and the transaural processing so that a first virtual speaker and a second virtual speaker of a reverberation sound corresponding to the second reverberation signal are positioned on opposite sides of a reference plane located midway between the first right channel speaker and the first left channel speaker. The sound system of claim 5.

7. The second speaker is a dipole speaker. The sound system of claim 1.

8. an operation receiving unit that receives performance operations by a user; a signal acquiring unit that acquires an acoustic signal corresponding to an operation performed on the operation accepting unit and a first reverberation signal that represents a waveform of a reverberation sound corresponding to the acoustic signal; a signal processing unit that performs signal processing including binaural processing and transaural processing on the first reverberation signal to generate a second reverberation signal; a first speaker that emits a sound in response to the acoustic signal; a second speaker that emits a reverberation sound according to the second reverberation signal; An electronic musical instrument comprising:

9. the acoustic signals include a left channel acoustic signal and a right channel acoustic signal; The first speaker is a first left channel speaker that emits sound in accordance with the left channel acoustic signal; a first right channel speaker that emits sound in accordance with the right channel acoustic signal; Including, the second reverberation signals include a second reverberation signal for a left channel and a second reverberation signal for a right channel; The second speaker is a second left channel speaker that emits a sound corresponding to the left channel reverberation signal; a second right channel speaker that emits a sound corresponding to the right channel reverberation signal; Including, the operation reception unit is a keyboard on which a plurality of keys are arranged, The first left channel speaker and the second left channel speaker are located on the left side, and the first right channel speaker and the second right channel speaker are located on the right side, across a reference plane that is perpendicular to the direction in which the keys are arranged and passes through the midpoint of the keyboard in that direction.

9. The electronic musical instrument of claim 8.

10. a housing in which the first speaker and the second speaker are installed, The signal processing unit performs the binaural processing and the transaural processing so that a virtual speaker of a reverberation sound corresponding to the second reverberation signal exists at a position spaced apart from the outside of the housing.

10. The electronic musical instrument according to claim 8 or claim 9.

11. Acquiring an acoustic signal and a first reverberation signal representing a waveform of a reverberation sound corresponding to the acoustic signal; performing signal processing on the first reverberant signal, including binaural processing and transaural processing, to generate a second reverberant signal; providing the acoustic signal to a first speaker; providing the second reverberation signal to a second speaker; Acoustic processing methods.

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