Sound output device and mobile unit

Abstract

To provide a sound output device that effectively emphasizes rotating body sounds in response to a behavior of a moving body.SOLUTION: A sound output device 2 includes: a sound generating unit 14 that generates a sound signal indicating a sound to emphasize an engine sound emitted from an engine 10 based on the rotation number of the engine 10; a vehicle information acquiring unit 16 that acquires vehicle information indicating a state of a vehicle; a modulation adding unit 18 that applies predetermined processing to the sound signal considering a behavior of the vehicle based on the vehicle information; and an output unit 24 that outputs the sound signal to which the predetermined processing is applied to a speaker 12 mounted on the vehicle.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a sound output device and a moving body.

Background Art

[0002] In a vehicle equipped with an engine, a sound output device for outputting a pseudo engine sound that simulates an actual engine sound from a speaker in the vehicle interior is known (see, for example, Patent Document 1). By this pseudo engine sound, the actual engine sound from the engine heard in the vehicle interior is emphasized, and thus the driver can easily grasp the behavior of the vehicle linked to the driving operation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, as the above-described sound output device, a type that generates a pseudo engine sound based on the engine speed has been proposed. However, in this type of sound output device, the following problems occur.

[0005] Depending on the type of vehicle (for example, a series hybrid vehicle or the like), the engine speed may be constantly constant. In such a case, in the above-described sound output device, although the vehicle is accelerating or decelerating, the timbres of the actual engine sound and the pseudo engine sound both become constant. As a result, there arises a problem that the behavior of the vehicle and the sound (actual engine sound and pseudo engine sound) heard in the vehicle interior do not match, and the driver feels a sense of discomfort in the driving operation.

[0006] Therefore, this disclosure provides a sound output device and a mobile body that can effectively amplify the sound of a rotating body in accordance with the behavior of the mobile body. [Means for solving the problem]

[0007] A sound output device according to one aspect of the present disclosure is a sound output device mounted on a mobile body equipped with a rotating body that generates rotational driving force, comprising: a generation unit that generates a sound signal indicating a sound for emphasizing the rotating body sound emitted from the rotating body based on the rotational speed of the rotating body; an acquisition unit that acquires mobile body information indicating the state of the mobile body; a processing unit that applies predetermined processing to the sound signal based on the mobile body information, taking into account the behavior of the mobile body; and an output unit that outputs the sound signal, which has undergone the predetermined processing, to a speaker mounted on the mobile body.

[0008] These comprehensive or specific embodiments may be implemented as a system, method, integrated circuit, computer program, or recording medium such as a computer-readable CD-ROM, or as any combination of a system, method, integrated circuit, computer program, and recording medium. [Effects of the Invention]

[0009] The sound output device and the like of this disclosure can effectively amplify the sound of a rotating body in accordance with the behavior of a moving body. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows a vehicle equipped with a sound output device according to Embodiment 1. [Figure 2] This is a block diagram showing the configuration of the sound output device according to Embodiment 1. [Figure 3] This is a block diagram showing the configuration of the modulation addition section of the sound output device according to Embodiment 1. [Figure 4] This is a diagram illustrating the function of the modulation addition unit of the sound output device according to Embodiment 1. [Figure 5] This is a block diagram showing the configuration of a sound output device related to a comparative example. [Figure 6] This graph shows the time variation of the frequency of the simulated engine sound output from the speaker in the comparative example sound output device. [Figure 7] This graph shows the time variation of the frequency of the simulated engine sound output from the speaker in the sound output device according to Embodiment 1. [Figure 8] This is a block diagram showing the configuration of the modulation addition section of the sound output device according to Embodiment 2. [Figure 9] This is a diagram illustrating the function of the modulation addition unit of the sound output device according to Embodiment 2. [Figure 10] This is a block diagram showing the configuration of the sound output device according to Embodiment 3. [Figure 11] This graph shows the time variation of the frequency of the simulated engine sound output from the speaker in the sound output device according to Embodiment 3. [Figure 12] This graph shows the time variation of the frequency of the simulated engine sound output from the speaker in a sound output device according to a modified embodiment of Embodiment 3. [Figure 13] This is a block diagram showing the configuration of the sound output device according to Embodiment 4. [Modes for carrying out the invention]

[0011] To solve the above-mentioned problems, a sound output device according to one aspect of the present disclosure is a sound output device mounted on a mobile body equipped with a rotating body that generates rotational driving force, comprising: a generation unit that generates a sound signal indicating a sound for emphasizing the rotating body sound emitted from the rotating body based on the rotational speed of the rotating body; an acquisition unit that acquires mobile body information indicating the state of the mobile body; a processing unit that applies predetermined processing to the sound signal based on the mobile body information, taking into account the behavior of the mobile body; and an output unit that outputs the sound signal, which has undergone the predetermined processing, to a speaker mounted on the mobile body.

[0012] According to this aspect, the generation unit generates a sound signal based on the rotational speed of the rotating body, and the processing unit performs a predetermined process on the sound signal in consideration of the behavior of the moving body based on the moving body information. As a result, the frequency components of the sound (hereinafter referred to as "pseudo-rotating body sound") for emphasizing the actual rotating body sound output from the speaker include components based on the rotating body and components based on the behavior of the moving body. Therefore, even if the rotational speed of the rotating body is constant, the timbre of the pseudo-rotating body sound output from the speaker changes according to the behavior of the moving body. As a result, it is possible to match the behavior of the moving body with the sound (actual rotating body sound and pseudo-rotating body sound output from the speaker) heard inside the moving body, and it is possible to effectively emphasize the rotating body sound according to the behavior of the moving body.

[0013] For example, the generation unit generates a plurality of the sound signals each indicating a plurality of the sounds having different frequencies, the processing unit adds modulation with a modulation frequency or a modulation degree based on the moving body information to each of the plurality of sound signals as the predetermined process, and adds the plurality of sound signals to which the modulation has been added, and the output unit may be configured to output the added plurality of sound signals to the speaker.

[0014] According to this aspect, it is possible to effectively emphasize the rotating body sound according to the behavior of the moving body with a simple configuration.

[0015] For example, the modulation may be configured to be any one of AM (Amplitude Modulation) modulation and FM (Frequency Modulation) modulation.

[0016] For example, the processing unit may be configured to further perform a filtering process on each of the plurality of sound signals to which the modulation has been added as the predetermined process.

[0017] According to this embodiment, the timbre of the pseudo-rotating body sound output from the speaker can be made to more closely match the timbre of the sound that corresponds to the behavior of the moving body.

[0018] For example, the processing unit may be configured to further filter the summed plurality of sound signals as a predetermined process.

[0019] According to this embodiment, the timbre of the pseudo-rotating body sound output from the speaker can be made to more closely match the timbre of the sound that corresponds to the behavior of the moving body.

[0020] For example, the processing unit may be configured to dynamically change the filter characteristics of the filtering process.

[0021] According to this embodiment, the timbre of the pseudo-rotating body sound output from the speaker can be more effectively brought closer to the timbre of a sound that matches the behavior of a moving object.

[0022] For example, the processing unit may be configured to perform the predetermined processing by adding modulation to each of the plurality of sound signals at the modulation frequency based on the mobile information, and to reduce the modulation frequency when the maximum value of the frequency of the sound output from the speaker reaches a threshold.

[0023] According to this embodiment, a simulated gear shifting sensation can be expressed by the simulated rotating body sound.

[0024] For example, the generation unit may generate a plurality of sound signals, each representing a plurality of sounds with different frequencies; the processing unit may, as a predetermined process, generate an embellished sound signal that represents an embellished sound that takes into account the behavior of the moving body based on the moving body information, and add the plurality of sound signals and the embellished sound signal; and the output unit may be configured to output the added plurality of sound signals and the embellished sound signal to the speaker.

[0025] According to this embodiment, with a simple configuration, the sound of a rotating body can be effectively emphasized in accordance with the behavior of a moving body.

[0026] For example, the processing unit may be configured to perform the predetermined processing on the sound signal on the condition that the rotational speed of the rotating body reaches a first threshold, or that the amount of change per unit time of the rotational speed of the rotating body exceeds a second threshold.

[0027] According to this embodiment, predetermined processing can be applied to the sound signal at an appropriate timing, thereby reducing the processing load on the processing unit.

[0028] For example, the speaker may be mounted in multiple locations on the mobile body, and the output unit may be configured to dynamically switch between the speakers that output the sound signal that has undergone the predetermined processing.

[0029] According to this embodiment, the behavior of a moving object can be effectively represented by pseudo-rotating sound.

[0030] A mobile body according to one aspect of the present disclosure is a mobile body that moves with a user on board, comprising: a rotating body that generates rotational driving force; a sound output device according to any one of claims 1 to 10, which outputs a sound signal indicating a sound for emphasizing the rotating body sound emitted from the rotating body; and a speaker to which the sound signal from the sound output device is input.

[0031] According to this embodiment, as described above, the rotational sound can be effectively emphasized in accordance with the behavior of the moving body.

[0032] These comprehensive or specific embodiments may be implemented as a system, method, integrated circuit, computer program, or recording medium such as a computer-readable CD-ROM, or as any combination of a system, method, integrated circuit, computer program, or recording medium.

[0033] The embodiments will be described in detail below with reference to the drawings.

[0034] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit this disclosure. Furthermore, among the components in the following embodiments, those not described in the independent claim representing the highest-level concept will be described as optional components.

[0035] (Embodiment 1) [1-1. Sound Output Device Configuration] The configuration of the sound output device 2 according to Embodiment 1 will be described with reference to Figures 1 to 4. Figure 1 is a diagram showing a vehicle 4 equipped with the sound output device 2 according to Embodiment 1. Figure 2 is a block diagram showing the configuration of the sound output device 2 according to Embodiment 1. Figure 3 is a block diagram showing the configuration of the modulation addition unit 18 of the sound output device 2 according to Embodiment 1. Figure 4 is a diagram for explaining the function of the modulation addition unit 18 of the sound output device 2 according to Embodiment 1.

[0036] As shown in Figure 1, the sound output device 2 is mounted on a vehicle 4, such as an automobile. The vehicle 4 is an example of a mobile body that moves with a user, such as a driver 6, on board. The engine room 8 of the vehicle 4 is equipped with an engine 10 (an example of a rotating body) that generates rotational driving force. If the vehicle 4 is, for example, a series hybrid vehicle, the drive source of the vehicle 4 is a motor (not shown), and the engine 10 is used for power generation. If the vehicle 4 is, for example, a CVT (Continuously Variable Transmission) vehicle, the drive source of the vehicle 4 is the engine 10.

[0037] The interior of vehicle 4 is equipped with multiple speakers 12. These multiple speakers 12 include, for example, a right front speaker located in the right (driver's side) front door, a left front speaker located in the left (passenger side) front door, a right rear speaker located in the right rear door, and a left rear speaker located in the left rear door. For the sake of explanation, only one speaker 12 (right front speaker) is shown in Figure 1.

[0038] The sound output device 2 is a device that outputs a simulated engine sound from multiple speakers 12 to enhance the actual engine sound (an example of a rotating sound) from the engine 10 that can be heard inside the cabin of the vehicle 4. The simulated engine sound is a sound that imitates the actual engine sound. In this way, by enhancing the actual engine sound with the simulated engine sound, the driver 6 can more easily grasp the behavior of the vehicle 4 in conjunction with the driving operation, and the driver 6's sense of driving is enhanced.

[0039] As shown in Figure 2, the sound output device 2 comprises a plurality of sound generation units 14 (an example of a generation unit), a vehicle information acquisition unit 16, a plurality of modulation addition units 18 (an example of a processing unit), a plurality of volume adjustment units 20, a plurality of adders 22 (an example of a processing unit), and a plurality of output units 24.

[0040] Each of the multiple sound generation units 14 acquires rotational speed information indicating the rotational speed of the engine 10 from a rotational speed sensor (not shown) located on the engine 10. Each of the multiple sound generation units 14 generates multiple sound signals (digital signals) that each represent multiple pseudo-engine sounds (an example of multiple sounds) with different frequencies, based on the rotational speed of the engine 10 indicated by the rotational speed information. The frequencies of each of the multiple pseudo-engine sounds are, for example, the frequency synchronized with the rotational speed of the engine 10 as the first order, followed by the second, 2.5, fourth, and so on.

[0041] The vehicle information acquisition unit 16 acquires vehicle information (an example of mobile information) that indicates the state of the vehicle 4. The vehicle information includes, for example, the vehicle speed of the vehicle 4, the acceleration of the vehicle 4, the rotational speed of the tires, the rotational speed of the tires, the rotational speed of the drive shaft, the rotational speed of the propeller shaft, GPS (Global Positioning System) location information, and image data captured by the drive recorder. This vehicle information changes according to the behavior of the vehicle 4 (acceleration and deceleration, etc.).

[0042] Each of the multiple modulation units 18 is provided in a one-to-one correspondence with each of the multiple sound generation units 14. Each of the multiple modulation units 18 adds AM (Amplitude Modulation) modulation to the multiple sound signals generated by the multiple sound generation units 14 at a modulation frequency based on vehicle information from the vehicle information acquisition unit 16. That is, each of the multiple modulation units 18 applies predetermined processing to the multiple sound signals based on the vehicle information, taking into account the behavior of the vehicle 4. Specifically, each of the multiple modulation units 18 adds AM modulation to the sound signal at a modulation frequency based on the vehicle information, for example, so that the frequency of the simulated engine sound increases as the vehicle 4 accelerates.

[0043] As shown in Figure 3, each of the multiple modulation units 18 includes a sound generation unit 26, a gain adjustment unit 28, a multiplier 30, and an adder 32. The sound generation unit 26 generates a sound signal (digital signal) representing a simulated engine sound based on vehicle information from the vehicle information acquisition unit 16. The gain adjustment unit 28 adjusts the gain of the sound signal generated by the sound generation unit 26. The multiplier 30 multiplies the sound signal generated by the sound generation unit 14 with the sound signal whose gain has been adjusted by the gain adjustment unit 28. The adder 32 adds the amplitude of the sound signal generated by the sound generation unit 14 with the amplitude of the sound signal multiplied by the multiplier 30.

[0044] As a result, the waveform of the sound signal to which AM modulation has been added at a modulation frequency based on vehicle information will be as shown in Figure 4(a), for example. In this case, as shown in Figure 4(b), the frequency components of the sound signal to which AM modulation has been added will include a component based on the engine 10 and multiple modulation components based on the behavior of the vehicle 4.

[0045] In this embodiment, each of the multiple modulation units 18 added AM modulation to multiple sound signals using a modulation frequency based on vehicle information from the vehicle information acquisition unit 16. However, the system is not limited to this, and AM modulation may also be added to multiple sound signals using a modulation degree based on vehicle information from the vehicle information acquisition unit 16. By changing the modulation degree, the magnitude of the modulation component shown in Figure 4(b) changes, and the magnitude of the pseudo-engine sound component can be controlled.

[0046] Each of the multiple volume adjustment units 20 is provided in a one-to-one correspondence with each of the multiple sound generation units 14. Each of the multiple volume adjustment units 20 adjusts the volume of each of the multiple sound signals from the multiple sound generation units 14, to which AM modulation has been added, based on vehicle information from the vehicle information acquisition unit 16. Specifically, each volume adjustment unit 20 adjusts the volume of the sound signal from the AM-modulated sound generation unit 14 so that, for example, the volume increases as the vehicle speed of the vehicle 4 increases.

[0047] Each of the multiple adders 22 adds up multiple sound signals whose volume has been adjusted by the multiple volume adjustment units 20.

[0048] Each of the multiple output units 24 is provided in a one-to-one correspondence with each of the multiple adders 22. Each of the multiple output units 24 outputs the multiple sound signals added by each of the multiple adders 22 to the multiple speakers 12. In addition, each of the multiple output units 24 converts the multiple sound signals added by the multiple adders 22 from digital signals to analog signals, amplifies them, and outputs them to the speakers 12.

[0049] Each of the multiple speakers 12 outputs a simulated engine sound based on the sound signal from the output unit 24. As a result, each of the multiple speakers 12 outputs a simulated engine sound that takes into account not only the rotational speed of the engine 10 but also the behavior of the vehicle 4.

[0050] The simulated engine sound output from each of the multiple speakers 12 amplifies the actual engine sound from the engine 10 heard inside the vehicle 4. In order to more effectively amplify the actual engine sound, the volume and other parameters of the simulated engine sound output from each speaker 12 may be weighted accordingly.

[0051] [1-2. Effects] Next, the effects obtained by the sound output device 2 according to Embodiment 1 will be explained while comparing it with the sound output device 100 according to the comparative example.

[0052] Here, the configuration of the sound output device 100 according to the comparative example will be described with reference to Figure 5. Figure 5 is a block diagram showing the configuration of the sound output device 100 according to the comparative example. In Figure 5, components identical to those of the sound output device 2 according to Embodiment 1 are denoted by the same reference numerals, and their descriptions are omitted.

[0053] As shown in Figure 5, the sound output device 100 according to the comparative example differs from the sound output device 2 according to Embodiment 1 in that it does not have multiple modulation addition units 18. As a result, in the sound output device 100 according to the comparative example, the simulated engine sound output from each of the multiple speakers 12 is a simulated engine sound that takes only the rotational speed of the engine 10 into consideration.

[0054] In the comparative example sound output device 100, the time variation of the frequency of the simulated engine sound output from each of the multiple speakers 12 is as shown in Figure 6, for example. Figure 6 is a graph showing the time variation of the frequency of the simulated engine sound output from the speakers 12 in the comparative example sound output device 100. In Figure 6, it is assumed that the engine 10 is rotating at a constant speed of 2000 rpm and the vehicle 4 is accelerating from time 0 (sec).

[0055] If vehicle 4 is, for example, a series hybrid vehicle, the rotational speed of engine 10 will always be constant. Also, if vehicle 4 is, for example, a CVT vehicle, when vehicle 4 is accelerating, the rotational speed of engine 10 will rise and then quickly stick to the upper limit. In the sound output device 100 according to the comparative example, when the rotational speed of engine 10 is constant in this way, as shown in Figure 6, the frequency components of the simulated engine sound output from each of the multiple speakers 12 include only components based on engine 10, so the frequencies of the simulated engine sound will be constant at, for example, 100Hz and 200Hz. As a result, even though vehicle 4 is accelerating, the timbres of the actual engine sound and the simulated engine sound remain constant, so the behavior of vehicle 4 and the sounds heard in the cabin of vehicle 4 (actual engine sound and simulated engine sound) do not match, resulting in the driver 6 feeling a sense of unease during driving.

[0056] In contrast, in the sound output device 2 according to Embodiment 1, as described above, a simulated engine sound that takes into account not only the rotational speed of the engine 10 but also the behavior of the vehicle 4 is output from each of the multiple speakers 12. Therefore, in the sound output device 2 according to Embodiment 1, the time change of the frequency of the simulated engine sound output from each of the multiple speakers 12 is as shown in Figure 7, for example. Figure 7 is a graph showing the time change of the frequency of the simulated engine sound output from the speakers 12 in the sound output device 2 according to Embodiment 1. Note that in Figure 7, it is assumed that the rotational speed of the engine 10 is constant at 2000 rpm and the vehicle 4 is accelerating from time 0 (sec).

[0057] In the sound output device 2 according to Embodiment 1, even when the rotational speed of the engine 10 is constant because the vehicle 4 is, for example, a series hybrid vehicle or a CVT vehicle, as shown in Figure 7, the frequency components of the simulated engine sound output from each of the multiple speakers 12 include a component based on the engine 10 and multiple modulation components based on the behavior of the vehicle 4. Therefore, the frequency of the simulated engine sound changes over time (i.e., according to the behavior of the vehicle 4). More specifically, as shown in Figure 7, the frequencies of the engine-based components (100Hz, 200Hz) are constant, but the frequencies of each of the multiple modulation components rise and fall relative to the engine-based component from time 0 (sec).

[0058] As a result, the tone of the simulated engine sound changes as the vehicle 4 accelerates, so that the behavior of the vehicle 4 and the sounds heard inside the vehicle 4's cabin (actual engine sound and simulated engine sound) match. This makes it easier for the driver 6 to grasp the behavior of the vehicle 4 in conjunction with the driving operation, thereby improving the driver's sense of driving. Therefore, the sound output device 2 according to Embodiment 1 can effectively emphasize the engine sound in accordance with the behavior of the vehicle 4.

[0059] In this embodiment, the above-described effects are obtained when the rotational speed of the engine 10 is constant, but the invention is not limited to this, and the above-described effects can also be obtained when the rotational speed of the engine 10 fluctuates rapidly. In this case, the amount of change per unit time of the rotational speed of the engine 10 may be monitored, and when the amount of change per unit time exceeds a threshold (an example of a second threshold), the operation of each of the multiple modulation addition units 18 may be turned on.

[0060] (Embodiment 2) The configuration of the sound output device 2A according to Embodiment 2 will be described with reference to Figures 8 and 9. Figure 8 is a block diagram showing the configuration of the modulation addition unit 18A of the sound output device 2A according to Embodiment 2. Figure 9 is a diagram illustrating the function of the modulation addition unit 18A of the sound output device 2A according to Embodiment 2. In each of the embodiments described below, the same reference numerals are used for components that are the same as those in Embodiment 1, and their descriptions are omitted.

[0061] In the sound output device 2A according to Embodiment 2, the configuration of the modulation addition unit 18A differs from that of Embodiment 1. Specifically, the modulation addition unit 18A adds FM (Frequency Modulation) modulation to the sound signal at a modulation frequency based on vehicle information from the vehicle information acquisition unit 16. That is, the modulation addition unit 18A applies predetermined processing to the sound signal based on the vehicle information, taking into account the behavior of the vehicle 4.

[0062] As shown in Figure 8, the modulation addition unit 18A includes a sound generation unit 26, a gain adjustment unit 28, and an adder 32A. The sound generation unit 26 generates a sound signal representing a simulated engine sound based on vehicle information from the vehicle information acquisition unit 16. The gain adjustment unit 28 adjusts the gain of the sound signal generated by the sound generation unit 26. The adder 32A adds a frequency synchronized with the rotational speed of the engine 10, indicated by the rotational speed information, to the frequency of the sound signal whose gain has been adjusted by the gain adjustment unit 28. The adder 32A outputs the addition result to the sound generation unit 14. As a result, FM modulation is added to the sound signal generated by the sound generation unit 14.

[0063] As a result, the sound signal to which FM modulation has been added at a modulation frequency based on vehicle information will be as shown in Figure 9(a), for example. In this case, as shown in Figure 9(b), the frequency components of the sound signal to which FM modulation has been added will include a component based on the engine 10 and multiple modulation components based on the behavior of the vehicle 4 (see Figure 1). Therefore, the same effects as in Embodiment 1 can be obtained in this embodiment as well.

[0064] (Embodiment 3) The configuration of the sound output device 2B according to Embodiment 3 will be described with reference to Figure 10. Figure 10 is a block diagram showing the configuration of the sound output device 2B according to Embodiment 3.

[0065] As shown in Figure 10, the sound output device 2B according to Embodiment 3 includes a plurality of filters 34 in addition to the configuration requirements described in Embodiment 1. Each of the plurality of filters 34 is provided in a one-to-one correspondence with a plurality of sound generation units 14. Each of the plurality of filters 34 filters each of the plurality of sound signals from the plurality of sound generation units 14 to which AM modulation has been added, based on rotational speed information from a rotational speed sensor (not shown). Specifically, each of the plurality of filters 34 is a high-pass filter, and attenuates only the frequency components of the sound signal that are below the frequency synchronized with the rotational speed indicated by the rotational speed information.

[0066] In the sound output device 2B according to Embodiment 3, the time variation of the frequency of the simulated engine sound output from each of the multiple speakers 12 is as shown in Figure 11, for example. Figure 11 is a graph showing the time variation of the frequency of the simulated engine sound output from the speakers 12 in the sound output device 2B according to Embodiment 3. In Figure 11, it is assumed that the engine 10 is rotating at a constant speed of 2000 rpm and that the vehicle 4 (see Figure 1) is accelerating from time 0 (sec).

[0067] As shown in Figure 11, multiple filters 34 cut out the lower-frequency modulation components of the pseudo-engine sound. More specifically, in Figure 7 described above, there were multiple modulation components whose frequency decreased from time 0 (sec) relative to the engine-based components (100Hz, 200Hz), but in Figure 11, these multiple modulation components are cut out. As a result, the same effect as in Embodiment 1 can be obtained, and the timbre of the pseudo-engine sound can be made closer to the timbre of the sound that matches the behavior of the vehicle 4, thereby more effectively creating the feeling of acceleration of the vehicle 4.

[0068] In this embodiment, each of the multiple sound signals from the multiple sound generation units 14 to which AM modulation has been added was filtered, but the invention is not limited to this, and the multiple sound signals added by the adder 22 may also be filtered. Furthermore, the filter characteristics (e.g., cutoff frequency) may be dynamically changed during filtering. This makes it possible to more effectively bring the timbre of the simulated engine sound closer to the timbre of the sound that matches the behavior of the vehicle 4.

[0069] Furthermore, Figure 12 is a graph showing the time variation of the frequency of the simulated engine sound output from speaker 12 in the sound output device 2B according to a modified example of Embodiment 3. As shown in Figure 12, the modulation frequency may be controlled to decrease when the maximum value of the simulated engine sound frequency reaches a set upper limit (an example of a threshold). This makes it possible to express a simulated gear shifting sensation with the simulated engine sound. This is also effective when there are limitations on the frequencies that can be generated due to system constraints.

[0070] (Embodiment 4) The configuration of the sound output device 2C according to Embodiment 4 will be described with reference to Figure 13. Figure 13 is a block diagram showing the configuration of the sound output device 2C according to Embodiment 4.

[0071] As shown in Figure 13, the sound output device 2C according to Embodiment 4 comprises a plurality of sound generation units 14, a vehicle information acquisition unit 16, a plurality of sound generation units 36 (an example of a processing unit), a plurality of volume adjustment units 20, a plurality of adders 22 (an example of a processing unit), and a plurality of output units 24.

[0072] Each of the multiple sound generation units 36 acquires vehicle information from the vehicle information acquisition unit 16. Based on the vehicle information, each of the multiple sound generation units 36 generates multiple embellishment sound signals, each representing multiple embellishment sounds with different frequencies. Each of the multiple embellishment sounds is a sound that simulates the actual engine sound, taking into account the behavior of the vehicle 4 (see Figure 1). Specifically, each of the multiple sound generation units 36 generates embellishment sounds based on the vehicle information such that, for example, the frequency of the embellishment sound increases as the vehicle 4 accelerates. The frequencies of the multiple embellishment sounds are, for example, the first frequency synchronized with the rotational speed of the engine 10, followed by the second, 2.5, fourth, and so on frequencies.

[0073] Each of the multiple volume adjustment units 20 is provided in a one-to-one correspondence with each of the multiple sound generation units 14 and each of the multiple sound generation units 36. Each of the multiple volume adjustment units 20 adjusts the volume of each of the multiple sound signals from the multiple sound generation units 14 and the multiple embellished sound signals from the multiple sound generation units 36 based on vehicle information from the vehicle information acquisition unit 16.

[0074] Each of the multiple adders 22 adds up multiple sound signals and multiple embellished sound signals whose volumes have been adjusted by the multiple volume adjustment units 20. In other words, the multiple sound generation units 36 and the multiple adders 22 apply predetermined processing to the multiple sound signals, taking into account the behavior of the vehicle 4.

[0075] Each of the multiple output units 24 outputs multiple sound signals and multiple embellished sound signals, each added by each of the multiple adders 22, to the multiple speakers 12. As a result, each of the multiple speakers 12 outputs a simulated engine sound that takes into account not only the rotational speed of the engine 10 but also the behavior of the vehicle 4.

[0076] Therefore, the same effects as in Embodiment 1 can be obtained in this embodiment as well.

[0077] (Other variations) Although sound output devices and mobile bodies relating to one or more embodiments have been described above based on the above embodiments, the present invention is not limited to the above embodiments. Without departing from the spirit of the present invention, various modifications that a person skilled in the art can conceive of may be applied to the above embodiments, or forms constructed by combining components from different embodiments or modifications may also be included within the scope of one or more embodiments.

[0078] In the embodiments described above, the case in which the sound output device 2 (2A, 2B, 2C) is mounted on a vehicle 4 has been explained, but the invention is not limited to this, and may be mounted on various moving objects such as aircraft, trains, or ships.

[0079] Furthermore, although the above embodiments describe the case where vehicle 4 is an automobile, the invention is not limited to this, and may be various types of vehicles such as construction machinery or agricultural machinery.

[0080] Furthermore, in each of the above embodiments, predetermined processing considering the behavior of the vehicle 4 was applied to the sound signal. However, rotational speed information from the rotational speed sensor may be monitored, and predetermined processing considering the behavior of the vehicle 4 may be applied to the sound signal only when the rotational speed of the engine 10 indicated by the rotational speed information reaches an upper limit or an arbitrary set value (an example of a first threshold). For example, in Embodiment 1 above, the operation of each of the multiple modulation addition units 18 may be switched from off to on at the timing when the rotational speed of the engine 10 reaches an upper limit or an arbitrary set value. This reduces the processing load when applying predetermined processing to the sound signal.

[0081] Furthermore, in each of the above embodiments, the frequency of the simulated engine sound is controlled according to the behavior of the vehicle 4, but the invention is not limited to this, and the volume of the simulated engine sound may also be controlled according to the behavior of the vehicle 4. That is, a predetermined process that takes into account the behavior of the vehicle 4 may be applied to the sound signal so that the volume of the simulated engine sound increases as the vehicle 4 accelerates.

[0082] Furthermore, although all of the multiple sound generation units 14 were operated in the above embodiments, the system is not limited to this, and the frequency of the simulated engine sound may be controlled according to the behavior of the vehicle 4 by appropriately switching the on / off operation of each of the multiple sound generation units 14. Alternatively, the multiple output units 24 may express the behavior of the vehicle 4 (acceleration or deceleration) with the simulated engine sound by dynamically switching the speaker 12 that outputs the simulated engine sound. For example, when the vehicle 4 is accelerating, the simulated engine sound may be output from the front speaker, and when the vehicle 4 is decelerating, the simulated engine sound may be output from the rear speaker. Alternatively, conversely, when the vehicle 4 is accelerating, the simulated engine sound may be output from the rear speaker, and when the vehicle 4 is decelerating, the simulated engine sound may be output from the front speaker.

[0083] (others) In the above embodiment, each component may be implemented by dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0084] The following cases are also included in this disclosure:

[0085] (1) Specifically, each of the above devices can be realized in a computer system consisting of a microprocessor, ROM, RAM, hard disk unit, display unit, keyboard, mouse, etc. A computer program is stored in the RAM or hard disk unit. Each device achieves its function by operating the microprocessor in accordance with the computer program. Here, a computer program is composed of a combination of multiple instruction codes that indicate commands to the computer in order to achieve a predetermined function.

[0086] (2) Some or all of the components constituting each of the above devices may be made up of a single system LSI (Large Scale Integration). A system LSI is a highly functional LSI manufactured by integrating multiple components onto a single chip, and specifically, it is a computer system that includes a microprocessor, ROM, RAM, etc. A computer program is stored in the ROM. The system LSI achieves its function by having the microprocessor load the computer program from the ROM into the RAM and perform calculations and other operations according to the loaded computer program.

[0087] (3) Some or all of the components constituting each of the above devices may consist of a removable IC card or a standalone module. The IC card or module is a computer system consisting of a microprocessor, ROM, RAM, etc. The IC card or module may include the above-mentioned multi-functional LSI. The IC card or module achieves its function by the operation of the microprocessor according to the computer program. The IC card or module may be tamper-resistant.

[0088] (4) The disclosure may be implemented in the manner described above. Alternatively, these methods may be implemented by a computer program implemented by a computer, or by a digital signal consisting of a computer program.

[0089] Furthermore, this disclosure may be implemented using computer-readable recording media, such as flexible disks, hard disks, CD-ROMs, MOs, DVDs, DVD-ROMs, DVD-RAMs, BDs, semiconductor memory, etc., on which computer programs or digital signals are recorded. Alternatively, it may be implemented using digital signals recorded on these recording media.

[0090] Furthermore, this disclosure may transmit computer programs or digital signals via telecommunications lines, wireless or wired communication lines, networks such as the Internet, data broadcasting, etc.

[0091] Furthermore, this disclosure relates to a computer system comprising a microprocessor and memory, wherein the memory stores a computer program, and the microprocessor may operate in accordance with the computer program.

[0092] Alternatively, the program or digital signal may be implemented by another independent computer system by recording and transferring it on a recording medium, or by transferring the program or digital signal via a network or the like.

[0093] (5) The above embodiments and the above modifications may be combined. [Industrial applicability]

[0094] This disclosure can be applied, for example, to a sound output device that outputs a simulated engine sound to a vehicle's speaker to enhance the engine sound. [Explanation of Symbols]

[0095] 2,2A,2B,2C,100 Sound Output Device 4 vehicles 6. Driver 8. Engine Room 10 Engines 12 speakers 14,26,36 Sound generation section 16. Vehicle Information Acquisition Unit 18,18A Modulation Addition Section 20 Volume control section 22,32,32A Adder 24 Output section 28 Gain adjustment section 30 Multiplier 34 filters

Claims

1. A sound output device mounted on a mobile body equipped with a rotating body that generates rotational driving force, A generation unit generates a sound signal that indicates a sound for emphasizing the rotational sound emitted from the rotating body, based on the rotational speed of the rotating body. An acquisition unit that acquires mobile body information indicating the state of the mobile body, A processing unit that applies predetermined processing to the sound signal, taking into account the behavior of the moving object based on the moving object information, The system includes an output unit that outputs the sound signal, which has undergone the predetermined processing, to a speaker mounted on the mobile body, The generation unit generates a plurality of sound signals, each representing a plurality of sounds with different frequencies. The processing unit, as a predetermined process, modulates each of the plurality of sound signals with a modulation frequency based on the mobile body information, adds the plurality of sound signals with the modulation added, and reduces the modulation frequency when the maximum value of the sound frequency output from the speaker reaches a threshold. The output unit outputs the summed plurality of sound signals to the speaker. Sound output device.

2. The modulation is either AM (Amplitude Modulation) modulation or FM (Frequency Modulation) modulation. The sound output device according to claim 1.

3. The processing unit further performs a filter process on each of the plurality of sound signals to which the modulation has been added, as part of the predetermined processing. The sound output device according to claim 1 or 2.

4. The processing unit further performs a filter process on the summed sound signals as a predetermined process. The sound output device according to claim 1 or 2.

5. The processing unit dynamically changes the filter characteristics of the filter processing. The sound output device according to claim 3 or 4.

6. The processing unit performs the predetermined processing on the sound signal on the condition that the rotational speed of the rotating body reaches a first threshold, or that the rate of change per unit time of the rotational speed of the rotating body exceeds a second threshold. A sound output device according to any one of claims 1 to 5.

7. Multiple speakers are mounted on the mobile body. The output unit dynamically switches between the multiple speakers that output the sound signal that has undergone the predetermined processing. A sound output device according to any one of claims 1 to 6.

8. A mobile vehicle that moves with a user on board, A rotating body that generates rotational driving force, A sound output device according to any one of claims 1 to 7, comprising a sound output device that outputs a sound signal indicating a sound for emphasizing the rotating body sound emitted from the rotating body, The system comprises a speaker to which the sound signal from the sound output device is input. A mobile object.

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