JP4635931B2 - Waveform generator and program - Google Patents

Description

  The present invention relates to a technique for processing and generating an engine sound waveform.

  Engine sounds often become noise for people around them, and therefore, engines and vehicles that do not emit engine noise as much as possible have been developed. However, in many cases, for the driver of the vehicle, the engine sound enhances the joy of driving, and at the same time is information that plays an important role such as warning that the speed is excessive.

Therefore, there is a demand for a technique for reducing the engine sound scattered around and at the same time allowing the driver to hear a pleasant engine sound. As a method for solving such a problem, the engine sound picked up by the microphone arranged in the vehicle is subjected to a filter process that changes according to the envelope level of the engine sound or the running state of the vehicle, and is then arranged in the vehicle. For example, Patent Documents 1 and 2 have proposed a technique in which a driver hears a desired engine sound by generating sound from a speaker.
Japanese Patent Laid-Open No. 2005-134749 JP 2004-74994 A

  According to the techniques proposed in Patent Document 1 and Patent Document 2, the driver can hear powerful engine sound by increasing the reproduction volume of the engine sound processing device while driving the automobile. However, if the volume is increased too much, the engine sound increases in force, but at the same time, the surrounding sounds cannot be heard and it is dangerous.

  In view of the above situation, an object of the present invention is to provide a technique that enables a driver to hear powerful engine sound at a relatively low volume during driving of a vehicle.

The invention according to claim 1 is equipped with sound waveform input means for acquiring a sound waveform indicating the sound of the engine during operation, rotation data input means for acquiring rotation data indicating the rotation speed of the engine, and the engine. State data input means for obtaining state data indicating the driving state of the vehicle, reference frequency calculation means for calculating a frequency corresponding to the rotation data as a reference frequency, and a plurality of filters to be transmitted in the filter processing based on the reference frequency A transmission frequency band specifying means for specifying the frequency band of the transmission frequency band , a relationship between the rotational speed of the engine and the bandwidth of the transmission frequency band, and the driving state of the vehicle and the bandwidth of the transmission frequency band. Storage means for storing the relationship, rotation speed indicated by the rotation data acquired by the rotation data input means, and the state data input means Operating condition indicated by the condition data obtained Te, based on the storage contents stored in the storage means, and bandwidth specifying means for specifying the bandwidth of the transmission frequency band, obtained by the sound waveform input means Filtering the generated sound waveform and generating a sound waveform having only the frequency component of the transmission frequency band whose bandwidth is specified by the bandwidth specifying means among the frequency components of the sound waveform; and the transmission There is provided a waveform generating apparatus comprising: a distorted sound waveform generating means for generating a distorted sound waveform which is a sound waveform obtained by distorting a sound waveform generated by a filter means.

The invention according to claim 2 is characterized in that the transmission frequency band specifying means specifies, as the transmission frequency band, a frequency band whose center frequency is a frequency harmonized with the reference frequency. A waveform generation apparatus as described is provided.
The invention according to claim 3, wherein the transmission frequency band specifying unit according to claim 1 or 2, characterized in that identifying a frequency band having a central frequency multiplied by rational to said reference frequency as the transmission frequency band The waveform generating device described in 1. is provided.

Characteristics invention according to claim 4, which front Stories relationship between characteristics of the rotating speed and the distortion sound waveform generator of the engine, and, storing the relationship between the characteristics of the the driving state of the vehicle distortion sound waveform generating means A storage means, a rotation speed indicated by the rotation data acquired by the rotation data input means, an operating state indicated by the state data acquired by the state data input means, and a storage content stored in the characteristic storage means The waveform generating apparatus according to claim 1, further comprising: a characteristic specifying unit that specifies a characteristic of the distorted sound waveform generating unit.

The invention according to claim 5 distributes the distorted sound waveform generated by the distorted sound waveform generating means to a plurality of channels according to a panning ratio determined according to the position of the sound waveform input means in the vehicle. providing waveform generator according to any one of claims 1 to 4, characterized in that it comprises distribution means.

According to a sixth aspect of the present invention, there is provided a computer for acquiring a sound waveform indicating a sound of an operating engine, a process for acquiring rotation data indicating a rotation speed of the engine, and a vehicle on which the engine is mounted. A process for obtaining state data indicating an operation state, a process for calculating a frequency corresponding to the rotation data as a reference frequency, and a plurality of frequency bands to be transmitted in the filtering process based on the reference frequency as a transmission frequency band Processing to store the relationship between the rotational speed of the engine and the bandwidth of the transmission frequency band, and the relationship between the driving state of the vehicle and the bandwidth of the transmission frequency band in the storage means, and the acquisition Based on the rotation speed indicated by the rotation data obtained, the operation state indicated by the acquired state data, and the stored contents stored in the storage means. A process of specifying the bandwidth of the frequency band, and filtering the acquired sound waveform, and generates a sound waveform having only the frequency components of the transmitted frequency band the bandwidth is identified among the frequency components of the sound waveform There is provided a program for executing processing and processing for generating a distorted sound waveform that is a sound waveform obtained by distorting a sound waveform generated by the filtering.

[1. Embodiment]
[1.1. Constitution]
FIG. 1 is a block diagram showing a configuration of a waveform generation system 1 including a waveform generation apparatus 10 according to an embodiment of the present invention. The waveform generation system 1 is arranged in an engine room and a vehicle of a vehicle driven by an engine. In the following description, as an example, it is assumed that the waveform generation system 1 is arranged in an automobile equipped with a four-cylinder four-stroke engine.

  The waveform generation system 1 includes a waveform generation device 10 that processes engine sound to generate a distorted engine sound, a cylinder sound pickup group 11 that outputs a waveform signal of a sound accompanying an engine explosion to the waveform generation device 10, Mixers 12A to 12C for mixing the waveform signals output from the pickups included in the cylinder sound pickup group 11 for each pickup type, and the mechanical noise pickup groups 13 for outputting the waveform of the mechanical noise accompanying the operation of the engine to the waveform generation device 10. A rotation speed sensor 14 that measures the rotation speed of the crankshaft of the engine and outputs a signal indicating the result (hereinafter referred to as “rotation speed signal”) to the waveform generation apparatus 10, and an accelerator pedal for the waveform generation apparatus 10. Accelerator position sensor that outputs a signal indicating the degree of depression (hereinafter referred to as "accelerator position signal") And a support 15.

  Further, the waveform generation system 1 includes an amplifier 16 that amplifies the sound waveform synthesized by the waveform generation device 10, a speaker 17 that converts the sound waveform output from the amplifier 16 into sound, and a user's response to the waveform generation device 10. An input device 18 that outputs a signal corresponding to the operation and a display 19 that displays a message screen to the user according to the drawing data output from the waveform generation apparatus 10 are provided.

  The cylinder sound pickup group 11 includes intake sound pickups 111-1 to 111-4 that are piezoelectric sensors respectively disposed on the surfaces of the first to fourth intake pipes that supply fuel gas to the first to fourth cylinders of the engine. And explosion sound pickups 112-1 to 112-4, which are piezoelectric sensors respectively disposed on the surfaces of the cylinders of the first to fourth cylinders, and first to first exhaust gases discharged from the cylinders of the first to fourth cylinders. Exhaust sound pickups 113-1 to 113-4, which are piezoelectric sensors respectively disposed on the surface of the fourth exhaust pipe, are included.

  The signals output from the intake sound pickups 111-1 to 111-4 are waveform signals indicating the vibrations of the first to fourth intake pipes, respectively, and mainly indicate the intake sound associated with the operation of the first to fourth cylinders. Similarly, the signals output from the explosion sound pickups 112-1 to 112-4 are waveform signals indicating the vibrations of the first to fourth cylinders, respectively, and mainly indicate the explosion sounds associated with the operation of the first to fourth cylinders. . The signals output from the exhaust sound pickups 113-1 to 113-4 are waveform signals indicating the vibrations of the first to fourth exhaust pipes, respectively, and mainly indicate the exhaust sound accompanying the operation of the first to fourth cylinders. .

  The mixer 12A is a mixer that mixes waveform signals output from each of the intake sound pickups 111-1 to 111-4. The mixer 12B is a mixer that mixes waveform signals output from each of the explosion sound pickups 112-1 to 112-4. The mixer 12C is a mixer that mixes waveform signals output from the exhaust sound pickups 113-1 to 113-4.

  The mechanical noise pickup group 13 includes a cam chain sound pickup 131 that is a piezoelectric sensor arranged on the surface of a gear that drives the cam chain, and a fan belt sound pickup 132 that is a piezoelectric sensor arranged on the surface of the fan belt tensioner. include.

  The signal output from the cam chain sound pickup 131 mainly indicates mechanical noise accompanying the rotation of the cam chain. The signal output from the fan belt sound pickup 132 mainly indicates mechanical noise accompanying the rotation of the fan belt. Note that the cam chain sound pickup 131 and the fan belt sound pickup 132 are examples of pickups included in the mechanical noise pickup group 13, and pickups that are arranged at other sites are provided as long as they pick up mechanical noises that are generated during engine operation. May be included in the mechanical noise pickup group 13.

  The rotation speed sensor 14 is composed of a light emitter, an optical sensor, a counter, and a timer disposed near the crankshaft, and light emitted from the light emitter to the crankshaft is reflected by a reflection mark attached to a predetermined position of the crankshaft. Then, the counter counts the number of times the reflected light is received by the optical sensor, outputs a signal indicating the number of times stored in the counter at the timing when one second is counted by the timer, and sets the counter value to zero. And reset the timer. The output signal is a rotation speed signal indicating the rotation speed of the crankshaft at the number of rotations per second.

  The accelerator opening sensor 15 is configured by, for example, a combination of a plurality of light emitters and light sensors, and utilizes the fact that light emitted from the light emitter by the accelerator pedal is blocked by the accelerator pedal, and any of the light sensors emits reflected light. It is a mechanism that measures the degree of depression of the accelerator pedal depending on whether light is received. In the following description, it is assumed that the accelerator opening sensor 15 outputs an accelerator opening signal indicating a larger value as the degree of depression of the accelerator pedal increases, and the range thereof is 0-100.

  The accelerator opening sensor 15 is an example of a sensor that measures the driving state of the automobile, and the waveform generation system 1 includes other types of sensors, and these sensors are added to the accelerator opening sensor 15, or It may be used instead of the accelerator opening sensor 15. As such a sensor, for example, a vehicle speed sensor, a torque sensor for measuring the torque of the crankshaft, and the like can be considered.

  The speaker 17 is, for example, a combination of a speaker 17R and a speaker 17L disposed on the left and right sides of the front part of the vehicle. In addition, the arrangement position of the speaker 17 is not limited to this, and for example, the speaker 17 may be arranged at two positions in the front-rear position in the vehicle or at four positions on the front-rear, left-right. The amplifier 16 is a combination of an amplifier 16R and an amplifier 16L that output a sound signal to each of the speaker 17R and the speaker 17L.

  The input device 18 and the display 19 are integrated as a liquid crystal display with a touch sensor function, for example, and are arranged on an instrument panel in the vehicle.

  The waveform generator 10 includes a sound wave input bus 101 that is a bus for receiving sound wave signals output from the pickups and mixers 12A to 12C included in the cylinder sound pickup group 11, a rotation speed sensor 14, and an accelerator opening sensor. The sensor signal input bus 102 which is a bus for receiving the sensor signal output from each of 15 and the sound wave signals output from the pickups and mixers 12A to 12C included in the cylinder sound pickup group 11 are distorted. Distortion filters 103A to 103E, which are filters for generating sound wave signals, and a mixer 104 that pans and mixes the sound wave signals output from each of the distortion filters 103A to 103E into two left and right channels.

  Further, the waveform generation device 10 outputs distortion sound waves 103R to 103L, which are filters that generate sound wave signals that are distorted using the left and right channel sound wave signals output from the mixer 104, and output from the distortion filters 103R to 103L. Transmission characteristics simulation filters 105R to 105L, which are filters that reflect changes in frequency characteristics accompanying sound transmission from the engine room to the vehicle interior, and the accelerator position signal output from the accelerator position sensor 15. Correspondingly, dynamic filters 106R to 106L are provided which respectively apply filter processing whose parameters change continuously to the sound wave signals output from the transfer characteristic simulation filters 105R to 105L.

  The waveform generation apparatus 10 stores in advance parameters for filter processing performed by the transfer characteristic simulation filter 105 and the dynamic filter 106, screen definition data for defining a user interface screen, and the like. A storage unit 107 that temporarily stores various data to be used; a screen generation unit 108 that generates drawing data indicating a user interface screen and the like based on the screen definition data stored in the storage unit 107 and outputs the drawing data to the display 19; A parameter input unit 109 for specifying various parameters input by the user based on a signal received from the input device 18 is provided.

  The distortion filters 103A to 103E and R to L all have the same configuration and function. Therefore, hereinafter, when it is not necessary to distinguish between them, they are simply referred to as a distortion filter 103. FIG. 2 is a block diagram showing the configuration of the distortion filter 103.

  The distortion filter 103 is based on the reference frequency calculated by the reference frequency calculation unit 1031 and the reference frequency calculation unit 1031 which calculates the fundamental frequency of the engine sound based on the rotation speed signal output from the rotation speed sensor 14 as a reference frequency. A transmission frequency band specifying unit 1032 that specifies a frequency band to be transmitted as a transmission frequency band, and a transmission frequency band among frequency components of a sound waveform signal received from another component (for example, mixer 12A in the case of distortion filter 103A) A transmission filter unit 1033 that generates a sound waveform signal having only frequency components in the frequency band specified by the specification unit 1032, and a distorted sound wave that indicates a sound waveform distorted by distorting the sound waveform signal generated by the transmission filter unit 1033 A distorted sound waveform generator 1034 for generating a shape signal is provided.

  The distorted sound waveform signal generated by the distorted sound waveform generator 1034 is sequentially output to another component (for example, the mixer 104 in the case of the distortion filter 103A).

[1.2. Operation]
Next, the operation of the waveform generation system 1 will be described. When the user performs an activation operation of the waveform generation device 10, the screen generation unit 108 of the waveform generation device 10 reads the screen definition data of the user interface from the storage unit 107, generates screen drawing data, and outputs it to the display 19. To do. As a result, a user interface screen is displayed on the display 19.

  FIG. 3 is a diagram illustrating a user interface screen displayed on the display 19. The user interface screen is a screen for inputting various parameters relating to processing of the distortion filters 103A to 103E and RL. In the list box 181 included in the user interface screen, the user selects “intake sound”, “explosion sound”, “exhaust sound”, “cam chain sound”, “fan belt sound”, “right sound”, “left sound”. By selecting one of the options from “”, it is selected which parameter relating to which sound is to be input. These options correspond to the distortion filters 103A-E and R-L, respectively.

  Subsequently, in the list box 182 included in the user interface screen, the user selects one of the choices such as “distortion”, “overdrive”, “fuzz”, “crunch”, and the like in the list box 181. For the sound, it is selected which of the so-called distortion systems to generate the distorted sound waveform signal.

In addition, the user selects one or more keys in the object group 183 indicating a virtual keyboard, thereby designating the center frequency of the frequency band of the frequency component to be used for generating the distorted sound waveform signal. . Here, the left C key in the object group 183 corresponds to the frequency of the fundamental sound of the engine sound. Hereinafter, this key is set as “C ₅ ”, and the subscripts are increased as “C ₆ ” and “C ₇ ” as the value increases by one octave. The same applies to keys other than “C”. For example, the key “E ₅ ” right next to “C ₅ ” is the key “E ₅ ”, and corresponds to a frequency that is (5/4) times the fundamental tone of the engine sound.

  In addition, in the list box 184, the user selects one of the options of “rotational speed” and “accelerator opening” to input a parameter change corresponding to either the rotational speed signal or the accelerator opening signal. Is specified.

When the user performs input in list box 181 to list box 184 and object group 183, an envelope group corresponding to the input information is displayed on the user interface screen. The user can input various parameters that change according to the rotational speed or the accelerator opening by changing the shape of the envelope group. Hereinafter, in the list box 181 to the list box 184, “intake sound”, “overdrive”, and “accelerator opening” are selected by the user, and “C ₅ ”, “F ₅ ”, and “G ₆ ” are selected in the object group 183. Assume that it is selected.

The object group 185 expands the bandwidth of the frequency band whose center frequency is the frequency corresponding to “C ₅ ”, “F ₅ ”, and “G ₆ ” selected in the object group 183 according to the accelerator opening. An envelope group for specifying The object group 186 amplifies the sound in the frequency band centered on the frequency corresponding to “C ₅ ”, “F ₅ ”, and “G ₆ ” selected in the object group 183 according to the accelerator opening. An envelope group for specifying

  The object group 187 is an envelope group for designating how much a sound waveform signal (hereinafter referred to as “input sound waveform signal”) input to the distortion filter 103 is amplified according to the accelerator opening. . The object group 188 is an envelope group for designating how much the low frequency band component of the input sound waveform signal is amplified according to the accelerator opening. Similarly, the object group 189 and the object group 190 are envelope groups for designating how much the components in the medium frequency band and high frequency band of the input sound waveform signal are amplified according to the accelerator opening.

  The object group 191 is an envelope group for designating how to change the degree of distortion of the distorted sound waveform signal generated from the input sound waveform signal in accordance with the accelerator opening. The object group 192 is an envelope for designating how much the sound wave signal before being output from the distortion filter 103 (hereinafter referred to as “output sound wave signal”) is amplified according to the accelerator opening. A group.

  The user sequentially changes the choices in the list box 181 to the list box 184, and repeats selection of the pitch in the object group 183 and change of the envelope in the object group 186 to the object group 192.・ For each of the above, which effector is used, which frequency band sound is transmitted, input / output level to the effector and various parameters of the effector according to changes in the rotational speed and accelerator opening Enter how to change.

  When various parameters are input by the user as described above, the waveform generation apparatus 10 receives signals corresponding to the user's operation from the input device 18 and indicates those parameters received by the parameter input unit 109 as various parameters. The data is converted into parameter data and stored in the storage unit 107 as the attribute value of the corresponding object in the screen definition data on the user interface screen.

  When the user completes the input of the various parameters described above, the user operates the command button 193 to instruct the waveform generation device 10 to generate and reproduce the engine sound. In response to the user's instruction, the distortion filters 103A to 103E and R to L each generate a distortion sound waveform signal using input sound waveform signals that are sequentially input, and output the generated distortion sound waveform signal as an output sound waveform. The process of sequentially outputting as signals is started. Since the operations of the distortion filters 103A to 103E and R to L are the same, processing performed by the distortion filter 103 will be described below using the distortion filter 103A as an example.

  The reference frequency calculation unit 1031 of the distortion filter 103A receives a rotation speed signal from the rotation speed sensor 14 every time the crankshaft makes one rotation. When the reference frequency calculation unit 1031 receives the rotation speed signal, the reference frequency calculation unit 1031 calculates f (Hz) represented by f = r / 2 using the rotation speed r (rotation / second) indicated by the rotation speed signal as a reference frequency. . F calculated in this way is the frequency of the fundamental sound of the engine sound. Here, the reason for calculating the frequency f (Hz) by dividing r (rotation / second) by 2 is “intake”, “compression”, “explosion”, “exhaust” associated with one explosion in a 4-stroke engine. This is because the crankshaft rotates twice in one cycle of four steps.

  Accordingly, when the waveform generation system 1 is used in a vehicle equipped with a two-stroke engine, the reference frequency calculation unit 1031 uses f (Hz) represented by f (Hz) = r (rotation / second) as the engine. Calculated as the fundamental frequency of the sound. This is because in the two-stroke engine, the crankshaft makes one rotation in one cycle.

The reference frequency calculation unit 1031 outputs a signal indicating the reference frequency f (Hz) calculated as described above to the transmission frequency band specifying unit 1032. When the transmission frequency band specifying unit 1032 receives a signal from the reference frequency calculation unit 1031, the pitch input by the user in the object group 183 when the reference frequency f (Hz) indicated by the signal is set to the pitch of the C sound. The frequency corresponding to is specified. More specifically, in the transmission frequency band specifying unit 1032, “C ₅ ”, “F ₅ ”, and “G ₆ ” are selected by the user based on the data stored as the attribute values of the object group 183 in the storage unit 107. F (Hz) as a frequency corresponding to “C ₅ ”, f × (4/3) (Hz) as a frequency corresponding to “F ₅ ”, and fx as a frequency corresponding to “G ₆ ”. 3 (Hz) is calculated.

Note that when the transmission frequency band specifying unit 1032 calculates the frequencies corresponding to “F ₅ ” and “G ₆ ” as described above, f is multiplied by a rational number such as “4/3” or “3”. This is because the frequency ratio between “C ₅ ” and “F ₅ ” is about 3: 4, and the frequency ratio between “C ₅ ” and “G ₆ ” is about 1: 3. In this way, the relationship between the frequencies of two sounds on the scale is often a simple integer ratio, and the ratio is as simple as 1: 2 (1 octave) or 2: 3 (perfect 5 degrees). Some have good rhythmic harmony.

The transmission frequency band specifying unit 1032 calculates the frequency as described above, and receives a rotation speed signal from the rotation speed sensor 14 every time the crankshaft makes one rotation. Further, the transmission frequency band specifying unit 1032 receives an accelerator opening signal from the accelerator opening sensor 15 at a sufficiently short predetermined time interval, for example. When the transmission frequency band specifying unit 1032 calculates the frequencies corresponding to “C ₅ ”, “F ₅ ”, and “G ₆ ” as described above, the rotation speed signal and the accelerator opening signal that are received last and the user list Based on the envelope input in the object group 185 after selecting each of “rotational speed” and “accelerator opening” in the box 184, the frequency band (transmission frequency band) to be transmitted in the transmission filter unit 1033 is specified.

Therefore, first, the transmission frequency band specifying unit 1032 specifies the bandwidth of the transmission frequency band. More specifically, for example, the accelerator opening signal received last by the transmission frequency band specifying unit 1032 is “35”, and the user selects “accelerator opening” in the list box 184 and designates it in the object group 185. The magnitude of the bandwidth corresponding to the accelerator opening “35” of the envelope corresponding to “C ₅ ” is “7”, and the rotation speed signal last received by the transmission frequency band specifying unit 1032 is “50”. When the user selects “rotation speed” in the list box 184 and the bandwidth corresponding to the rotation speed “50” of the envelope corresponding to “C ₅ ” designated in the object group 185 is “4”, the transmission is performed. The frequency band specifying unit 1032 calculates “5.5” as an average value of “7” and “4”.

Subsequently, the transmission frequency band specifying unit 1032 uses the frequency f (Hz) corresponding to “C ₅ ” and the calculated average value “5.5” to use the frequency f (Hz) as the center frequency f ^ (1 The frequency band of −5.5 / 1000) (Hz) to f ^ (1 + 5.5 / 1000) (Hz) is specified. However, “^” represents a power. Similarly, the transmission frequency band specifying unit 1032 specifies frequency bands corresponding to “F ₅ ” and “G ₆ ”.

As described above, the frequency band specified by the transmission frequency band specifying unit 1032 has the frequency calculated by the reference frequency calculating unit 1031 as the center frequency, and the rotation speed and accelerator opening according to the envelope specified by the user in the object group 186. It is a frequency band having a bandwidth determined according to. The transmission frequency band specifying unit 1032 specifies the frequency bands specified as described above as transmission frequency bands corresponding to “C ₅ ”, “F ₅ ”, and “G ₆ ”, respectively, and their pitches (“C ₅ ”) and the transmission frequency band (hereinafter referred to as“ transmission frequency band signal ”) is output to the transmission filter unit 1033.

  Similar to the transmission frequency band specifying unit 1032, the transmission filter unit 1033 continuously receives the rotation speed signal and the accelerator opening signal from the rotation speed sensor 14 and the accelerator opening sensor 15. When the transmission filter unit 1033 receives the transmission frequency band signal from the transmission frequency band specifying unit 1032, the envelope input in the object group 186 after the user selects each of “rotational speed” and “accelerator opening” in the list box 184. Based on the above, it is specified at what amplification rate the component in the frequency band indicated by the transmission frequency band signal is transmitted.

More specifically, for example, the accelerator opening signal received last by the transmission filter unit 1033 is “35”, and the user selects “accelerator opening” in the list box 184 and designates “C” specified in the object group 186. _The amplification factor corresponding to the accelerator opening “35” of the envelope corresponding to “ ₅ ” is “0.5”, the rotation speed signal last received by the transmission filter unit 1033 is “50”, and the user makes a list box When the “rotation speed” is selected in 184 and the amplification factor corresponding to the rotation speed “50” of the envelope corresponding to “C ₅ ” designated in the object group 186 is “0.3”, the transmission filter unit 1033 “0.4” is calculated as an average value of “0.5” and “0.3”. The value calculated in this way is an amplification factor (hereinafter referred to as “transmission amplification factor”) of the frequency component that is transmitted in the transmission frequency band corresponding to “C ₅ ”. Similarly, the transmission filter unit 1033 identifies transmission amplification factors corresponding to “F ₅ ” and “G ₆ ”.

  While the transmission filter unit 1033 specifies the transmission amplification factor as described above, the transmission filter unit 1033 indicates the sound obtained by mixing the intake sound corresponding to each of the first to fourth cylinders from the mixer 12A via the sound waveform input bus 101. The input sound waveform signal is constantly received. When the transmission filter unit 1033 identifies the transmission amplification factor, it extracts only the component of the transmission frequency band indicated by the transmission frequency band signal from the frequency components of the input sound waveform signal, and the extracted component is determined according to each transmission frequency band. Amplify with transmission gain.

  FIG. 4 is a diagram schematically illustrating processing performed by the transmission filter unit 1033. FIG. 4A is a graph showing the frequency characteristics of the input sound waveform signal. FIG. 4B is a graph showing the filter characteristics of the transmission filter unit 1033. The transmission filter unit 1033 multiplies the amplitude of each frequency of the input sound waveform signal shown in FIG. 4A by the amplification factor of each frequency shown in FIG. The sound waveform signal shown in FIG. The transmission filter unit 1033 sequentially outputs the sound wave signal thus generated (hereinafter referred to as “transmission sound wave signal”) to the distorted sound wave generation unit 1034.

  Similar to the transmission frequency band specifying unit 1032 and the transmission filter unit 1033, the distorted sound waveform generation unit 1034 continuously receives the rotation speed signal and the accelerator opening signal from the rotation speed sensor 14 and the accelerator opening sensor 15. When the distorted sound waveform generation unit 1034 receives these signals, the user selects each of “rotation speed” and “accelerator opening” in the list box 184 and then based on the envelopes input in the object group 187 to the object group 191. The parameter of the distortion effector selected by the user in the list box 182 is specified.

  More specifically, for example, the accelerator opening signal received last by the distorted sound waveform generator 1034 is “35”, and the user selects “accelerator opening” in the list box 184 and designates it in the object group 187. The gain corresponding to the accelerator opening “35” of the envelope is “+10”, the rotational speed signal last received by the distorted sound waveform generator 1034 is “50”, and the user selects “rotational speed” in the list box 184. When the gain corresponding to the rotational speed “50” of the envelope designated in the object group 187 is “+8”, the distorted sound waveform generator 1034 displays the average value “+9”, and the user selects the list box 182. Is specified as the input level parameter of the effector “overdrive” selected in.

  Similarly, the distorted sound waveform generating unit 1034 identifies the low frequency band gain, medium frequency band gain, high frequency band gain, distortion level, and output level parameters of the effector. The distorted sound waveform generating unit 1034 generates a distorted sound waveform signal that is a signal obtained by distorting the transmitted sound waveform signal received from the transmission filter unit 1033 according to the specified parameters. The distorted sound waveform generator 1034 outputs the generated distorted sound waveform signal to the mixer 104 as an output sound waveform signal.

  As described above, the distortion filter 103 </ b> A distorts the sound waveform signal received from the mixer 12 </ b> A to generate a distortion sound waveform signal of the intake sound and outputs it to the mixer 104. The distortion filters 103B to 103E perform processing similar to that of the distortion filter 103A on the sound wave signals received from the mixers 12B to 12C, the cam chain sound pickup 131 and the fan belt sound pickup 132, respectively, and generate explosion sounds, exhaust sounds and cam chain sounds. Then, a distortion sound waveform signal of fan belt sound is generated and output to the mixer 104.

  The mixer 104 performs a predetermined panning process on the distorted sound waveform signals received from each of the distortion filters 103A to 103E, and distributes them to the left and right channels to mix them. The panning ratio is determined, for example, depending on how far each of the intake sound pickup 111 to fan belt sound pickup 132 is displaced from the center position in the left-right direction of the automobile.

  The mixer 104 sequentially outputs the right channel sound waveform signal and the left channel sound waveform signal generated by mixing to the distortion filters 103R and L, respectively. When the distortion filters 103R and L receive the sound waveform signals from the mixer 104, the distortion filters 103R and L perform the same processing as the distortion filter 103A on them to generate distortion sound waveform signals for the right sound and the left sound, and transfer characteristic simulation filters 105R and 105R. Deliver to L.

  The transfer characteristic simulation filters 105R and L input the sound waveform signals received from the distortion filters 103R and L to a predetermined transfer function, and thereby the frequency generated until the sound generated in the engine room reaches the driver's ear in the vehicle. The change in characteristics is reflected in the sound signal waveform received from the distortion filters 103R and 103L.

  More specifically, a coefficient sequence of a transfer function calculated based on an impulse response at the driver's head position in the vehicle with respect to an impulse signal generated at, for example, the center position of the engine room is stored in the storage unit 107 in advance. . The transfer characteristic simulation filter 105 is a coefficient obtained by, for example, multiplying each coefficient sequence obtained by Fourier transforming the sound signal waveforms received from the distortion filters 103R and L by each coefficient sequence of the stored transfer function. Inverse Fourier transform the sequence. The transfer characteristic simulation filters 105R and L output the sound signal waveforms thus generated to the dynamic filters 106R and L, respectively.

  The dynamic filters 106R and L always receive the accelerator opening signal from the accelerator opening sensor 15, and perform filter processing corresponding to the received accelerator opening signal on the sound signal waveform received from the transfer characteristic simulation filters 105R and L. . The filter process performed by the dynamic filters 106R and L is, for example, a graphic equalizer process. For the processing of the dynamic filter 106, the storage unit 107 stores in advance correspondence data between the accelerator opening and the amplification factor for each frequency band of the graphic equalizer.

  FIG. 5 is a graph showing the correspondence data stored in the storage unit 107. In the case of following the data example of FIG. 5, when the accelerator opening signal indicates “90”, the dynamic filter 106 increases the amplitude of the frequency band of the center frequency 63 Hz, 125 Hz,. Amplify to double. The dynamic filters 106R and L output the sound waveform signals subjected to such filter processing to the amplifiers 16R and L, respectively.

  When the amplifiers 16R and L receive the sound signal waveforms from the dynamic filters 106R and L of the waveform generation device 10 as described above, the amplifiers 16R and L amplify the received sound waveform signals to the speaker level and output them to the speakers 17R and L, respectively. . The speakers 17R and L convert the sound waveform signals received from the amplifiers 16R and L into sound and generate sound. As a result, the driver can hear the engine sound generated by the waveform generator 10.

  The engine sound that can be heard by the driver as described above is a frequency band that is selectively transmitted according to various parameters input by the user on the user interface screen (see FIG. 3) among the frequency components included in the actual engine sound. The component is added with distortion. In addition, such a selectively transmitted frequency band is centered on a frequency having a rhythmic relationship with the fundamental frequency of the engine sound. Therefore, the engine sound that can be heard by the driver is not a noisy noise, but a harmoniously harmonious and pleasant sounding distortion sound.

  In particular, when the user selects a small number of intervals such as about 2 to 3 in the object group 183 and the intervals of those intervals are harmoniously harmonized such as 5 degrees, the waveform generation system 1 emits. Distorted sound is preferable.

  Furthermore, the engine sound generated by the waveform generation system 1 changes according to the operating state such as the engine speed and the accelerator opening. The quality and degree of the change can be changed by the user in various ways.

  In the present embodiment, since the waveform signal indicating the sound emitted from each part of the engine is individually acquired and the distortion filter 103 is processed according to different parameters for each of them, the user generates the waveform generation system 1. The engine sound generated by can be finely adjusted.

[2. Modified example]
The above-described embodiment can be variously modified within the scope of the technical idea of the present invention. Such a modification is shown below.

[2.1. First Modification]
In the embodiment described above, in the mixer 12A, the waveform signals generated by the intake sound pickups 111-1 to 111-4 arranged for each cylinder of the engine are mixed and then input to the distortion filter 103A. The distortion filter 103 may be individually processed for the waveform signals generated by each of the intake sound pickups 111-1 to 111-4. The same applies to the explosion sound pickup 112 and the exhaust sound pickup 113.

[2.2. Second Modification]
In the embodiment described above, the distortion filter 103 is disposed both upstream and downstream of the mixer 104 in the flow of the sound wave signal. However, the distortion filter 103 is disposed only in one of them. May be. That is, the waveform generation device 10 may include only one of the distortion filters 103A to 103E and the distortion filters 103R to 103L.

[2.3. Third Modification]
In the above-described embodiment, the user designates the center frequency of the transmission frequency band by designating the virtual key of the object group 183. For example, the user inputs a symbol such as “F4” indicating the pitch. Alternatively, the center frequency of the transmission frequency band may be designated by numerically inputting a magnification with respect to the reference frequency such as “3/2”.

  As described above, the relationship between the frequencies of two sounds on the scale is often a simple integer ratio, such that the ratio is 1: 2 (1 octave) or 2: 3 (completely 5 degrees). Something that is simple is good in rhythmic harmony. Therefore, for example, when the reference frequency is f, by multiplying f by a rational number having a ratio of 1: 2 or 2: 3, a center frequency that is harmoniously harmonized with each other, such as 1 octave or 5 degrees, is calculated. be able to. In particular, by multiplying f by an integer having a ratio of 1: 2 or 2: 3, it is possible to calculate a center frequency that is in harmony with each other and is a harmonic of f. Therefore, the user can use numerical values such as “5/4” and “3/2” (a set of rational numbers that are 5: 6) and “6” and “9” (a set of integers that are 2: 3) as a reference. By specifying the magnification as a frequency, it is possible to easily obtain a distorted sound that is harmoniously harmonized.

  Instead of the user inputting the combination of the above numerical values, the user inputs only one magnification, and the transmission frequency band specifying unit 1032 multiplies the magnification input by the user by f, and the magnification is a predetermined multiple. For example, a frequency obtained by multiplying f by a factor of (3/2) may be calculated as the center frequency of the transmission frequency band. In this case, the user can specify two center frequencies having a perfect 5 degree interval by only inputting one magnification.

  Furthermore, the transmission frequency band specifying unit 1032 may calculate a center frequency that can be harmonized with each other by multiplying a predetermined magnification by f without requesting the user to specify the magnification. For example, the transmission frequency band specifying unit 1032 calculates f × 2 and f × 3 regardless of the user input, and sets them as the center frequency of the transmission frequency band. As a result, two center frequencies having a perfect 5 degree interval are identified.

In the embodiment described above, for example, when “G ₅ ” is designated by the user, the transmission frequency band specifying unit 1032 indicates “3 / G ₅ ” indicating an interval of “C ₅ ” − “G ₅ ” with respect to the reference frequency. However, the center frequency of the transmission frequency band may be calculated by multiplying the reference frequency by “1.4983”, which is a more accurate numerical value.

  Further, the user designates an arbitrary magnification without being caught by the interval between two sounds on the scale, and the transmission frequency band specifying unit 1032 multiplies the reference frequency by the designated magnification so that the center frequency of the transmission frequency band. May be calculated. In that case, the distorted sound waveform signal generated by the distorted sound waveform generator 1034 includes many non-integer overtones of the fundamental sound of the engine sound.

[2.4. Fourth Modification]
In the above-described embodiment, it is assumed that the waveform generation device 10 is realized by a combination of dedicated hardware circuits corresponding to each component, but causes a general-purpose computer to execute processing according to an application program. Thus, the waveform generation device 10 may be realized.

[3. Remarks]
The numerical values shown in the above-described embodiment and its modifications and the calculation methods of those numerical values are examples for explaining the present invention, and the technical scope of the present invention is not limited to these numerical values and calculation methods.

  Further, the order of processing in the waveform generation system 1 shown in the above-described embodiment can be changed within the scope of the technical idea of the present invention.

  A sensor other than a piezoelectric sensor may be used as the intake sound pickup 111 or the like, or a microphone that collects sound may be used. The arrangement position is not limited to that described in the embodiment, and may be in a vehicle, for example.

It is the block diagram which showed the structure of the waveform generation system concerning embodiment of this invention. It is the block diagram which showed the structure of the distortion filter concerning embodiment of this invention. It is the figure which showed the user interface screen concerning embodiment of this invention. It is the figure which showed the process of the permeation | transmission filter part concerning embodiment of this invention. It is the graph which showed the corresponding data which the dynamic filter concerning embodiment of this invention utilizes.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Waveform generation system, 10 ... Waveform generation apparatus, 11 ... Cylinder sound pickup group, 12 ... Mixer, 13 ... Mechanical noise pickup group, 14 ... Rotational speed sensor, 15 ... Accelerator opening sensor, 16 ... Amplifier, 17 ... Speaker, DESCRIPTION OF SYMBOLS 18 ... Input device, 19 ... Display, 101 ... Sound wave input bus, 102 ... Sensor signal input bus, 103 ... Distortion filter, 104 ... Mixer, 105 ... Transfer characteristic simulation filter, 106 ... Dynamic filter, 107 ... Memory | storage part, DESCRIPTION OF SYMBOLS 108 ... Screen generation part, 109 ... Parameter input part, 111 ... Intake sound pickup, 112 ... Explosive sound pickup, 113 ... Exhaust sound pickup, 131 ... Cam chain sound pickup, 132 ... Fan belt sound pickup, 1031 ... Reference frequency calculation part 1032 ... Transmission frequency band specifying part, 1033 ... Transmission Filter unit, 1034 ... distortion sound waveform generator.

Claims (6)

Sound waveform input means for acquiring a sound waveform indicating the sound of the engine during operation;
Rotation data input means for acquiring rotation data indicating the rotation speed of the engine;
State data input means for acquiring state data indicating a driving state of the vehicle on which the engine is mounted;
A reference frequency calculating means for calculating a frequency according to the rotation data as a reference frequency;
Based on the reference frequency, a transmission frequency band specifying means for specifying a plurality of frequency bands to be transmitted in the filter processing as a transmission frequency band;
Storage means for storing the relationship between the rotational speed of the engine and the bandwidth of the transmission frequency band, and the relationship between the driving state of the vehicle and the bandwidth of the transmission frequency band;
Based on the rotation speed indicated by the rotation data acquired by the rotation data input means, the operation state indicated by the state data acquired by the state data input means, and the stored contents stored in the storage means, Bandwidth specifying means for specifying the bandwidth of the transmission frequency band;
The sound waveform acquired by the sound waveform input means is filtered to generate a sound waveform having only the frequency component of the transmission frequency band whose bandwidth is specified by the bandwidth specifying means among the frequency components of the sound waveform. Transmission filter means;
A waveform generating apparatus comprising: a distorted sound waveform generating unit that generates a distorted sound waveform that is a sound waveform obtained by distorting the sound waveform generated by the transmission filter unit. The waveform generation device according to claim 1, wherein the transmission frequency band specifying unit specifies, as the transmission frequency band, a frequency band whose center frequency is a frequency harmonized with the reference frequency. The waveform generation device according to claim 1, wherein the transmission frequency band specifying unit specifies, as the transmission frequency band, a frequency band having a frequency obtained by multiplying the reference frequency by a rational number as a center frequency. Relationship between characteristics of the rotating speed and the distortion sound waveform generating means before SL engine, and, a characteristic storage means for storing a relationship between the characteristics of the driving state of the vehicle the distortion sound waveform generating means,
Based on the rotation speed indicated by the rotation data acquired by the rotation data input means, the operating state indicated by the state data acquired by the state data input means, and the stored contents stored in the characteristic storage means, The waveform generating apparatus according to claim 1, further comprising: a characteristic specifying unit that specifies a characteristic of the distorted sound waveform generating unit. Distributing means for allocating the distorted sound waveform generated by the distorted sound waveform generating means to a plurality of channels according to a panning ratio determined according to the position of the sound waveform input means in the vehicle. The waveform generation device according to any one of claims 1 to 4 . On the computer,
Processing to obtain a sound waveform indicating the sound of the engine during operation;
Processing for obtaining rotation data indicating the rotation speed of the engine;
Processing for obtaining state data indicating a driving state of a vehicle on which the engine is mounted;
Processing to calculate a frequency according to the rotation data as a reference frequency;
Based on the reference frequency, a process of specifying a plurality of frequency bands to be transmitted in the filter process as a transmission frequency band;
A process of storing a relationship between a rotational speed of the engine and a bandwidth of the transmission frequency band, and a relationship between a driving state of the vehicle and a bandwidth of the transmission frequency band in a storage unit;
A process of specifying the bandwidth of the transmission frequency band based on the rotation speed indicated by the acquired rotation data, the operation state indicated by the acquired state data, and the storage content stored in the storage means When,
Filtering the acquired sound waveform to generate a sound waveform having only the frequency component of the transmission frequency band in which the bandwidth is specified among the frequency components of the sound waveform;
A program for generating a distorted sound waveform that is a sound waveform obtained by distorting the sound waveform generated by the filtering.

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