JP2021103869A - Sound producing device - Google Patents

Abstract

To suppress deterioration of noise level estimation accuracy due to a temperature change of a speaker.SOLUTION: A sound producing device includes: a filter 251 for attenuating a specified block band corresponding to a peak frequency of an electromotive force signal to be output from a speaker 3; a noise level estimation section 253 for estimating a noise level of sound collected by the speaker 3 based on an electromotive force signal that has passed through the filter 251; a temperature estimation section 26 for estimating sound producing body temperature being the temperature of the speaker 3; and a band control section 254 for changing a specified block band of the filter 251 with the use of sound producing body temperature estimated by the temperature estimation section 26.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sounding device.

Conventionally, there is a device mounted on a vehicle to emit sound from a speaker toward the periphery of the vehicle. For example, Patent Document 1 describes a vehicle approach notification device that notifies the approach of a vehicle to the surroundings of the vehicle by generating an approach notification sound from a speaker. This device estimates the temperature of the speaker and corrects the sound pressure level of the approach notification sound based on the estimated temperature to correct the temperature of the sound pressure of the approach notification sound emitted from the speaker.

JP-A-2017-95060

In such a device, a dedicated microphone for collecting ambient noise is provided, the ambient noise level is estimated using this microphone, and the volume of sound emitted from the speaker is adjusted according to this noise level. Conceivable.

For example, when the ambient noise level is low, the volume of the sound output from the speaker is reduced, and when the ambient noise level is high, the volume of the sound output from the speaker is increased. This makes it possible to output a sound with a volume suitable for the surrounding conditions.

However, in such a configuration provided with a dedicated microphone for collecting ambient noise, there is a problem that the cost increases because the microphone is required. In addition, there is a problem that the physique of the product becomes large because a space for installing the microphone is required.

Therefore, the present inventors have focused on the fact that the speaker can function as a microphone as well as a sounding function that outputs voice, and considered that the speaker functions as a microphone to collect ambient noise.

However, it was found that the frequency characteristics of the electromotive force signal output from the speaker were not good when the speaker for sound generation was made to function as a microphone. For example, it was found that the peak frequency of the electromotive force signal output from the speaker is large, and the peak frequency of the electromotive force signal changes. It is considered that this is because the peak frequency of the impedance of the voice coil changes due to the temperature change of the speaker.

As described above, when the peak frequency of the electromotive force signal output from the speaker changes, the accuracy of estimating the noise level of the ambient sound deteriorates.

The present invention has been made in view of the above points, and an object of the present invention is to suppress a decrease in the estimation accuracy of the noise level due to a temperature change of the speaker.

In order to achieve the above object, the invention according to claim 1 emits a notification sound from a sounding body (3) having a sounding function for producing a sound and a sound collecting function for outputting an electromotive force signal corresponding to the collected sound. A sounding device that sounds, a filter (251) that attenuates a specific blocking band corresponding to the peak frequency of the electromotive force signal output from the sounding body, and a sounding body that collects the sound based on the electromotive force signal that has passed through the filter. A noise level estimation unit (253) that estimates the noise level of the sound, and a volume adjustment unit (21) that adjusts the volume of the notification sound emitted from the sounding body according to the noise level of the sound estimated by the noise level estimation unit. , 27), a temperature estimation unit (26) that estimates the sounding body temperature, which is the temperature of the sounding body, and a band control unit that changes a specific blocking band of the filter using the sounding body temperature estimated by the temperature estimation unit. (254) and.

According to such a configuration, the sounding body temperature, which is the temperature of the sounding body, is estimated by the temperature estimation unit, and the specific blocking band of the filter is changed by using the sounding body temperature estimated by the temperature estimation unit. It is possible to suppress a decrease in the estimation accuracy of the noise level due to a temperature change of the speaker.

Further, in the invention according to claim 2, the band control unit identifies the peak frequency of the electromotive force signal based on the sounding body temperature estimated by the temperature estimation unit, and filters the band control unit so as to correspond to the peak frequency of the electromotive force signal. Change the specific blocking band of.

In this way, the peak frequency of the electromotive force signal can be specified based on the temperature of the sounding body, and the specific blocking band of the filter can be changed so as to correspond to the peak frequency of the electromotive force signal.

Further, the invention according to claim 3 includes a storage unit (255) for storing frequency data obtained by individually measuring the peak frequency of the electromotive force signal output from the sounding body at a predetermined temperature, and the band control unit is a storage unit. Using the frequency data stored in, the specific blocking band of the filter is changed to correct the individual variation of the sounding body.

Therefore, it is possible to suppress a decrease in the estimation accuracy of the noise level due to individual variations of the sounding body.

The reference reference numerals in parentheses attached to each component or the like indicate an example of the correspondence between the component or the like and the specific component or the like described in the embodiment described later.

It is a figure which showed the whole structure of the sounding apparatus of 1st Embodiment. It is a figure which showed the relationship between the peak frequency and the temperature of the electromotive force signal when the speaker was made to function as a microphone. It shows the frequency characteristics of the electromotive force signal when the speaker functions as a microphone. It is a figure which showed the frequency characteristic of a filter. It is a figure which showed the frequency characteristic of the electromotive force signal which passed through a filter. It is a flowchart of the band control unit 254. It is a figure showing how the peak frequency of an electromotive force signal and the blocking band of a filter change by a temperature change. It is a flowchart of the volume adjustment process by a volume adjustment part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, the same or equal parts are designated by the same reference numerals, and the description thereof will be omitted.

(First Embodiment)
The sounding apparatus according to the first embodiment will be described with reference to FIGS. 1 to 8. The sounding device 2 is mounted on the vehicle and emits a notification sound to the surroundings of the vehicle. The sounding device 2 emits a notification sound from a speaker 3 having a sounding function for sounding and a sound collecting function for outputting an electromotive force signal corresponding to the collected sound. Examples of the notification sound include a lock notification sound output when the vehicle door is locked or unlocked, a half-door notification sound for notifying the user that the vehicle door is in the half-door state, and the like. The speaker 3 of the present embodiment is provided in a portion exposed to the outside air, such as in the engine room of a vehicle.

The sounding device 2 is composed of an ECU. A vehicle speed sensor 10, a liquid temperature sensor 11, an outside air temperature sensor 12, an engine ECU 13, and a speaker 3 are connected to the sounding device 2.

The vehicle speed sensor 10 outputs a vehicle speed detection signal of the vehicle and inputs it to the sounding device 2. The liquid temperature sensor 11 outputs a water temperature detection signal indicating the temperature of the radiator water or an oil temperature detection signal indicating the oil temperature of the engine oil, and inputs the signal to the sounding device 2. The liquid temperature sensor 11 may be one temperature sensor that detects either the temperature of the radiator water or the temperature of the engine oil, or two temperature sensors that separately transmit the detection results to the sounding device 2. Is also good. The outside air temperature sensor 12 outputs an outside air temperature detection signal indicating the outside air temperature outside the vehicle interior and inputs it to the sounding device 2. The engine ECU 13 handles values of various physical quantities used for engine control, and inputs information on the engine operating time from the values to the sounding device 2.

The detection signals of the sensors 10 to 12 and the information from the engine ECU 13 are input to the sounding device 2 through, for example, an in-vehicle LAN. Further, although the form in which the detection signals of the sensors 10 to 12 are directly input to the sounding device 2 is shown here, it is handled by another electronic control device (hereinafter referred to as ECU) provided in the vehicle. The vehicle speed information and the temperature information may be input to the sounding device 2.

For example, in the meter control ECU, since the vehicle speed detection signal of the vehicle speed sensor 10 is input to acquire the vehicle speed, the vehicle speed information may be input to the sounding device 2. Further, since the engine ECU 13 acquires the temperatures of the radiator water and the engine oil based on the detection signal of the liquid temperature sensor 11, the temperature information may be input to the sounding device 2. Further, since the ECU for controlling the air conditioner of the vehicle air conditioner acquires the outside air temperature based on the detection signal of the outside air temperature sensor 12, the outside air temperature information is input to the sounding device 2. Is also good.

The speaker 3 emits a notification sound at a frequency and a sound pressure level corresponding to an audio signal input from the AMP 231 of the sounding device 2. The speaker 3 corresponds to a sounding body.

Further, the speaker 3 has a sounding function for producing a sound and a sound collecting function as a microphone. The speaker 3 collects ambient sounds and outputs an electromotive force signal corresponding to the collected sounds.

The speaker 3 has, for example, a magnet for forming a magnetic field, a voice coil arranged in the magnetic field and vibrating when a voice current flows, and a diaphragm, and the vibration of the voice coil is transmitted to the diaphragm. It can be configured by an electrokinetic speaker that emits sound waves.

The sounding device 2 includes a microcomputer 20, a power amplifier (hereinafter referred to as AMP) 231 and 232, and a switching unit 24.

The switching unit 24 switches the connection destination of the speaker 3 according to the switching signal from the sounding device 2. When the speaker 3 functions as a sounding body, the switching unit 24 connects the connection destination of the speaker 3 to the output terminal of the AMP 231. At this time, a speaker current corresponding to the audio signal from the sounding device 2 flows from the AMP 231 to the speaker 3. The sound pressure produced by the speaker 3 is determined by the magnitude of the speaker current supplied from the AMP 231.

When the speaker 3 functions as a microphone, the switching unit 24 connects the connection destination of the speaker 3 to the input terminal of the AMP 232. At this time, the AMP 232 amplifies the electromotive force signal corresponding to the sound collected by the speaker 3, and inputs the electromotive force signal to the sounding device 2.

The microcomputer 20 is configured as a computer equipped with a CPU, I / O, and the like. The microcomputer 20 has a memory unit 22, a sound control unit 21, a DA converter 281, an AD converter 282, a noise estimation processing unit 25, a temperature estimation unit 26, and an output volume determination unit 27. The sound control unit 21, the noise estimation processing unit 25, the temperature estimation unit 26, and the output volume determination unit 27 represent functional blocks to be executed by the microcomputer 20. Further, the sound generation control unit 21 and the output volume determination unit 27 correspond to the volume adjustment unit.

The memory unit 22 stores sound source data of the notification sound, various control programs, and the like. For example, notification sound data such as PCM data is stored in the memory unit 22. Further, the memory unit 22 also stores a program or the like executed by the microcomputer 20.

The sound generation control unit 21 reads the notification sound data stored in the memory unit 22 and generates a notification sound voltage waveform signal for outputting the notification sound.

The DA converter 281 converts the digital notification sound voltage waveform signal from the sound control unit 21 into an analog signal. The notification sound voltage waveform signal converted into an analog signal by the DA converter 281 is input to the input terminal of the AMP 231.

The AD converter 282 converts the analog electromotive force signal input from the AMP232 into a digital signal. The electromotive force signal converted into a digital signal by the AD converter 282 is input to the noise estimation processing unit 25.

The noise estimation processing unit 25 includes a filter 251, an integration processing unit 252, a noise level estimation unit 253, a band control unit 254, and a memory unit 255.

The filter 251 is composed of a digital filter. The filter 251 is composed of a peaking filter that attenuates a specific frequency band (blocking band) to a low level. The peaking filter has a property that the Q value is high and the blocking band is narrow.

An electromotive force signal from the speaker 3 is input to the filter 251 via the AD converter 282.

The integration processing unit 252 integrates the electromotive force signal that has passed through the filter 251. The integration processing unit 252 is composed of a low-pass filter. The signal that has passed through the integration processing unit 252 has a smooth waveform from which high frequency components have been removed.

The noise level estimation unit 253 estimates the noise level of the sound picked up by the speaker 3 based on the magnitude of the amplitude of the electromotive force signal input via the integration processing unit 252. The noise level estimation unit 253 determines, for example, the noise level of the sound picked up by the speaker 3 in three stages of large, medium, and small. Specifically, when the noise level is equal to or higher than the first threshold value, it is determined that the noise level is large, and when the noise level is smaller than the first threshold value and equal to or higher than the second threshold value, it is determined that the noise level is medium. When the noise level is less than the second threshold value, it is determined that the noise level is low. Then, the output volume determination unit 27 is notified of the signal indicating the determined noise level.

The output volume determination unit 27 determines the volume of the notification sound to be sounded from the speaker 3 based on the noise level notified from the noise level estimation unit 253. The output volume determination unit 27 determines the volume level of the notification sound so that the louder the noise level notified from the noise level estimation unit 253, the louder the volume of the notification sound to be sounded from the speaker 3, and controls the sound of this volume. Notify department 21.

The sound generation control unit 21 outputs a notification sound voltage waveform signal corresponding to the volume level notified from the output volume determination unit 27 to the DA converter 281. The sound generation control unit 21 generates a notification sound voltage waveform signal so that the higher the noise level, the louder the volume of the notification sound to be sounded from the speaker 3.

The temperature estimation unit 26 estimates the sounding body temperature, which is the temperature of the speaker 3, based on the detection signals of the sensors 10 to 12 and the information from the engine ECU 13, and notifies the band control unit 254 of the sounding body temperature.

The various information input to the temperature estimation unit 26 is information that becomes an external factor of the change in the speaker temperature. That is, as the vehicle speed increases, the wind blows to the speaker 3 becomes stronger, and the speaker temperature may decrease. Further, the speaker temperature may fluctuate due to the influence of the temperature of the members existing around the speaker 3, such as the radiator temperature and the engine temperature. Similarly, the speaker temperature may fluctuate due to the influence of the outside air temperature. Further, if the engine operating time is long, the speaker temperature may rise due to the heat from the engine.

The temperature estimation unit 26 estimates the sounding body temperature in consideration of external factors of the speaker 3 based on the detection signals of the sensors 10 to 12 and the information from the engine ECU 13.

The band control unit 254 adjusts the filter characteristics of the filter 251 based on the sounding body temperature notified from the temperature estimation unit 26. Specifically, the band control unit 254 sets the parameters of the filter 251 so that a desired frequency characteristic can be obtained.

The filter 251 can set the center frequency of the blocking band, the attenuation amount of the blocking band, the Q value, and the like as parameters. By changing these parameters, it is possible to change the center frequency of the blocking band, the attenuation amount of the blocking band, the Q value, and the like.

The memory unit 255 stores frequency data obtained by individually measuring the peak frequency of the electromotive force signal output from the speaker 3 at a predetermined temperature. The memory unit 255 corresponds to a storage unit.

The band control unit 254 changes a specific blocking band of the filter 251 so as to correct the individual variation of the speaker 3 by using the frequency data stored in the memory unit 255.

Next, the temperature characteristics of the peak frequency of the electromotive force signal when the speaker 3 is made to function as a microphone will be described.

FIG. 2 shows the relationship between the peak frequency and the temperature of the electromotive force signal when the speaker 3 functions as a microphone. The horizontal axis of FIG. 2 is the temperature, and the vertical axis of FIG. 2 is the fluctuation amount of the peak frequency f0 of the electromotive force signal. The vertical axis of FIG. 2 is based on the peak frequency f0 of the electromotive force signal when the temperature of the speaker 3 is 25 ° C.

In the example of FIG. 2, the peak frequency f0 of the electromotive force signal becomes lower as the temperature of the speaker 3 rises. Further, the larger the temperature change, the larger the fluctuation amount of the peak frequency f0 of the electromotive force signal.

In this way, the peak frequency of the electromotive force signal when the speaker 3 functions as a microphone changes depending on the temperature of the speaker 3.

The amount of fluctuation of the peak frequency f0 of the electromotive force signal changes linearly. Therefore, it is possible to calculate the peak frequency f0 of the electromotive force signal by regarding it as a linear function of temperature.
Assuming that the sounding body temperature is T, the slope is A, and the intercept is B ₀ , it can be expressed as in the following mathematical formula 1.
(number)
f0 = AT + B ₀ ... Formula 1
The formula 1 is stored in the memory unit 22 of the microcomputer 20.
FIG. 3 shows the frequency characteristics of the electromotive force signal when the speaker 3 functions as a microphone. The amplitude of the voltage of the electromotive force signal at the peak frequency f0 is outstanding.

The sounding device 2 attenuates a specific blocking band corresponding to the peak frequency f0 of the electromotive force signal when the speaker 3 functions as a microphone with the filter 251.

FIG. 4 shows the frequency characteristics of the filter 251. The filter 251 is greatly attenuated in a specific blocking band corresponding to the peak frequency f0 of the electromotive force signal.

FIG. 5 shows the frequency characteristics of the electromotive force signal that has passed through the filter 251. By passing through the filter 251 the band of the peak frequency f0 of the electromotive force signal is attenuated to obtain a flat frequency characteristic.

However, the filter 251 has a property that the Q value is high and the blocking band is narrow. Therefore, if the peak frequency f0 of the electromotive force signal fluctuates due to the temperature change of the speaker 3, the peak frequency f0 of the electromotive force signal may not be sufficiently attenuated. In this case, the noise level estimation accuracy is lowered.

Therefore, the band control unit 254 specifies the sounding body temperature, which is the temperature of the speaker 3, and performs a process of changing the frequency characteristic of the filter 251 using the sounding body temperature.

Next, the processing of the band control unit 254 will be described with reference to FIG. The band control unit 254 periodically performs the process shown in FIG.

First, the band control unit 254 specifies the individual variation amount of the speaker 3 in S100. Specifically, the band control unit 254 specifies the individual variation amount of the speaker 3 by using the frequency data stored in the memory unit 255.

For example, when the peak frequency of the electromotive force signal at 25 ° C. is stored in the memory unit 255, the peak frequency f0 of the electromotive force signal at 25 ° C. is calculated using the mathematical formula 1 stored in the memory unit 22.

Next, the difference between the peak frequency at 25 ° C. stored in the memory unit 255 and the peak frequency f0 at 25 ° C. calculated using the linear function of Equation 1 is calculated as the individual variation amount of the speaker 3.

Further, the linear function of Equation 1 is corrected so that the peak frequency at 25 ° C. stored in the memory unit 255 is _{added to the intercept B 0 of Equation 1.}

For example, when the peak frequency at 25 ° C. stored in the memory unit 255 is 10 hertz higher than the peak frequency f0 of the electromotive force signal at 25 ° C. specified by using a linear function, the intercept B _{0 of} Equation 1 is 10 hertz. Correct the linear function of Equation 1 so as to add.

Further, when the peak frequency at 25 ° C. stored in the memory unit 255 is 10 hertz lower than the peak frequency f0 of the electromotive force signal at 25 ° C. specified by using a linear function, the intercept B ₀ to 10 hertz of Equation 1 Correct the linear function of Equation 1 so as to subtract.

Next, the band control unit 254 specifies the sounding body temperature in S102. The band control unit 254 specifies the sounding body temperature based on the sounding body temperature notified from the temperature estimating unit 26.

Next, the band control unit 254 specifies the peak frequency f0 of the electromotive force signal in S104. Specifically, using the sounding body temperature specified in S102, the peak frequency f0 of the electromotive force signal is calculated by regarding it as a linear function of temperature. Here, the peak frequency f0 of the electromotive force signal is specified by using the mathematical formula corrected in S100.

Next, the band control unit 254 controls the frequency band of the filter 251 in S106. Specifically, the band control unit 254 sets each parameter of the filter 251 so that the blocking band of the filter 251 corresponds to the peak frequency of the electromotive force signal corrected in S104, and ends this process. As a result, the blocking band of the filter 251 corresponds to the peak frequency of the electromotive force signal.

In FIG. 7, (a) shows the peak frequency f1 when the electromotive force signal is at room temperature (for example, 25 ° C.), the peak frequency f2 when the electromotive force signal is at high temperature (for example, 60 ° C.), and the electromotive force signal. The peak frequency f3 at low temperature (eg −10 ° C.) is shown.

As shown in FIG. 7B, the band control unit 254 changes the frequency band of the filter 251 based on the sounding body temperature.

In FIG. 7, (b) shows the blocking band C1 of the filter 251 at room temperature, the blocking band C2 of the filter 251 at high temperature, and the blocking band C3 of the filter 251 at low temperature.

The blocking band C1 of the filter 251 at room temperature includes the peak frequency f1 of the electromotive force signal at room temperature, and corresponds to the peak frequency f1. Further, the blocking band C2 of the filter 251 at the time of high temperature includes the peak frequency f2 at the time of high temperature of the electromotive force signal, and corresponds to the peak frequency f2. Further, the blocking band C3 of the filter 251 at a low temperature includes the peak frequency f3 at a low temperature of the electromotive force signal, and corresponds to the peak frequency f3.

Even if the temperature of the speaker 3 changes, the blocking band of the filter 251 changes so as to follow the peak frequency of the electromotive force signal, and the peak frequency of the electromotive force signal is attenuated. It has such a flat frequency characteristic.

Next, the volume adjustment process by the volume adjustment unit composed of the output volume determination unit 27 and the sound control unit 21 will be described with reference to FIG. The volume adjusting unit adjusts the volume of the notification sound emitted from the speaker 3 sounding body according to the noise level of the sound estimated by the noise level estimating unit. The volume adjusting unit periodically performs the process shown in FIG.

First, the volume adjusting unit determines in S200 whether or not the noise level estimated by the noise level estimating unit 253 is large. Further, when the volume adjusting unit determines that the noise level estimated by the noise level estimation unit 253 is not large, the volume adjusting unit determines in S204 whether or not the noise level estimated by the noise level estimation unit 253 is medium. To do. Further, when the volume adjusting unit determines that the noise level estimated by the noise level estimating unit 253 is not medium, the volume adjusting unit determines that the noise level is low.

Here, when the noise level estimated by the noise level estimation unit 253 is large, the volume adjustment unit adjusts the notification sound voltage waveform so that the volume of the notification sound emitted from the speaker 3 becomes large in S202. A signal is generated and this process ends.

Further, when the noise level estimated by the noise level estimation unit 253 is medium, the volume adjustment unit sets the notification sound voltage waveform signal in S206 so that the volume of the notification sound emitted from the speaker 3 is medium. Is generated, and this process is terminated.

When the noise level estimated by the noise level estimation unit 253 is low, the volume adjustment unit sets the notification sound voltage waveform signal in S210 so that the volume of the notification sound emitted from the speaker 3 becomes low. Is generated, and this process is terminated.

In this way, for example, the volume of the notification sound is increased along the main road where the noise level is high, and the volume of the notification sound is decreased at a quiet night when the noise level is low.

As described above, the present sounding device is a device for sounding a notification sound from a speaker 3 having a sounding function for sounding and a sound collecting function for outputting an electromotive force signal corresponding to the collected sound. The sounding apparatus includes a filter 251 that attenuates a specific blocking band corresponding to the peak frequency of the electromotive force signal output from the speaker 3. It also includes a noise level estimation unit 253 that estimates the noise level of the sound collected by the speaker 3 based on the electromotive force signal that has passed through the filter 251. Further, the volume adjusting units 21 and 27 for adjusting the volume of the notification sound emitted from the speaker 3 according to the noise level of the sound estimated by the noise level estimating unit 253, and the sounding body temperature which is the temperature of the speaker 3 are estimated. It includes a temperature estimation unit 26. In addition, a band control unit 254 that changes a specific blocking band of the filter 251 using the sounding body temperature estimated by the temperature estimation unit 26 is provided.

According to such a configuration, the sounding body temperature, which is the temperature of the sounding body, is estimated by the temperature estimating unit 26, and the specific blocking band of the filter is changed by using the sounding body temperature estimated by the temperature estimating unit 26. Therefore, it is possible to suppress a decrease in the estimation accuracy of the noise level due to the temperature change of the speaker.

Further, the band control unit 254 specifies the peak frequency of the electromotive force signal based on the sounding body temperature estimated by the temperature estimation unit 26, and sets a specific blocking band of the filter so as to correspond to the peak frequency of the electromotive force signal. Change.

In this way, the peak frequency of the electromotive force signal can be specified based on the temperature of the sounding body, and the specific blocking band of the filter can be changed so as to correspond to the peak frequency of the electromotive force signal.

Further, the sounding apparatus includes a memory unit 255 for storing frequency data obtained by individually measuring the peak frequency of the electromotive force signal output from the sounding body at a predetermined temperature. Then, the band control unit changes the specific blocking band of the filter so as to correct the individual variation of the speaker 3 by using the frequency data stored in the memory unit 255. Therefore, the band control unit estimates the noise level due to the individual variation of the sounding body. It is possible to suppress a decrease in accuracy.

(Other embodiments)
(1) In the above embodiment, the sounding device 2 has shown an example of outputting a locking notification sound and a half-door notification sound to the surroundings of the vehicle. For example, a notification for notifying the approach of a hybrid vehicle or an electric vehicle. It can also be configured as a vehicle approach notification device that emits a sound.

(2) In the above embodiment, an example in which the sounding device 2 is mounted on a vehicle is shown, but the present invention is not limited to that mounted on the vehicle.

(3) The temperature of the speaker 3 is estimated. For example, a temperature sensor for detecting the temperature of the speaker 3 may be provided, and the temperature sensor may be used to detect the temperature of the speaker 3.

(4) The noise level estimation unit 253 of the above embodiment sets the noise level of the sound picked up by the speaker 3 to large or medium based on the magnitude of the amplitude of the electromotive force signal input via the integration processing unit 252. , Small and small. On the other hand, the noise level may be determined in two stages, or the noise level may be determined in four or more stages.

(5) The band control unit 254 of the above embodiment corrects the peak frequency of the electromotive force signal specified based on the sounding body temperature estimated by the temperature estimation unit 26 by using the frequency data stored in the memory unit 255. I tried to do it. However, it is not always necessary to make such a correction.

(6) The band control unit 254 of the above embodiment identifies the peak frequency of the electromotive force signal based on the sounding body temperature estimated by the temperature estimation unit 26, and filters 251 so as to correspond to the peak frequency of the electromotive force signal. Changed to change the specific blocking band of.

On the other hand, the specific blocking band of the filter 251 may be changed without specifying the peak frequency of the electromotive force signal.

(7) In the above embodiment, the filter 251 is configured by the peaking filter, but the filter 251 is not limited to the peaking filter. For example, the filter 251 may be configured by a filter such as a band stop filter or a notch filter.

The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope of the claims. Further, the above-described embodiments are not unrelated to each other, and can be appropriately combined unless the combination is clearly impossible. Further, in each of the above embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential except when it is clearly stated that they are essential and when they are clearly considered to be essential in principle. No. Further, in each of the above embodiments, when numerical values such as the number, numerical values, amounts, and ranges of the constituent elements of the embodiment are mentioned, when it is clearly stated that they are particularly essential, and in principle, the number is clearly limited to a specific number. It is not limited to the specific number except when it is done. In addition, in each of the above embodiments, when referring to the material, shape, positional relationship, etc. of the components, etc., except when specifically specified or when the material, shape, positional relationship, etc. are limited to a specific material, shape, positional relationship, etc. in principle. , The material, shape, positional relationship, etc. are not limited.

2 Sounding device 3 Speaker 10 Vehicle speed sensor 11 Liquid temperature sensor 12 Outside air temperature sensor 13 Engine ECU
20 Microcomputer 21 Sound control unit 22 Memory unit 24 Switching unit 25 Noise estimation processing unit 26 Temperature estimation unit 27 Output volume determination unit 251 Filter 252 Integral processing unit 253 Noise level estimation unit 254 Band control unit 255 Memory unit

Claims (3)

It is a sounding device that sounds a notification sound from a sounding body (3) having a sounding function for pronouncing and a sound collecting function for outputting an electromotive force signal corresponding to the collected sound.
A filter (251) that attenuates a specific blocking band corresponding to the peak frequency of the electromotive force signal output from the sounding body, and
A noise level estimation unit (253) that estimates the noise level of the sound collected by the sounding body based on the electromotive force signal that has passed through the filter.
A volume adjusting unit (21, 27) that adjusts the volume of the notification sound emitted from the sounding body according to the noise level of the sound estimated by the noise level estimating unit.
A temperature estimation unit (26) that estimates the temperature of the sounding body, which is the temperature of the sounding body,
A sounding apparatus including a band control unit (254) that changes the specific blocking band of the filter using the sounding body temperature estimated by the temperature estimating unit. The band control unit identifies the peak frequency of the electromotive force signal based on the sounding body temperature estimated by the temperature estimation unit, and blocks the filter so as to correspond to the peak frequency of the electromotive force signal. The sounding apparatus according to claim 1, wherein the band is changed. A storage unit (255) for storing frequency data obtained by individually measuring the peak frequency of the electromotive force signal output from the sounding body at a predetermined temperature is provided.
The sounding device according to claim 2, wherein the band control unit uses the frequency data stored in the storage unit to change the specific blocking band of the filter so as to correct individual variations of the sounding body.

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