Inspection sound signal

Abstract

To provide an inspection sound signal capable of preventing a person in the periphery from having discomfort and improving accuracy in inspecting a speaker.SOLUTION: An inspection sound signal SA is the signal to inspect a sound state from a speaker of an emergency broadcasting facility. The inspection sound signal SA includes: a first sound component CA within a reproduction frequency band of the speaker; and a second sound component CB with a frequency band lower than the reproduction frequency band of the speaker. The first sound component CA is the sound component including at least a part of a frequency band constituting signal sound to be reproduced when emergency broadcasting is performed by the emergency broadcasting facility. The frequency of the second sound component CB is lower than the lowest frequency of the first sound component CA and also does not include the frequency band constituting the signal sound of the first sound component CA.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to test audio signals. [Background technology]

[0002] There is known technology for inspecting speakers (for example, Patent Document 1). In the technology described in Patent Document 1, a test signal having a frequency outside the reproduction frequency band of the speaker is input to the speaker. Then, the sound output by the speaker that received the test signal is picked up by a microphone, and the state of the speaker is judged based on the sound pressure level of the sound. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 58-129800 Summary of the Invention [Problem to be solved by the invention]

[0004] To accurately test the deterioration state of a speaker, it is preferable to input a signal with a frequency within the playback frequency band to the speaker at its rated power. However, inputting such a signal at its rated power results in a very loud volume output from the speaker, which may cause inconvenience to people around the speaker. As described in Patent Document 1, a speaker can be inspected without producing sound by inputting a signal with a frequency outside the playback frequency band. However, when inputting a signal with a frequency outside the playback frequency band, it is unclear whether the inspection will correctly output sound within the playback frequency band, and there is also a risk that the speaker may not be sufficiently loaded. As a result, such inspection may not detect speaker abnormalities that occur when a large load is applied to the speaker, such as emergency broadcasts. More specifically, there is a risk that abnormalities specific to the playback frequency band, such as peaks and dips in the frequency characteristics, or abnormalities in characteristics such as sound pressure sensitivity, may not be accurately detected. Therefore, the present disclosure aims to provide an inspection audio signal that is less likely to cause discomfort to people around the speaker and improves the accuracy of speaker inspections. [Means for solving the problem]

[0005] (1) The test audio signal that solves the problem is a test audio signal for testing the audio state from a speaker of an emergency broadcast equipment, and includes a first audio component within the playback frequency band of the speaker and a second audio component in a band lower than the playback frequency band of the speaker, wherein the first audio component is an audio component that includes at least a part of the frequency band that constitutes the signal sound that is played when the emergency broadcast equipment makes an emergency broadcast, and the frequency of the second audio component is an audio component that is lower than the minimum frequency of the first audio component and does not include the frequency band that constitutes the signal sound of the first audio component.

[0006] According to this configuration, the test sound signal includes a first sound component and a second sound component. Therefore, the second sound component easily vibrates the speaker. Furthermore, the frequency of the second sound component does not include the frequency band that constitutes the signal sound of the first sound component. This reduces discomfort to people around the speaker and improves the accuracy of the speaker test.

[0007] (2) In the test sound signal described in (1) above, the signal sound is a sound in the audible range.

[0008] (3) In the test audio signal described in (1) or (2) above, the frequency of the second audio component is 40 Hz. With this configuration, noise can be suppressed when testing a speaker.

[0009] (4) In the test sound signal according to any one of (1) to (3), the amplitude of the first sound component is smaller than the amplitude of the second sound component. With this configuration, it is possible to reduce the sound emitted from the speaker during the test.

[0010] (5) In the test audio signal described in any one of (1) to (4) above, the second audio component is configured so that the magnitude of vibration of the speaker when an output signal formed by reproducing the test audio signal is input to the speaker is substantially equal to the magnitude of vibration of the speaker when the signal sound signal is input to the speaker at its rated input.

[0011] Here, the rated power refers to the standard audio signal power input to a speaker so that a predetermined audio signal (predetermined signal) determined by test conditions, etc., is output from the speaker at a predetermined sound pressure (dB). For example, in the case of emergency broadcast equipment, this is the audio signal input power (effective AC voltage of 100V: 282V peak-to-peak) that ensures a sound pressure of 92dB 1m directly below the speaker when a sweep sound (signal sound) including a frequency band of 300Hz to 2KHz is output from the speaker. The rated input indicates the signal input to the speaker at its rated level.

[0012] According to this configuration, when an output signal obtained by reproducing the test audio signal is input to a speaker, the amplitude of the first audio component within the reproduction frequency band can be smaller than the amplitude when a signal audio signal is input at its rated input, so the volume output from the speaker is low, reducing discomfort to people around. Furthermore, inputting an output signal of the second audio component of the test audio signal can vibrate the speaker at a magnitude substantially equivalent to the speaker vibration when a signal audio signal is input at its rated input. In this way, speaker testing can be performed in a state that reproduces the speaker vibration state when a signal audio signal is input at its rated input, thereby improving the accuracy of speaker testing.

[0013] The following are related technologies to the disclosed technology. (1) A speaker testing system according to related technology includes a control unit that controls the testing of a speaker, a playback unit that forms an output signal by playing a test audio signal based on instructions from the control unit, an output unit that outputs the output signal to the speaker, a sound collection unit that collects output sound output from the speaker that has received the output signal, and a judgment unit that judges the state of the speaker, wherein the test audio signal includes a first sound component within the reproduction frequency band of the speaker and a second sound component in a band lower than the reproduction frequency band of the speaker, and the second sound component is configured so that the magnitude of vibration of the speaker when the output signal is input to the speaker is substantially equal to the magnitude of vibration of the speaker when a predetermined signal within the reproduction frequency band is input to the speaker at its rated level, and the amplitude of the first sound component is smaller than the amplitude of the second sound component, and the judgment unit judges the state of the speaker based on the first sound component in the output sound collected by the sound collection unit. Here, the rated power refers to the standard audio signal power input to a speaker so that a predetermined audio signal (predetermined signal) determined by test conditions, etc., is output from the speaker at a predetermined sound pressure (dB). For example, in the case of emergency broadcast equipment, this is the audio signal input power (effective AC voltage of 100V: 282V peak-to-peak) that ensures a sound pressure of 92dB 1m directly below the speaker when a sweep sound (signal sound) including a frequency band of 300Hz to 2KHz is output from the speaker. The rated input indicates the signal input to the speaker at its rated level.

[0014] According to this configuration, the amplitude of the first sound component in the reproduction frequency band in the test audio signal can be smaller than the amplitude when a predetermined signal in the reproduction frequency band is input at its rated level, so the volume output from the speaker is low, reducing discomfort to people around. Furthermore, inputting the output signal of the second sound component of the test audio signal can vibrate the speaker at a level substantially equivalent to the vibration of the speaker when a predetermined signal in the reproduction frequency band is input at its rated level. This allows speaker testing to be performed in a state that reproduces the vibration state of the speaker when a predetermined signal in the reproduction frequency band is input at its rated level, thereby improving the accuracy of the speaker testing.

[0015] (2) The speaker testing system described in (1) above further includes a first mixing unit that forms the test audio signal by mixing, and the first mixing unit forms the test audio signal by mixing a first signal obtained by amplifying a first audio component signal within the playback frequency band of the speaker with a first amplification factor, and a second signal obtained by amplifying a second audio component signal in a band lower than the playback frequency band of the speaker with a second amplification factor.

[0016] With this configuration, the second amplification factor can be freely changed, making it easy to adjust the load on the speaker. Also, the first amplification factor can be freely changed, making it possible to change the magnitude of the first sound component signal according to the level of background noise picked up by the sound pickup unit.

[0017] (3) The speaker testing system described in (1) above further includes a first signal generator, a second signal generator, and a second mixing unit that forms the test audio signal by mixing, wherein the first signal generator forms a first audio component signal within the reproduction frequency band of the speaker and amplifies the first audio component signal by a first amplification factor to form a first signal including the first audio component, the second signal generator forms a second audio component signal in a band lower than the reproduction frequency band of the speaker and amplifies the first audio component signal by a second amplification factor to form a second signal including the second audio component, and the second mixing unit forms the test audio signal by mixing the first signal and the second signal. With this configuration, the first audio component and the second audio component can be freely changed.

[0018] (4) In the speaker testing system described in any one of (1) to (3) above, the determining unit determines that the speaker is normal when the volume of the output sound is greater than a first threshold. With this configuration, the state of the speaker can be determined based on the volume of the output sound of the speaker.

[0019] (5) In the speaker testing system described in any one of (1) to (4) above, the determining unit determines that the speaker is normal when the frequency spectrum of the output sound substantially matches the frequency spectrum of a reference sound. With this configuration, the state of the speaker can be determined based on the frequency spectrum (hereinafter also referred to as timbre) of the output sound of the speaker.

[0020] (6) In the speaker testing system described in (5) above, the frequency spectrum is sequence data or image data for each frequency. This configuration allows the state of the speaker to be determined more accurately than when the state of the speaker is determined based on only one predetermined frequency.

[0021] (7) In the speaker testing system according to any one of (4) to (6), when the determination unit determines that the speaker is not normal, the determination unit identifies a difference between the frequency spectrum of the output sound and the frequency spectrum of a reference sound, and estimates the nature of the abnormality of the speaker based on the difference and abnormality reference data indicating the relationship between the abnormality and frequency. With this configuration, the nature of the abnormality of the speaker can be estimated.

[0022] (8) In the speaker testing system described in any one of (1) to (7) above, the control unit acquires background noise from the sound collection unit as pre-processing before starting the speaker testing, starts the speaker testing if the level of the background noise is smaller than a second threshold, stops the speaker testing if the level of the background noise is equal to or greater than the second threshold, and performs the pre-processing before starting the speaker testing again after a predetermined time has elapsed. With this configuration, the speaker testing is performed when the level of background noise is small, thereby improving the accuracy of the speaker testing.

[0023] (9) In the speaker testing system described in (2) above, the control unit acquires background noise from the sound pickup unit as preprocessing before starting the speaker testing. If the magnitude of the background noise is smaller than a second threshold, the control unit starts the speaker testing. If the magnitude of the background noise is equal to or greater than the second threshold, the control unit changes the first amplification factor according to the magnitude of the background noise and then starts the speaker testing. With this configuration, the first amplification factor is changed according to the magnitude of the background noise, which improves the accuracy of the speaker testing. Furthermore, the speaker testing can be performed even when there is some background noise.

[0024] (10) In the speaker inspection system according to any one of (1) to (9), the sound pickup unit includes a high-sensitivity sound pickup unit and a low-sensitivity sound pickup unit having a lower sensitivity than the high-sensitivity sound pickup unit, and the control unit operates the low-sensitivity sound pickup unit during inspection of the speaker. This configuration makes it difficult to pick up background noise, thereby improving the accuracy of the speaker inspection.

[0025] (11) A speaker inspection method according to related art is a speaker inspection method for inspecting a speaker, comprising: a first step of forming an output signal by playing back a test audio signal; a second step of outputting the output signal to the speaker; a third step of collecting output sound output from the speaker that has received the output signal; and a fourth step of determining the state of the speaker, wherein the test audio signal comprises a first sound component within the reproduction frequency band of the speaker and a second sound component in a band lower than the reproduction frequency band of the speaker, and the second sound component is configured so that the magnitude of vibration of the speaker when the output signal is input to the speaker is substantially equal to the magnitude of vibration of the speaker when a predetermined signal within the reproduction frequency band is input to the speaker at its rated input, and the amplitude of the first sound component is smaller than the amplitude of the second sound component, and in the fourth step, the state of the speaker is determined based on the first sound component in the collected output sound.

[0026] According to this configuration, the amplitude of the first sound component within the playback frequency band in the test audio signal is smaller than the amplitude of the second sound component, thereby reducing discomfort to people around. Furthermore, inputting the output signal of the test audio signal to the speaker can vibrate the speaker at a magnitude substantially equivalent to the vibration of the speaker when a predetermined signal within the playback frequency band is input to the speaker at its rated input. In this way, the speaker can be tested in a state that reproduces the vibration state of the speaker when a predetermined signal within the playback frequency band is input to the speaker at its rated input, thereby improving the accuracy of the speaker test.

[0027] (12) A storage medium for a test audio signal according to related art is a storage medium storing information related to a test audio signal for testing a speaker, wherein the test audio signal includes a first audio component within the playback frequency band of the speaker and a second audio component in a band lower than the playback frequency band of the speaker, and the second audio component is configured so that when an output signal that reproduces the test audio signal is input to the speaker, the magnitude of the vibration of the speaker is substantially equal to the magnitude of the vibration of the speaker when a predetermined signal within the playback frequency band is input to the speaker at its rated input, and the amplitude of the first audio component is smaller than the amplitude of the second audio component.

[0028] According to this configuration, the amplitude of the first sound component within the playback frequency band in the test audio signal is smaller than the amplitude of the second sound component, thereby reducing discomfort to people around. Furthermore, inputting the output signal of the test audio signal to the speaker can vibrate the speaker at a magnitude substantially equivalent to the vibration of the speaker when a predetermined signal within the playback frequency band is input to the speaker at its rated input. In this way, the vibration state of the speaker when a predetermined signal within the playback frequency band is input to the speaker at its rated input can be reproduced. Therefore, by using information related to the test audio signal, the accuracy of speaker testing can be improved. [Effects of the Invention]

[0029] The test audio signal is less likely to cause discomfort to people around you and can improve the accuracy of speaker testing. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a block diagram of a speaker testing system. [Figure 2] 1 is a chart showing the frequency characteristics of a speaker. [Figure 3] 1 is a chart showing the relationship between the amplitude of a diaphragm and the frequency of an input signal for a speaker. [Figure 4]FIG. 2 is a schematic diagram showing the relationship between a test audio signal, a first audio component, and a second audio component. [Figure 5] 1 is a chart of a frequency spectrum of sound output from a normal speaker. [Figure 6] 10 is a frequency spectrum chart of the sound output from a speaker having an abnormality. [Figure 7] 1 is a table showing the relationship between an abnormal frequency location in a frequency spectrum and the cause of the abnormality. [Figure 8] FIG. 10 is a diagram for explaining the flow of speaker inspection. [Figure 9] FIG. 10 is a block diagram of another embodiment of a speaker testing system. [Figure 10] FIG. 10 is a block diagram of another embodiment of a speaker testing system. [Figure 11] FIG. 10 is a block diagram of another embodiment of a speaker testing system. [Figure 12] FIG. 10 is a block diagram of a speaker inspection system according to a second embodiment. [Figure 13] FIG. 10 is a block diagram of a speaker inspection system according to a third embodiment. [Figure 14] FIG. 10 is a schematic diagram of a modified example of the sound pickup unit. DETAILED DESCRIPTION OF THE INVENTION

[0031] First Embodiment A speaker inspection system 1 will be described with reference to FIGS. The speaker inspection system 1 inspects the speaker 3 connected to the broadcasting device 2. The broadcasting device 2 transmits various pieces of information by voice to people in the area where the sound from the speaker 3 reaches. Examples of information that the broadcasting device 2 transmits to people include announcements about greetings, announcements about business notices, announcements about disaster information, announcements about emergency situations other than disasters, etc. One of the purposes of installing the broadcasting device 2 is to reliably transmit information to people in emergencies. For this reason, it is preferable that the speaker 3 always operates normally. Therefore, the speaker 3 is inspected periodically or at specified times.

[0032] The speaker inspection system 1 is a system that can inspect a speaker 3 connected to a broadcasting device 2. In this embodiment, the speaker inspection system 1 inspects the speaker 3 connected to the broadcasting device 2 via the broadcasting device 2.

[0033] The broadcasting device 2 transmits the announcement audio signal to the speaker 3. The broadcasting device 2 is installed in a specific building. The speaker 3 includes one or more speakers 3. The multiple speakers 3 are connected to the broadcasting device 2 by wire or wirelessly. The speaker 3 may be installed indoors or outdoors. For example, outdoors, the speaker 3 may be installed on a utility pole, a steel tower, the roof of a public facility, the roof of a government office building, the roof of a private factory, or the roof of a private store.

[0034] The broadcasting device 2 may include a broadcasting microphone. The broadcasting device 2 transmits a microphone audio signal from the audio via the broadcasting microphone to the speaker 3.

[0035] The broadcasting device 2 transmits the microphone audio signal or the announcement audio signal to the speaker 3 via wire or wirelessly.

[0036] The broadcasting device 2 also transmits a test audio signal SA, which will be described later, to the speaker 3 via a wired or wireless connection. The test audio signal SA is information input from the speaker testing system 1 to the broadcasting device 2.

[0037] [Speaker frequency characteristics] As shown in Fig. 2, the speaker 3 has a predetermined frequency characteristic. The speaker 3 has a reproduction frequency band configured to overlap the human audible range. The reproduction frequency band may overlap the entire audible range. Alternatively, the reproduction frequency band may not overlap one or both of the end bands of the audible range.

[0038] Speaker 3 accepts the input of an audio signal at a rated power. The rated power indicates the standard audio signal power input to speaker 3 so that an audio signal (predetermined signal) predetermined by test conditions or the like is output from speaker 3 at a predetermined sound pressure (dB). For example, in the case of emergency broadcast equipment, the input power of the audio signal (effective value of AC voltage 100V: 282V peak-to-peak) is required to ensure a sound pressure of 92dB 1 meter directly below speaker 3 when a sweep sound (signal sound) including a frequency band of 300Hz to 2KHz is output from speaker 3.

[0039] As shown in Figure 3, when a signal of constant power is input to speaker 3, the magnitude of the diaphragm's amplitude varies depending on the frequency. According to Figure 3, even if the power of each signal input to speaker 3 is the same, the lower the frequency of the signal, the greater the amplitude of the diaphragm. In the example of speaker 3 shown in Figure 3, the magnitude of the diaphragm's amplitude when a 40 Hz signal is input to speaker 3 is approximately 10 times the magnitude of the diaphragm's amplitude when a signal of the lowest frequency (300 Hz) in the playback frequency band is input to speaker 3. Speaker 3 is designed to operate within the playback frequency band. Therefore, in order to input a signal outside the playback frequency band to speaker 3, it is necessary to consider the amplitude of the diaphragm when the signal is input to speaker 3.

[0040] [Speaker inspection system] As shown in FIG. 1, the speaker testing system 1 includes a control unit 11, a playback unit 12, an output unit 13, a sound collection unit 14, and a determination unit 15. In this embodiment, the speaker testing system 1 includes a memory unit 16. The speaker testing system 1 may not include an internal memory unit 16, but may instead be connected to an external memory unit 16. The speaker testing system 1 may also include an operation terminal 18 (see FIG. 9). The operation terminal 18 is connected to the control unit 11 via a wired or wireless connection. The operation terminal 18 may be connected to the control unit 11 via a network N, or may be connected directly to the control unit 11.

[0041] The operation terminal 18 is a mobile terminal or a personal computer. The mobile terminal includes a smart terminal. The smart terminal includes a smartphone, a tablet, and a notebook personal computer.

[0042] Examples of the network N include the Internet, a local network, a telephone line network, a dedicated line network such as RS-485, and a composite network in which these are connected.

[0043] [Control Unit] The control unit 11 controls the inspection of the speaker 3. The control unit 11 executes the inspection of the speaker 3 based on a schedule for the inspection of the speaker 3. The schedule is created in advance. The control unit 11 may execute the inspection of the speaker 3 based on a command from the operation terminal 18.

[0044] When inspecting the speaker 3, the control unit 11 causes the playback unit 12 to play back the test audio signal SA. When starting the inspection of the speaker 3, the control unit 11 instructs the storage unit 16, the playback unit 12, and the output unit 13 to play back the test audio signal SA. Immediately after starting the inspection of the speaker 3, the control unit 11 also instructs the sound collection unit 14 to collect the output sound SP emitted from the speaker 3. The control unit 11 further causes the determination unit 15 to determine the state (e.g., state of deterioration) of the speaker 3 based on the collected output sound SP.

[0045] The control unit 11 is configured by one or more central processing units (CPUs) or one or more micro processing units (MPUs).

[0046] [Playback Department] The reproducing unit 12 generates an output signal SB by reproducing the test audio signal SA based on instructions from the control unit 11. The output signal SB is a signal obtained by amplifying the test audio signal SA. Hereinafter, the output signal SB will also be referred to as the output signal SB related to the test audio signal SA, or as the output signal SB of the test audio signal SA. The reproducing unit 12 has an amplifier. The reproducing unit 12 amplifies the test audio signal SA at a predetermined amplification factor using the amplifier.

[0047] [Output section] The output unit 13 outputs the output signal SB to the speaker 3. A signal line leading to the speaker 3 is connected to the output unit 13.

[0048] [Storage] The storage unit 16 stores the test audio signal SA. In one example, the storage unit 16 stores the test audio signal SA as a test audio file F. The storage unit 16 stores a schedule file. The schedule file includes information on the test schedule of the speaker 3. The schedule file is stored by the operation terminal 18 in an updatable manner.

[0049] The storage unit 16 is configured by an optical disk, a magnetic disk, a magnetic tape, an SD card, a hard disk, a solid state drive (also called an SSD), a USB memory, a ROM (Read Only Memory), a RAM (Random Access Memory), or the like.

[0050] [Test audio signal] The test audio signal SA will be described with reference to Fig. 4. Fig. 4 is a diagram showing the test audio signal SA separated into low-frequency components and high-frequency components. The test audio signal SA is the original signal of the output signal SB input to the speaker 3 to test the speaker 3.

[0051] As shown in Figure 4, the test audio signal SA includes a first audio component CA and a second audio component CB. The first audio component CA is a high-frequency component of the test audio signal SA. The second audio component CB is a low-frequency component of the test audio signal SA. The first audio component CA has a frequency within the reproduction frequency band of the speaker 3. The amplitude of the first audio component CA is smaller than the amplitude of the second audio component CB.

[0052] The first sound component CA may be composed of signals of multiple frequencies within the playback frequency band, or may be composed of a signal of a single frequency. For example, the first sound component CA may be composed of pink noise or white noise. The first sound component CA may have a signal structure with a fixed frequency, or a signal structure with a variable frequency like a sweep sound.

[0053] The second sound component CB has a frequency outside the reproduction frequency band of the speaker 3. Specifically, the second sound component CB has a frequency in a band lower than the reproduction frequency band of the speaker 3. The second sound component CB may be composed of a signal of a single frequency, or may be composed of signals of multiple frequencies outside the reproduction frequency band.

[0054] In the example shown in Figure 4, the second sound component CB has a 40 Hz sinusoidal waveform structure. 50 Hz and 60 Hz are power supply frequencies in Japan, which can cause noise. For this reason, it is preferable that the second sound component CB does not include signals at 50 Hz and 60 Hz.

[0055] The second sound component CB is configured to satisfy the following condition: "The magnitude of vibration of the speaker 3 when the output signal SB is input to the speaker 3 is substantially the same as the magnitude of vibration of the speaker 3 when a predetermined signal within the reproduction frequency band is input to the speaker 3 at its rated level." In practice, if the predetermined signal has a frequency band width (for example, 300 Hz to 2 kHz), a signal of any frequency within this frequency band (for example, the lowest limit frequency) can be used as the reference.

[0056] The components that contribute most to the vibration of the speaker 3 are low-frequency components. Therefore, an example of setting the power of the second audio component CB will be described. Assume that the second audio component CB is composed of a 40 Hz signal. To simplify the explanation, consider a case where the signal of the second audio component CB is input to the speaker 3 at its rated level. In this case, when the signal of the second audio component CB is input to the speaker 3 at its rated level, the diaphragm vibrates with approximately 10 times the amplitude compared to when a signal of 300 Hz, the lowest frequency of the playback frequency band, is input to the speaker 3 at its rated level (see Figure 3). This may cause the speaker 3 to significantly exceed the amplitude allowed for reproduction of the playback frequency band. Therefore, the power of the second audio component CB is set to 1 / 10 of the rated power. For example, for the above-mentioned rated input of 282 V peak-to-peak, the power is set to approximately 28.2 V peak-to-peak. This allows the amplitude of the diaphragm of speaker 3 when the signal of the second audio component CB is input to speaker 3 to be substantially the same as when a specified signal in the playback frequency band is input at its rated value.

[0057] The test audio signal SA is amplified by the reproducing unit 12 before being input to the speaker 3. Therefore, the magnitude of the second audio component CB in the test audio signal SA is set to a value attenuated by the amount amplified by the reproducing unit 12.

[0058] [Sound pickup section] The sound pickup unit 14 picks up the output sound SP output from the speaker 3 that has received the output signal SB. The sound pickup unit 14 includes a microphone. The sound pickup unit 14 is disposed near the speaker 3. The sound pickup unit 14 may be provided in a case of the speaker 3. The sound pickup unit 14 may be installed near the speaker 3 when inspecting the speaker 3.

[0059] [Judgment section] The determination unit 15 acquires the output sound SP collected by the sound collection unit 14. The determination unit 15 determines the state (e.g., deterioration state) of the speaker 3 based on the output sound SP. Specifically, the determination unit 15 determines the state (e.g., deterioration state) of the speaker 3 based on a first sound component CA in the output sound SP collected by the sound collection unit 14.

[0060] [Sound pressure judgment] When the volume of the output sound SP is greater than the first threshold, the judgment unit 15 judges the speaker 3 to be normal in terms of sound pressure. When the volume of the output sound SP is equal to or less than the first threshold, the judgment unit 15 judges the speaker 3 to be abnormal in terms of sound pressure. The first threshold is set as follows: The first threshold is set in advance based on the volume of the sound output from a normal speaker 3 when the output signal SB of the test audio signal SA is input to the normal speaker 3. More specifically, the judgment unit 15 may make the judgment by collecting the output sound SP, performing a filter process that weights the band of the audio signal to be tested, and then comparing the calculated sound pressure level with the first threshold.

[0061] [Tone judgment] If the frequency spectrum of the output sound SP substantially matches the frequency spectrum of the reference sound, the determination unit 15 determines that the speaker 3 is normal. For example, if the frequency spectrum of the output sound SP is entirely within the range of the upper and lower limits of the frequency spectrum of the reference sound, the determination unit 15 can determine that they substantially match. The frequency spectrum includes data on the volume of sound at each frequency for each time.

[0062] FIG. 5 shows the frequency spectrum of the reference sound. The "reference sound" is the output sound SP output from a normal speaker 3 when an output signal SB related to the test sound signal SA is input to the normal speaker 3. The "frequency spectrum of the reference sound" shows the frequency spectrum of the signal formed by the sound pickup microphone when the output sound SP output from the normal speaker 3 is received by the sound pickup microphone. The sound pickup microphone is a microphone with performance equivalent to that of the microphone incorporated in the sound pickup unit 14.

[0063] Figure 6 shows the frequency spectrum of an abnormal sound. The "abnormal sound" is the output sound SP output from the abnormal speaker 3 when the output signal SB related to the test audio signal SA is input to the abnormal speaker 3. The "frequency spectrum of the abnormal sound" shows the frequency spectrum of the signal formed by the sound pickup microphone when the output sound SP output from the abnormal speaker 3 is received by the sound pickup microphone.

[0064] The frequency spectrum has a horizontal axis indicating time and a vertical axis indicating frequency. The density of the dots indicates the loudness of the sound. The storage unit 16 stores the frequency spectrum of the reference sound as sequence data or image data. The reference sound data stored in the storage unit 16 may be video data, audio data, or distribution data that serves as a basis for making a judgment based on the distribution characteristics of the fluctuations in the frequency spectrum of the output sound SP of the speaker 3 over a certain period of time.

[0065] 5 and 6, when the speaker 3 is abnormal, the tone of the output sound SP output by the speaker 3 changes. In the example of FIG. 6 showing the abnormal speaker 3, the dots are darker in the low frequency range. In other words, in the example of FIG. 6 showing the abnormal speaker 3, the sound is louder in some low frequencies compared to a normal speaker 3.

[0066] When the frequency spectrum is configured as sequence data for each frequency, the determination unit 15 compares the frequency spectrum of the output sound SP to be tested with the frequency spectrum of the reference sound. Then, the determination unit 15 compares the sound pressure for each frequency. If, at each frequency, the sound pressure of the frequency spectrum of the output sound SP to be tested is within a predetermined magnification range (for example, 0.9 to 1.0 times) of the sound pressure of the frequency spectrum of the reference sound, the determination unit 15 determines that the speaker 3 to be tested is normal in terms of tone.

[0067] If, for any one of the frequencies, the sound pressure of the frequency spectrum of the output sound SP to be tested is not within a predetermined magnification range of the sound pressure of the frequency spectrum of the reference sound, the judgment unit 15 judges that the speaker 3 to be tested is abnormal in terms of tone.

[0068] When the frequency spectrum is configured as image data, the determination unit 15 compares an image of the frequency spectrum of the output sound SP to be tested with an image of the frequency spectrum of the reference sound. The determination unit 15 then detects the difference between the two images. The difference is calculated as the difference in density of dots in a rectangular area surrounded by a predetermined time range and a predetermined frequency range. If the difference is smaller than a predetermined value, the determination unit 15 determines that the speaker 3 to be tested is normal. If the difference is equal to or greater than the predetermined value, the determination unit 15 determines that the speaker 3 to be tested is abnormal.

[0069] When the determination unit 15 determines that both the sound pressure determination and the tone determination are normal, it determines that the speaker 3 is normal.

[0070] Referring to FIG. 7, the estimation of the abnormality of the speaker 3 will be described. As shown in Fig. 7, the tone of the output sound SP of the speaker 3 changes depending on the cause of the abnormality in the speaker 3. Fig. 7 shows a table showing the relationship between the abnormal frequency points in the frequency spectrum and the cause of the abnormality. Using this table, the nature of the abnormality in the speaker 3 can be estimated based on the abnormal point in the frequency spectrum.

[0071] In this embodiment, when the determination unit 15 determines that the speaker 3 is abnormal, it identifies a difference between the frequency spectrum of the output sound SP and the frequency spectrum of the reference sound. Then, the determination unit 15 estimates the nature of the abnormality of the speaker 3 based on the difference and the abnormality reference data. For example, if there is a difference only in the band of 8 kHz or more, the determination unit 15 determines that there is a high possibility of cone edge damage. The abnormality reference data indicates the relationship between the nature of the abnormality and frequency. An example of the abnormality reference data is the table shown in FIG. 7.

[0072] The determination unit 15 is configured with one or more CPUs or one or more MPUs. The determination unit 15 may be configured integrally with the control unit 11. For example, a calculation device configured with one or more CPUs or one or more MPUs is configured to include the control unit 11 and the determination unit 15.

[0073] The flow of testing the speaker 3 will be described with reference to Fig. 8. In Fig. 8, the broadcasting device 2 includes a playback unit 12 and an output unit 13 in addition to a broadcasting unit related to normal broadcasting functions.

[0074] The speaker inspection system 1 executes the following first step S1 to tenth step S10. In the first step S1, the control unit 11 starts executing an inspection program for the speaker 3 based on a schedule or based on a command from the operation terminal 18. The inspection program includes a command to be executed by the control unit 11. The inspection program is stored in the storage unit 16.

[0075] In a second step S2, the control unit 11 turns on the sound collection unit 14. The sound collection unit 14 is turned on by being connected to the power supply of the sound collection unit 14. In the on state, the sound collection unit 14 collects sound.

[0076] In a third step S3, the control unit 11 outputs the test audio signal SA to the broadcasting device 2. Specifically, the control unit 11 retrieves the test audio signal SA from the storage unit 16. The control unit 11 sends the retrieved test audio signal SA to the playback unit 12 of the broadcasting device 2.

[0077] In a fourth step S4, the reproducing unit 12 receives the test audio signal SA from the control unit 11. In a fifth step S5, the reproducing unit 12 reproduces the received test audio signal SA. The reproducing unit 12 outputs the reproduced test audio signal SA to the speaker 3 as an output signal SB.

[0078] In a sixth step S6, the speaker 3 receives the output signal SB and outputs the output signal SB as the output sound SP. In a seventh step S7, the control unit 11 causes the output sound SP output from the speaker 3 to be collected.

[0079] In an eighth step S8, control unit 11 causes determination unit 15 to perform a sound pressure determination on output sound SP. In a ninth step S9, control unit 11 causes determination unit 15 to perform a tone color determination on output sound SP. In a tenth step S10, control unit 11 turns off sound pickup unit 14 after outputting the determination result.

[0080] [Additional Processing] To reduce the influence of background noise on the test results, the control unit 11 may acquire background noise from the sound collection unit 14 as pre-processing before starting the test of the speaker 3. In this embodiment, the "output of the test audio signal SA" is defined as the start of the test of the speaker 3. Therefore, the control unit 11 acquires background noise from the sound collection unit 14 at a timing after the second step S2 and before the third step S3.

[0081] The background noise is the sound picked up by the sound pickup unit 14 when no sound is being output from the speaker 3. The background noise is the sound around the speaker 3.

[0082] If the background noise is equal to or greater than the second threshold, the control unit 11 stops the inspection of the speaker 3. Then, after a predetermined time has elapsed since the inspection of the speaker 3 was stopped, the control unit 11 performs pre-processing again before starting the inspection of the speaker 3. The second threshold is a value set based on the loudness of sound that will not interfere with the inspection of the speaker 3. For example, the second threshold can be set to a value that is not more than a predetermined difference from the first threshold used by the judgment unit 15 to make a sound pressure judgment. The reason for setting the second threshold in this manner is that if there is background noise at a level not significantly different from the first threshold, it becomes difficult to accurately make the judgment in the eighth step S8, in which the background noise is compared with the first threshold. If the background noise is smaller than the second threshold, the control unit 11 starts the inspection of the speaker 3. That is, the control unit 11 performs the processing from the third step S3 onwards.

[0083] If the background noise is smaller than the second threshold, the control unit 11 sequentially executes the third step S3 and subsequent steps according to the flow shown in FIG. 8 . When the background noise is smaller than the second threshold and further satisfies the following condition, the determination condition of the eighth step S8 may be changed. This change is described below. When the background noise is smaller than the second threshold but larger than the third threshold, the determination unit 15 may correct the first threshold by increasing it, and then perform the determination of the eighth step S8. Here, the third threshold is a value that is smaller than the second threshold and sufficiently smaller than the first threshold so that a determination can be made. The third threshold is a value at a level where the background noise component is included in the output sound SP when the background noise and the output sound SP are picked up simultaneously, causing the detected value of the sound pressure of the output sound SP to exceed the value obtained by adding an error level to the original volume of the output sound SP. The third threshold is set, for example, to a value between 1 / 10 and 1 / 5 of the first threshold. If the judgment in step S8 is performed using the first threshold value when the noise level is greater than the third threshold value, the output sound SP will contain background noise components greater than the third threshold value, which may result in an overestimation of the sound pressure of the test sound signal SA and an erroneous judgment. Therefore, the judgment unit 15 corrects the first threshold value by a predetermined level. This ensures accurate judgment even under certain levels of background noise.

[0084] Furthermore, in order to reduce the influence of background noise on the test results, the control unit 11 may also acquire background noise from the sound collection unit 14 as post-processing after the test of the speaker 3 is completed. That is, after the control unit 11 completes the test of the speaker 3 and stops outputting the test audio signal SA, the control unit 11 acquires background noise from the sound collection unit 14 after the ninth step S9 and before the tenth step S10. If the background noise is equal to or greater than the second threshold, the control unit 11 invalidates the determination results made in the eighth step S8 or the ninth step S9. This is because if background noise is present after the test of the speaker 3 is completed, it is possible that background noise was also present when the determinations were made in the eighth step S8 or the ninth step S9, making the reliability of the determination results low. When the control unit 11 invalidates the determination results, it is preferable that the control unit 11 return to the third step S3 and start the test of the speaker 3 again after a predetermined time has elapsed.

[0085] [Speaker inspection system configuration] A specific system configuration of the speaker inspection system 1 will be described with reference to FIG. 1 and FIGS.

[0086] 1, speaker testing system 1 includes control unit 11, memory unit 16, playback unit 12, output unit 13, sound collection unit 14, and determination unit 15. In this example, control unit 11, memory unit 16, playback unit 12, output unit 13, sound collection unit 14, and determination unit 15 are integrated into a single package. In speaker testing system 1 shown in FIG. 1, in addition to control unit 11, memory unit 16, playback unit 12, output unit 13, sound collection unit 14, and determination unit 15, a broadcasting device 2 may also be integrated.

[0087] In the example of FIG. 9, the speaker inspection system 1 includes a sound collection unit 21, a control unit 22, and a playback unit 23. Each unit is configured as an independent device. Each unit includes a communication device for communicating with the other units. The sound collection unit 21 includes a sound collection section 14. The control unit 22 includes a control section 11, a determination section 15, and a storage section 16. The control unit 22 is connected to an operation terminal 18 via a network N. The playback unit 23 includes a playback section 12 and an output section 13. The playback unit 23 is connected to an external input of the broadcasting device 2. The sound collection unit 21, the control unit 22, and the playback unit 23 communicate with each other wirelessly. These units transmit signals to each other wirelessly. Examples of wireless standards include wireless LAN and Bluetooth (registered trademark).

[0088] In the example of FIG. 10, the speaker inspection system 1 has a first system unit 27. The first system unit 27 includes a control unit 22 and a playback unit 23. In the first system unit 27, the control unit 22 and the playback unit 23 are integrated. The playback unit 23 in the first system unit 27 is connected to an external input of the broadcasting device 2. The first system unit 27 is connected to the operation terminal 18 via a network N. The first system unit 27 and the sound collection unit 21 communicate with each other wirelessly.

[0089] In the example of FIG. 11, the speaker inspection system 1 has a second system unit 28. The second system unit 28 includes a control unit 22, a playback unit 23, and a broadcasting device 2. In the second system unit 28, the control unit 22, the playback unit 23, and the broadcasting device 2 are integrated. The second system unit 28 is connected to the operation terminal 18 via a network N. The second system unit 28 and the sound collection unit 21 communicate with each other wirelessly.

[0090] 9 to 11, when multiple speakers 3 are connected to the broadcasting device 2, such as in an in-house broadcasting system or an emergency broadcasting system, it is preferable to provide an individual sound collection unit 21 for each speaker 3. In this case, multiple sound collection units 21 corresponding to the multiple speakers 3 are connected to a determination unit including a determination section 15. The determination unit may perform a determination for each speaker 3 sequentially, for example, by time sharing, or may perform a determination for all speakers 3 substantially simultaneously.

[0091] 9 to 11, the determination unit 15 may be provided in the sound collection unit 21. In this case, the determination is performed by the determination unit 15 in the sound collection unit 21, and the determination result is transmitted from the sound collection unit 21 to the control unit 22.

[0092] In the configuration examples shown in FIGS. 9 to 11, the connections between the units are not limited to wireless connections, but may be wired connections.

[0093] [Operation of this embodiment] In the speaker testing system 1, the playback unit 12 generates an output signal SB by playing back the test sound signal SA. The sound collection unit 14 collects an output sound SP. The determination unit 15 determines the state (e.g., deterioration state) of the speaker 3 based on a first sound component CA in the output sound SP collected by the sound collection unit 14.

[0094] The test sound signal SA includes a first sound component CA within the reproduction frequency band of the speaker 3 and a second sound component CB in a band lower than the reproduction frequency band of the speaker 3. The second sound component CB is a sound component in a band lower than the reproduction frequency band of the speaker 3, and therefore the sound of the second sound component CB is difficult for people to hear.

[0095] The second audio component CB is configured so that the amplitude of the diaphragm of the speaker 3 at rated input in normal use can be achieved when the signal of the second audio component CB is input to the speaker 3. Specifically, as described above, the second audio component CB is configured so that the magnitude of the vibration of the speaker 3 when the output signal SB is input to the speaker 3 is substantially the same as the magnitude of the vibration of the speaker 3 when a predetermined signal within the reproduction frequency band is input to the speaker 3 at rated input.

[0096] Therefore, by inputting the output signal SB corresponding to the test audio signal SA to the speaker 3, the amplitude of the diaphragm of the speaker 3 at the rated input during normal use is realized. This allows the speaker 3 to be tested under a load equivalent to that during normal use. Therefore, the condition of the speaker 3 (for example, the state of deterioration) can be determined more accurately than when simply inputting a small predetermined signal to the speaker 3 to test the speaker 3.

[0097] [Effects of this embodiment] (1) The test sound signal SA includes a first sound component CA within the reproduction frequency band of the speaker 3 and a second sound component CB in a band lower than the reproduction frequency band of the speaker 3. The second sound component CB is configured so that the magnitude of vibration of the speaker 3 when the output signal SB is input to the speaker 3 is substantially equal to the magnitude of vibration of the speaker 3 when a predetermined signal within the reproduction frequency band is input to the speaker 3 at its rated input. The amplitude of the first sound component CA is smaller than the amplitude of the second sound component CB.

[0098] According to this configuration, in the test audio signal SA, the amplitude of the first audio component CA within the reproduction frequency band can be smaller than the amplitude when a predetermined signal within the reproduction frequency band is input at its rated level. This reduces the volume of sound output from the speaker 3, reducing the discomfort felt by people in the vicinity. Furthermore, by inputting the output signal SB of the second audio component CB of the test audio signal SA, the speaker 3 can be vibrated at a level substantially equivalent to the vibration of the speaker 3 when a predetermined signal within the reproduction frequency band is input at its rated level. In this way, the speaker 3 can be tested in a state that reproduces the vibration state of the speaker 3 when a predetermined signal within the reproduction frequency band is input at its rated level, thereby improving the accuracy of the test of the speaker 3.

[0099] (2) When the volume of the output sound SP is greater than the first threshold, the determination unit 15 determines that the speaker 3 is normal. According to this configuration, the state of the speaker 3 can be determined based on the volume of the output sound SP of the speaker 3.

[0100] (3) When the frequency spectrum of the output sound SP substantially matches the frequency spectrum of the reference sound, the determination unit 15 determines that the speaker 3 is normal. According to this configuration, the state of the speaker 3 can be determined based on the frequency spectrum of the output sound SP of the speaker 3.

[0101] (4) The frequency spectrum is sequence data or image data for each frequency. This configuration allows the state of the speaker 3 to be determined more accurately than when the state of the speaker 3 is determined based on only one predetermined frequency.

[0102] (5) When the determination unit 15 determines that the speaker 3 is abnormal, it identifies a difference between the frequency spectrum of the output sound SP and the frequency spectrum of the reference sound, and estimates the nature of the abnormality of the speaker 3 based on the difference and the abnormality reference data. With this configuration, it is possible to estimate the nature of the abnormality of the speaker 3.

[0103] (6) Before starting the inspection of the speaker 3, the control unit 11 acquires background noise from the sound collection unit 14 as pre-processing. If the magnitude of the background noise is smaller than the second threshold, the control unit 11 starts the inspection of the speaker 3. If the magnitude of the background noise is equal to or greater than the second threshold, the control unit 11 stops the inspection of the speaker 3 and, after a predetermined time has elapsed, performs the pre-processing again before starting the inspection of the speaker 3. With this configuration, the inspection of the speaker 3 is performed when the magnitude of the background noise is small, thereby improving the accuracy of the inspection of the speaker 3.

[0104] Second Embodiment A speaker inspection system 1 according to the second embodiment will be described with reference to FIG. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description of the overlapping components will be omitted.

[0105] In the first embodiment, the test audio signal SA is stored as a test audio file F in the storage unit 16. In contrast, in the present embodiment, the test audio signal SA is formed by mixing signals. The formation of the test audio signal SA will be described below.

[0106] The speaker testing system 1 further includes a first mixing unit 31. The first mixing unit 31 mixes the first signal and the second signal to form a test audio signal SA.

[0107] The first signal is a signal obtained by amplifying, by a first amplification factor, a first sound component signal corresponding to a first sound component CA within the reproduction frequency band of the speaker 3. The first sound component signal is extracted from a first sound component file FA stored in the storage unit 16. The second signal is a signal obtained by amplifying, by a second amplification factor, a second audio component signal corresponding to a second audio component CB in a band lower than the reproduction frequency band of the speaker 3. The second audio component signal is extracted from a second audio component file FB stored in the storage unit 16.

[0108] The first amplification factor is an amplification factor for amplifying the first audio signal so that the power of the first signal is smaller than the power of the second signal. The second amplification factor is an amplification factor for amplifying the second audio signal so as to satisfy the following condition: the magnitude of vibration of the speaker 3 when the output signal SB including the second signal is input to the speaker 3 is substantially equal to the magnitude of vibration of the speaker 3 when a predetermined signal within the reproduction frequency band is input to the speaker 3 at its rated level.

[0109] According to such a speaker testing system 1, the second amplification factor can be freely changed, which makes it easy to adjust the load on the speaker 3. Furthermore, since the first amplification factor can be freely changed, the magnitude of the first sound component signal can be changed according to the magnitude of the background noise picked up by the sound pickup unit 14.

[0110] In this embodiment, the pre-processing shown in the first embodiment can be modified as follows: Modified examples of the pre-processing will be described below.

[0111] Before starting the inspection of the speaker 3, the control unit 11 acquires background noise from the sound collection unit 14 as pre-processing. If the magnitude of the background noise is smaller than the second threshold, the control unit 11 starts the inspection of the speaker 3. If the magnitude of the background noise is equal to or greater than the second threshold, the control unit 11 changes the first amplification factor according to the magnitude of the background noise and then starts the inspection of the speaker 3. Specifically, if the magnitude of the background noise is equal to or greater than the second threshold, the control unit 11 increases the first amplification factor so that the larger the background noise is, the larger the value of the first amplification factor becomes, and then starts the inspection of the speaker 3.

[0112] According to this configuration, the first amplification factor is changed depending on the level of background noise, thereby improving the accuracy of testing the speaker 3. Furthermore, even when there is some background noise, testing of the speaker 3 can be performed.

[0113] Third Embodiment A speaker inspection system 1 according to a third embodiment will be described with reference to FIG. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description of the overlapping components will be omitted.

[0114] In the first embodiment, the test audio signal SA is stored as a test audio file F in the storage unit 16. In contrast, in the present embodiment, the test audio signal SA is formed by mixing signals. The formation of the test audio signal SA will be described below.

[0115] The speaker testing system 1 further includes a first signal generator 41, a second signal generator 42, and a second mixing unit 43. The second mixing unit 43 forms a test audio signal SA by mixing signals.

[0116] The first signal generator 41 forms a first sound component signal corresponding to the first sound component CA within the reproduction frequency band of the speaker 3. Then, the first signal generator 41 forms a first signal SX including the first sound component CA by amplifying the first sound component signal by a first amplification factor. The second signal generator 42 forms a second sound component signal corresponding to the second sound component CB in a band lower than the reproduction frequency band of the speaker 3. Then, the second signal generator 42 forms a second signal SY including the second sound component CB by amplifying the second sound component signal by a second amplification factor.

[0117] The second mixing section 43 mixes the first signal SX and the second signal SY to form the test sound signal SA. According to such a speaker testing system 1, the first sound component CA and the second sound component CB can be freely changed.

[0118] Fifth Embodiment A speaker inspection method according to the fifth embodiment will be described. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description of the overlapping components will be omitted.

[0119] In the first embodiment, a system capable of inspecting the speaker 3 was described. In contrast, in the present embodiment, a method for inspecting the speaker 3 will be described.

[0120] The speaker inspection method includes first to fourth steps. In the first step, an output signal SB is formed by reproducing a test audio signal SA. The test audio signal SA can be reproduced by a regenerator. The regenerator is an amplifier. The regenerator has substantially the same structure as the regenerator unit 12. The test audio signal SA includes a first audio component CA within the reproduction frequency band of the speaker 3 and a second audio component CB in a band lower than the reproduction frequency band of the speaker 3. The configurations of the first audio component CA and the second audio component CB are the same as those in the first embodiment. In the second step, the output signal SB is output to the speaker 3. If the regenerator is connected to the speaker 3 via a signal wiring, the output signal SB is automatically output from the regenerator to the speaker 3 by turning on a switch that enables transmission of the output signal SB to the speaker 3. In the third step, the output sound SP output from the speaker 3 that has received the output signal SB is collected. Any method for collecting the sound may be used. In one example, the output sound SP is collected by placing a microphone near the speaker 3. Alternatively, the output sound SP may be collected by a smartphone that is placed near the speaker 3. In a fourth step, the state (e.g., deterioration state) of the speaker 3 is determined. Then, in the fourth step, the state (e.g., deterioration state) of the speaker 3 is determined based on the first sound component CA in the collected output sound SP. The determination in the fourth step may be performed by a personal computer or a computer located in the cloud.

[0121] With this configuration, in the test audio signal SA, the amplitude of the first audio component CA within the reproduction frequency band is smaller than the amplitude of the second audio component CB, thereby reducing the discomfort felt by people in the vicinity. Furthermore, by inputting the output signal SB of the test audio signal SA to the speaker 3, the speaker 3 can be vibrated at a magnitude substantially equivalent to the vibration of the speaker 3 when a predetermined signal within the reproduction frequency band is input to the speaker 3 at its rated input. In this way, the speaker 3 can be tested in a state that reproduces the vibration state of the speaker 3 when a predetermined signal within the reproduction frequency band is input to the speaker 3 at its rated input, thereby improving the accuracy of the test of the speaker 3.

[0122] Sixth Embodiment A storage medium for the test sound signal SA according to the sixth embodiment will be described. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description of the overlapping components will be omitted.

[0123] The storage medium for the test audio signal SA is a storage medium in which information relating to the test audio signal SA for testing the speaker 3 is stored.

[0124] There is no limitation on the type of storage medium. Examples of storage media include optical disks, magnetic disks, magnetic tapes, SD cards, hard disks, solid state drives (also known as SSDs), and USB memory sticks.

[0125] The test sound signal SA includes a first sound component CA within the reproduction frequency band of the speaker 3 and a second sound component CB in a band lower than the reproduction frequency band of the speaker 3. The configurations of the first sound component CA and the second sound component CB are the same as those in the first embodiment.

[0126] According to this configuration, in the test audio signal SA, the amplitude of the first audio component CA within the reproduction frequency band is smaller than the amplitude of the second audio component CB, thereby reducing discomfort to people around. Furthermore, by inputting the output signal SB of the test audio signal SA to the speaker 3, the speaker 3 can be vibrated at a magnitude substantially equivalent to the vibration of the speaker 3 when a predetermined signal within the reproduction frequency band is input to the speaker 3 at its rated input. In this way, the vibration state of the speaker 3 when a predetermined signal within the reproduction frequency band is input to the speaker 3 at its rated input can be reproduced. Therefore, by using information related to the test audio signal SA, the accuracy of the inspection of the speaker 3 can be improved.

[0127] <Modification> The above-described embodiments are merely examples of possible forms of the speaker testing system 1, the speaker testing method, and the storage medium for the test audio signal SA, and are not intended to limit the forms. The speaker testing system 1, the speaker testing method, and the storage medium for the test audio signal SA may take forms different from those illustrated in the above-described embodiments. Examples of such forms include forms in which part of the configuration of the embodiments is replaced, modified, or omitted, or forms in which new configuration is added to the embodiments. Modified examples of the embodiments are shown below.

[0128] The sound pickup unit 14 may have multiple sensitive units capable of picking up sounds. As shown in FIG. 14 , the sound collection unit 14 includes a high-sensitivity sound collection unit 49 and a low-sensitivity sound collection unit 48 having a lower sensitivity than the high-sensitivity sound collection unit 49. This configuration allows the selection of a device for collecting sound depending on the volume of the sound emitted from the speaker 3. For example, the high-sensitivity sound collection unit 49 can be selected when collecting a relatively quiet sound to measure its sound pressure, and the low-sensitivity sound collection unit 48 can be selected when collecting a relatively loud sound to measure its sound pressure. For example, when the determination unit 15 collects an output sound SP based on the output signal SB of the test sound signal SA to determine its sound pressure, the high-sensitivity sound collection unit 49 can be selected. When the determination unit 15 collects an output sound SP output by inputting a predetermined signal within the playback frequency band at a rated input and determines its sound pressure, the low-sensitivity sound collection unit 48 can be selected. The low-sensitivity sound collection unit 48 and the high-sensitivity sound collection unit 49 are preferably located close to each other so that they can both collect the output sound SP of the speaker 3.

[0129] Furthermore, when the sound collection unit 14 has a high-sensitivity sound collection unit 49 and a low-sensitivity sound collection unit 48 having a lower sensitivity than the high-sensitivity sound collection unit 49, the control unit 11 may perform the following operation. Specifically, the control unit 11 operates the low-sensitivity sound collection unit 48 when inspecting the speaker 3. With this configuration, it becomes difficult to pick up background noise, and the accuracy of the inspection of the speaker 3 can be improved.

[0130] Furthermore, the low-sensitivity sound pickup unit 48 and the high-sensitivity sound pickup unit 49 can be used to detect malfunctions of each other. That is, when a relatively small sound is collected by the high-sensitivity sound pickup unit 49, the low-sensitivity sound pickup unit 48 also collects the sound and measures the sound pressure at the same time. In this case, the sound pressure of the sound collected by the low-sensitivity sound pickup unit 48 will be a small value, but it is unlikely to be zero. Therefore, if the sound pressure measured by collecting sound by the high-sensitivity sound pickup unit 49 is sufficiently large, but the sound pressure measured by collecting sound by the low-sensitivity sound pickup unit 48 at the same time is below a predetermined threshold value close to zero, it is determined that the low-sensitivity sound pickup unit 48 may be malfunctioning. For example, in the second step S2, both the low-sensitivity sound pickup unit 48 and the high-sensitivity sound pickup unit 49 are turned on. In the eighth step S8, the sound pressure can be determined by the high-sensitivity sound pickup unit 49, and a malfunction of the low-sensitivity sound pickup unit 48 can also be determined. In the eighth step S8, when the sound pressure of the output sound SP picked up by the high-sensitivity sound pickup unit 49 exceeds the first threshold (i.e., even though it has been confirmed that a sufficient amount of output sound SP is being emitted), if the sound pressure of the output sound SP picked up by the low-sensitivity sound pickup unit 48 at the same time is below a predetermined threshold, it is determined that there is a high possibility that the low-sensitivity sound pickup unit 48 is malfunctioning.

[0131] <Reference technology> In the above embodiments, the second audio component signal is a signal in a frequency range lower than the playback frequency band of the speaker 3. However, in some cases, the second audio component signal may be a signal in a frequency range higher than the playback frequency band of the speaker 3. Speakers 3 include multi-way speakers, such as two-way and three-way speakers, which are suitable for reproducing a single audio signal over a wide frequency range, and tweeters, which are suitable for reproducing only high-frequency signals. While multi-way speakers 3 receive the audio signal directly from the sound source, tweeters generally receive only high-frequency audio signals separated by a high-pass filter. For this reason, it may be difficult to select a second audio component signal in a frequency range lower than the playback frequency band of the tweeter for tweeter inspection. In this case, it is preferable to select a second audio component signal in a frequency range higher than the playback frequency band of the tweeter (e.g., an ultrasonic band). As shown in FIG. 3 , even if the power of an input signal is the same, the higher the frequency of the signal, the smaller the amplitude of the diaphragm. Therefore, the magnitude of the second audio component CB, which is substantially equivalent to the vibration of the tweeter when a predetermined signal is input to the tweeter at its rated power, is greater than the rated value of the predetermined signal. For example, if the frequency of the second sound component CB is a frequency that vibrates only about 1 / 10 of the frequency of the predetermined signal even with the same power, the magnitude of the second sound component CB is set to 10 times the rated value. [Explanation of symbols]

[0132] CA...first sound component, CB...second sound component, SA...test sound signal, SB...output signal, SP...output sound, SX...first signal, SY...second signal, 1...speaker inspection system, 3...speaker, 11...control unit, 12...playback unit, 13...output unit, 14...sound pickup unit, 15...judgment unit, 31...first mixing unit, 41...first signal generator, 42...second signal generator, 43...second mixing unit, 48...low-sensitivity sound pickup unit, 49...high-sensitivity sound pickup unit.

Claims

1. A test audio signal for testing the audio status from the speaker of the emergency broadcast equipment, a first sound component within a reproduction frequency band of the speaker; a second sound component in a frequency band lower than the reproduction frequency band of the speaker, The first audio component is an audio component including at least a part of a frequency band constituting a signal sound reproduced when the emergency broadcast equipment makes an emergency broadcast, The frequency of the second sound component is lower than the minimum frequency of the first sound component and does not include a frequency band that constitutes the signal sound of the first sound component. Inspect audio signals.

2. The signal sound is a sound in the audible range. The test audio signal of claim 1.

3. The frequency of the second audio component is 40 Hz. The test audio signal of claim 1.

4. The amplitude of the first audio component is smaller than the amplitude of the second audio component. The test audio signal of claim 1.

5. The second audio component is The speaker is configured so that the magnitude of vibration of the speaker when an output signal formed by reproducing the test audio signal is input to the speaker is substantially equal to the magnitude of vibration of the speaker when a signal of the signal sound is input to the speaker at a rated input. The test audio signal according to any one of claims 1 to 4.

Images