JP5664431B2 - Speaker self-diagnosis device - Google Patents

Description

  The present invention relates to a speaker self-diagnosis device for diagnosing deterioration of a speaker unit.

  As the speaker unit is used, the sound quality is deteriorated due to fatigue of the cone edge or hardening of the damper. Particularly in a professional PA system, the speaker unit is often used at a power near the rated value, so that the deterioration is remarkable. In addition, in a professional PA system, it is absolutely necessary to avoid inconveniences such as the speaker unit breaking during use (during production) and no sound being produced.

  For this reason, it is desirable that the deterioration of the speaker unit can be diagnosed before use, but there has conventionally been no suitable diagnostic method.

JP 09-215085 A

  As an amplifier of a consumer audio device, there has been proposed an amplifier that emits a test tone and measures a frequency characteristic of an audio signal emitted from a speaker as disclosed in Patent Document 1, but the deterioration of the speaker unit itself is proposed. It was not a function to diagnose. That is, the technique of Patent Document 1 uses a microphone installed at a listening point (listening position) to measure the acoustic characteristics of the transmission system including the space from the speaker to the listening point, and to compensate for this characteristic. This is to set equalization. With this function, it is possible to determine whether the speaker is poorly connected or whether the polarity is normal or reverse as well as correcting the frequency characteristics, but it is difficult to measure the characteristics of the speaker unit itself. Moreover, the characteristic deterioration of the speaker unit is often difficult to judge only by the sound at the time of diagnosis.

  An object of the present invention is to provide a speaker self-diagnosis device capable of diagnosing characteristic deterioration of a speaker unit simply and reliably.

A first aspect of the present invention is a speaker self-diagnosis device housed in the same enclosure together with a speaker unit and an amplifier for supplying an amplified audio signal to the speaker unit. A spreading code generator for inputting a spreading code as an audio signal, a first microphone provided outside the enclosure for collecting the audio signal emitted by the speaker unit , and provided inside the enclosure The phase of the second microphone that picks up the sound signal emitted by the speaker unit, the sound signal picked up by the first microphone, and the sound signal picked up by the second microphone are mutually reversed. a correlation waveform detecting section for detecting a correlation waveform of the spreading code and the addition signal obtained by adding Te, the initial value of the correlation waveform of the sum signal and the spreading code A memory for storing, a correlation determination unit that compares the correlation waveform detected by the correlation waveform detection unit with the initial value, and a display unit that displays a comparison result of the correlation determination unit are provided. .

  The invention according to claim 2 is characterized in that the correlation waveform detecting unit detects a waveform obtained by converting a correlation waveform in the time domain into a frequency domain, and the memory stores an initial value of the waveform in the frequency domain. And

In the above invention, a network communication unit may be further provided that performs one or both of transmission of the comparison result of the correlation determination unit to another device and reception of the spread code generation instruction from the other device .

In the above invention, when detecting an ID setting unit in which an identification code of the own device is set, and a spread code modulated by the identification code of the own device from a voice signal picked up by the microphone, the correlation waveform detecting unit and A demodulator that detects a correlation waveform between the speech signal collected by the microphone and the spread code with respect to the correlation determination unit and compares the detected correlation waveform with the initial value; After the self-diagnosis operation is completed, a modulation unit that modulates the spreading code generated by the spreading code generator with an identification code of another device and outputs the modulated code to the amplifier may be further included .
According to a second aspect of the present invention, a spread code generator that inputs a spread code as the sound signal to an amplifier that supplies an amplified sound signal to the speaker unit, and an ID setting unit in which an identification code of the own device is set A microphone that picks up a voice signal, a correlation waveform detector that detects a correlation waveform between the voice signal picked up by the microphone and the spreading code, and a correlation between the voice signal picked up by the microphone and the spreading code A memory that stores an initial value of a waveform, a correlation determination unit that compares the correlation waveform detected by the correlation waveform detection unit with the initial value, a display unit that displays a comparison result of the correlation determination unit, and the microphone When a spread code modulated with the identification code of the own device is detected from the collected sound signal, the sound signal collected by the microphone with respect to the correlation waveform detection unit and the correlation determination unit and the spread code A demodulator that performs a self-diagnosis operation for detecting a correlation waveform and compares the detected correlation waveform with the initial value; and a spread code generated by the spread code generator after the self-diagnosis operation is completed And a modulation unit that modulates with the identification code of the device and outputs to the amplifier.
The correlation waveform detector may be a means for detecting a waveform obtained by converting a correlation waveform in the time domain into the frequency domain, and an initial value of the waveform in the frequency domain may be stored in the memory.

  According to the present invention, the correlation waveform at the time of shipment from the factory is stored as an initial value, and by comparing the current characteristic with this characteristic, it is possible to easily know the characteristic deterioration of the speaker, and sudden sound is emitted. Troubles such as disappearance can be prevented in advance. In addition, by using a spreading code such as an M-sequence as a speech signal for self-diagnosis, the self-diagnosis operation can be executed at a time and volume that is hardly noticed by the user.

Configuration diagram of a speaker according to an embodiment of the present invention Block diagram of the self-diagnosis device built into the speaker Diagram showing correlation waveform measured by self-diagnosis device The figure which shows the curve which Fourier-transformed the correlation value waveform of FIG. 3, and plotted in the frequency domain Flowchart showing self-diagnosis operation of self-diagnosis device and flowchart showing initial value storing operation at the time of improved shipment The figure which shows embodiment provided with the bass-reflex type enclosure Diagram showing a self-diagnosis device attached to the enclosure The figure which shows embodiment of the self-diagnosis apparatus provided with the network function Block diagram of a self-diagnosis device in which individual IDs are set Flowchart showing the operation of the self-diagnosis device of FIG.

  A speaker according to an embodiment of the present invention will be described with reference to the drawings. Hereinafter, in this specification, a speaker alone as a sound emitting device is referred to as a speaker unit, and a device in which the speaker unit and necessary circuits are housed in an enclosure (speaker box) is referred to as a speaker.

  FIG. 1 is a diagram showing a configuration of a speaker according to an embodiment of the present invention. FIG. 2 is a block diagram of a self-diagnosis device built in the speaker. FIG. 3 is a diagram showing a correlation waveform measured by the self-diagnosis device.

  This speaker 1 is an active speaker in which an amplifier (power amplifier) 11 is built together with a speaker unit 10 in an enclosure 15. The speaker 1 includes a self-diagnosis device 12 and a microphone 13. The self-diagnosis device 12 emits an M-sequence signal, which is a spread code, from the speaker unit 10, picks up the sound (sound wave) with the microphone 13 and measures the characteristics of the speaker unit 10. The deterioration or change of the speaker unit 10 is diagnosed by comparing with the stored initial value of the characteristic. Moreover, the speaker 1 is provided with the indicator 14 for displaying a diagnostic result.

  The speaker unit 10, the microphone 13, and the display device 14 are each attached to a baffle plate that is a front plate of the enclosure 15. The amplifier 11 amplifies the audio signal input from the outside and the M-sequence signal input from the self-diagnosis device 12 and supplies the amplified signal to the speaker unit 10.

  FIG. 2 is a block diagram of the self-diagnosis device 12. The self-diagnosis device 12 includes an M-sequence signal generator 20, a matched filter 21, a correlation waveform detection unit 22, a memory 23, and a correlation determination unit 24. These functional units operate as follows when diagnosing the characteristics of the speaker unit 10.

  The M-sequence signal generator 12 generates an M-sequence signal that is a spread code during the self-diagnosis operation and inputs it to the amplifier 11. The amplifier 11 amplifies the M-sequence signal and emits the sound from the speaker unit 10, and the sound is collected by the microphone 13. The sound collected by the microphone 13 is A / D converted and then input to the matched filter 21.

  The M-sequence signal generator 20 repeatedly generates an M-sequence signal for a predetermined period. As for the period of the M series, if the period is too short, the correlation value peak is small and it becomes difficult to determine synchronization, and the measurement accuracy deteriorates. On the other hand, if the length is too long, the sound emission time of the M-sequence signal becomes long and unpleasant, and the calculation load of the matched filter 21 increases. In consideration of these, the one having an appropriate period may be selected. For example, the sampling frequency is 48 kHz, the period is 511, and the chip rate is 2 samples. In this case, the time per cycle is about 22 ms, and even when the average of 10 cycles is measured, the sound generation time is about 220 ms, which is sufficiently short.

  The matched filter 21 is an FIR filter that uses the M-sequence signal generated by the M-sequence signal generator 20 as a filter coefficient, and outputs a correlation value between the sound collected by the microphone 13 and the M-sequence signal. This correlation value is input to the correlation waveform detector 22.

  The correlation waveform detection unit 22 detects a peak (synchronization point) that is the absolute value maximum point from the time-series data of the correlation value input from the matched filter 21, and a predetermined sample including this peak (for example, 1022 centered on the peak) Sample) time-series data is extracted as a correlation waveform. Since the M-sequence signal generator 20 repeatedly generates the M-sequence signal for a plurality of periods, a plurality of peaks also appear in the time-series data of the correlation values input from the matched filter 21. The correlation waveform detection unit 22 obtains a correlation waveform by cutting out and averaging time-series data of a predetermined sample including each peak (see FIG. 3). In FIG. 3, the solid line is the initial waveform, and the broken line is the correlation waveform at the time of high frequency deterioration.

  The memory 23 stores a correlation waveform (initial waveform) measured by the above procedure when the speaker 1 is shipped from the factory.

  The correlation determination unit 24 inputs the correlation waveform measured this time from the correlation waveform detection unit 22, reads the initial waveform from the memory 23, and compares the two. In this comparison, a difference is taken for each sample and the total value is used as a comparison result. If this comparison result is smaller than a preset threshold value, it is determined as normal. On the other hand, if the comparison result is equal to or greater than the threshold value, it is determined that the speaker unit 10 has deteriorated from the characteristics at the time of shipment. If no sound is produced due to the failure of the speaker unit 10, the output of the matched filter 21 does not have a waveform having a peak as shown in FIG. Can be determined).

  Then, the determination result is displayed on the display 14. An LED, an LCD, or the like can be applied to the display unit 14. When the display 14 is an LED, normal / abnormal may be displayed by display color or lighting / flashing. Further, when the display 14 is an LCD matrix display, it is only necessary to indicate whether the display 14 is normal or abnormal by text.

  In the embodiment described above, the presence or absence of deterioration of the speaker unit 10 is determined by comparing the correlation waveforms in the time domain. If the processing capability of the self-diagnosis device 12 (correlation determination unit 22) is sufficient, the frequency characteristics of the speaker unit 10 as shown in FIG. 4 may be obtained by Fourier transforming the correlation waveform. In this case, the memory 23 stores the frequency characteristics (initial characteristics) of the speaker unit 10 at the time of shipment from the factory. By comparing the frequency characteristics, which are waveforms in the frequency domain, it is also possible to strictly evaluate and display how much the characteristics change for each frequency band.

  FIG. 4 is a graph in which the correlation value waveform of FIG. 3 is Fourier transformed and plotted in the frequency domain. In this way, by converting the correlation waveform into a characteristic curve in the frequency domain, the difference between the frequency characteristics at the time of shipment and high frequency degradation becomes clear. That is, the difference in frequency characteristics can be determined by the difference in correlation value waveform. If there is a margin in processing load, the correlation waveform can be subjected to Fourier transform to strictly evaluate and display what band has deteriorated from the time of shipment.

  Spread codes such as M-sequence signals include all frequency bands and have high noise immunity, so accurate measurement is possible if they are played with a small sound, and a loud impulse sound or a long sweep sound is produced. It is not necessary, the burden on the speaker unit is small, and it is not uncomfortable for hearing.

  FIG. 5A shows a flowchart of the self-diagnosis process of the self-diagnosis apparatus 12. The self-diagnosis process is executed automatically when the power is turned on or in response to a manual operation by a staff member. First, the spread code generator 20 generates an M-sequence signal and inputs it to the amplifier 11 (S1). As a result, the M-sequence signal is emitted as sound from the speaker unit 10, and the sound is picked up by the microphone 13 and re-input to the matched filter 21 of the self-diagnosis device 12 as a time-series sound signal. The matched filter 21 outputs the correlation value between the input audio signal and the M-sequence signal in time series (S2). Note that the processes of S1 and S2 are not executed sequentially but are executed in parallel.

  The correlation waveform detection unit 22 obtains a correlation waveform based on the correlation value output from the matched filter 21 (S3). And the correlation determination part 24 determines the state of the speaker unit 10 by comparing this calculated | required correlation waveform with the initial waveform memorize | stored in the memory 23 (S4). If the speaker unit 10 is abnormal (deteriorated) as a result of the determination (YES in S5), the display unit 14 displays an abnormality (S6). If there is no abnormality (NO in S5), the display unit 14 is normal. A message is displayed (S7).

  When comparing the frequency characteristics obtained by Fourier transforming the correlation waveforms, Fourier transform processing is performed after S3, and the initial characteristics stored in the memory 23 and the frequency characteristics measured this time are compared in S4. .

  FIG. 5B is a flowchart showing the initial waveform measurement operation performed at the time of factory shipment. First, the spread code generator 20 generates an M-sequence signal and inputs it to the amplifier 11 (S11). As a result, the M-sequence signal is emitted as sound from the speaker unit 10, and the sound is picked up by the microphone 13 and re-input to the matched filter 21 of the self-diagnosis device 12 as time-series sound data. The matched filter 21 outputs the correlation value between the input voice data and the M-sequence signal in time series (S12). The correlation waveform detector 22 obtains a correlation waveform based on the correlation value output from the matched filter 21 (S13). Then, the obtained correlation waveform is stored in the memory 23 (S14).

  FIG. 6 shows another embodiment of the speaker of the present invention. This embodiment is an example in which a second microphone is provided inside a bass reflex type enclosure. In this embodiment, the same components as those in the embodiment shown in FIG. 1 and FIG.

  In FIG. 6A, the enclosure 35 is a bass reflex type, and a bass reflex port 35A is opened in a baffle plate. The first microphone 13 is provided outward from a hole formed in the baffle plate of the enclosure 35. On the other hand, the second microphone 33 is provided inside the enclosure 35. The first microphone 13 may be provided outside the baffle plate without making a hole in the baffle plate. Moreover, it is preferable that the first microphone 13 and the second microphone 33 are provided at a substantially equal distance from the speaker unit 10. In addition to the configuration of the self-diagnosis device 12 illustrated in FIG. 2, the self-diagnosis device 32 includes a calculation unit illustrated in FIG. The calculation unit is inverted by the inverter 36 that inverts the phase of the audio signal picked up by the second microphone 33 and the audio signal picked up by the first microphone 13 and the inverter 36 (the second microphone 33 collects the sound). It has an adder 37 for adding the sound signals. The addition output of the adder 37 is input to the matched filter 21.

  The two microphones 13 and 33 collect the sound output from the speaker unit 10 in the normal phase and the reverse phase, respectively. On the other hand, disturbances such as noise and vibration applied from the outside of the speaker unit 10 are collected in the same phase by both the first microphone 13 and the second microphone 33. Therefore, as shown in FIG. 6B, if the phases of one of the two audio signals collected by the first microphone 13 and the second microphone 33 are inverted and added together. In-phase disturbances are canceled because they are reversed to the opposite phase, and M-sequence signals picked up in the opposite phase as speaker sounds are reversed to the same phase. Correlation values can be obtained.

  Thus, in the case of an enclosure that is not hermetically sealed, a second microphone is installed near the speaker unit inside the enclosure, and is inverted and added to the collected sound signal of the first microphone installed toward the outside of the enclosure. Thus, in addition to using a spreading code for measurement sound, it is possible to further reduce the influence of disturbance.

  FIG. 7 is a diagram illustrating an example in which an external unit 4 for self-diagnosis is connected to a speaker 3 that does not include an amplifier but includes only the speaker unit 10. In this embodiment, the same components as those in the embodiment shown in FIG. 1 and FIG. In this embodiment, the audio signal output from the audio amplifier is supplied to the speaker unit 10 via the selector 36 of the external unit 4. The external unit 4 includes an amplifier 11, a self-diagnosis device 12, a microphone 13, a display 14 and a selector 36. The output terminal of the selector 36 is connected to the speaker unit 10 of the speaker 2. The two input terminals of the selector 36 have a first terminal connected to the audio signal input terminal and a second terminal connected to the amplifier 11. During normal use of the speaker 2, the selector 36 is connected to the first input terminal side, and the audio signal output from the audio amplifier is supplied to the speaker unit 10. At the time of self-diagnosis of the speaker unit 10, the selector 36 is switched to the second input terminal side, and the M-sequence signal output from the self-diagnosis device 12 (M-sequence signal generator 20) and amplified by the amplifier 11 is the speaker unit. 10 is supplied.

  Thereby, the self-diagnosis of the speaker unit 10 of the speaker 3 which does not incorporate an amplifier becomes possible. It is preferable that the position of the external unit 4 or at least the microphone 13 is fixed with respect to the speaker 3 so that the sound collecting position of the sound of the speaker unit 10 by the microphone 13 does not change every measurement.

  FIG. 8 is a diagram illustrating an example in which a network function is provided in the speaker illustrated in FIGS. 1 and 2. In this embodiment, the same components as those in the embodiment shown in FIG. 1 and FIG. The speaker 5 of this embodiment includes a network module 17 in addition to the configuration of the speaker 1 shown in FIG. The network module 17 is connected to the self-diagnosis device 12. The network module 17 is connected to an external network such as the Internet or a LAN. A server computer for managing the speaker 5 and other speakers having the same configuration are connected to the network.

  By performing a self-diagnosis operation when a self-diagnosis is instructed via the network, even in a PA system having a plurality of speakers, a staff member can be applied to each speaker away from the mixing console or the like. By sequentially issuing instructions, each speaker can perform a self-diagnosis individually.

  Further, since the self-diagnosis device 12 is connected to the server computer via the network, the self-diagnosis result can be transmitted not only to the display 14 of the main body but also to the server computer. The server computer is installed, for example, in a contractor maintenance facility or an equipment management department. Thereby, maintenance can be speeded up.

  In addition, when a plurality of speakers are installed, a unique ID is set for each speaker, and the ID is transmitted using sound, so that a plurality of speakers can be made to perform a self-diagnosis operation individually. . For example, “A certain speaker emits an M-sequence signal modulated by the ID of the next speaker after performing a self-diagnosis. After the next speaker receiving this M-sequence signal performs a self-diagnosis, the next By repeating the operation of “sounding an M-sequence signal modulated with the ID of the speaker”, it is possible to cause a plurality of speakers to sequentially execute a self-diagnosis operation without using a network or the like. For the modulation of the M-sequence signal by the ID, for example, as disclosed in WO2010 / 016589A1 by the applicant, a method of phase-modulating the M-sequence signal for each period based on the symbol string representing the ID may be adopted. .

  FIG. 9 is a configuration diagram of the self-diagnosis device 40 provided in the speaker 1 in which the ID is set. In this embodiment, the same components as those in the embodiment shown in FIG. The matched filter 21, the correlation waveform detection unit 22, the memory 23, and the correlation determination unit 24 have the same configuration as that of the self-diagnosis device 12 shown in FIG. The M-sequence signal generator 20 has the same configuration. In this embodiment, a demodulator 25, a modulator 26, and a DIP switch 27 are further provided.

  The ID of this speaker is set in the DIP switch 27 by an attendant. When there is one speaker, an ID of 0 is set for the speaker. When there are a plurality of speakers, a numerical value from 0 to a serial number is set for each speaker. The ID set in the DIP switch 27 is read by the demodulator 25 and the modulator 26.

  The matched filter 21 receives an audio signal picked up by the microphone 13. The correlation value detected by the matched filter 21 is output to the correlation determination unit 22 and the demodulator 25. The sound signal picked up by the microphone 13 includes not only the sound emitted by the speaker unit 10 of the device itself but also the sound emitted by the speaker unit of another speaker.

  The demodulator 25 detects the phase of the peak of the input M-sequence signal based on the correlation value input from the matched filter 21, and demodulates the ID superimposed on the M-sequence signal based on the phase of this peak. . If this ID is the ID of the own device set by the DIP switch 27, the modulator 26, the correlation waveform detecting unit 22, the correlation so as to start the self-diagnosis operation on the basis of the self-diagnosis order of the own device. The determination unit 24 and the like are controlled.

  The self-diagnosis operation is as described above, and the M-sequence signal generated by the M-sequence signal generator 20 is output to the amplifier 11 as it is without being modulated via the modulator 26.

  When the self-diagnosis operation of the own device is completed, the demodulator 25 modulates the M-sequence signal to the modulator 26 with “ID + 1 of own device” which is the ID of the next speaker and outputs the modulated signal. To instruct. By emitting the M-sequence signal modulated with “ID of own device” from the speaker unit 10, it is possible to instruct the next speaker to perform a self-diagnosis operation. Note that even if the last speaker emits an M-sequence signal modulated with “ID of own device + 1”, there is no speaker corresponding to this ID, but no speaker responds to the sound emission of this ID. Since a series of self-diagnosis operations are finished as they are, it is not necessary to request another operation for the last speaker.

  FIG. 10 is a flowchart showing the operation of the self-diagnosis device 12 for one speaker. In the case of a PA system composed of a plurality of speakers, the self-diagnosis device for each speaker performs this operation. When the operation starts, it is first determined whether or not the ID of its own device is 0 (S20). If the ID of the own device is 0 (YES in S20), the self-diagnosis operation is executed assuming that the device is the device that first executes the self-diagnosis operation (S22).

  If the ID of the own device is not 0 (NO in S20), the process waits until the ID of the own device is received by voice (S21). If the audio signal picked up by the microphone 13 includes an M-sequence signal modulated by the ID of the own device, that is, if the ID of the own device is received (YES in S21), the self-diagnosis operation is executed. (S22). After the self-diagnosis operation is completed, the operation of the M-sequence signal modulated with the ID “own device ID + 1” is completed for the amplifier 11 (S23).

  The M-sequence signal modulated with the ID “own device ID + 1” is amplified by the amplifier 11 and emitted from the speaker unit 10. The speaker identified by the ID “own device ID + 1” that has received the sound next starts a self-diagnosis operation.

  In the above embodiment, the ID of each speaker is not limited to a continuous numerical value. It suffices that the self-diagnosis device for each speaker can be set so as to sequentially emit the ID of the next speaker after the self-diagnosis operation.

  Also, in the embodiments of FIGS. 1 to 10, the spreading code is not limited to the M-sequence signal.

DESCRIPTION OF SYMBOLS 1 Speaker 10 Speaker unit 11 Amplifier 12 Self-diagnosis apparatus 13 Microphone 14 Display 20 M series signal generator 21 Matching filter 22 Correlation waveform detection part 23 Memory 24 Correlation determination part

Claims (6)

A speaker unit and a self-diagnosis device for a speaker housed in the same enclosure together with an amplifier that supplies an amplified audio signal to the speaker unit ,
To the amplifier, the spreading code generator for inputting a spread code as the speech signal,
A first microphone that is provided toward the outside of the enclosure and collects an audio signal emitted by the speaker unit ; and a first microphone that is provided inside the enclosure and collects an audio signal emitted by the speaker unit. Two microphones ,
Correlation waveform detection for detecting a correlation waveform between an addition signal obtained by adding the phase of the audio signal picked up by the first microphone and the sound signal picked up by the second microphone with the phases inverted, and the spread code And
A memory for storing an initial value of a correlation waveform between the addition signal and the spreading code;
A correlation determination unit that compares the correlation waveform detected by the correlation waveform detection unit with the initial value;
A display unit for displaying a comparison result of the correlation determination unit;
A self-diagnosis device for a speaker comprising The correlation waveform detector is means for detecting a waveform obtained by converting a correlation waveform in the time domain into a frequency domain,
The speaker self-diagnosis device according to claim 1, wherein the memory stores an initial value of a waveform in a frequency domain. 3. The network communication unit according to claim 1, further comprising a network communication unit that performs one or both of transmitting the comparison result of the correlation determination unit to another device and receiving the generation instruction of the spread code from the other device. Speaker self-diagnosis device. An ID setting unit in which an identification code of the own device is set;
When a spread code modulated with an identification code of the device is detected from a sound signal picked up by the microphone, the sound signal picked up by the microphone and the spread to the correlation waveform detection unit and the correlation determination unit A demodulator for detecting a correlation waveform with a code and performing a self-diagnosis operation for comparing the detected correlation waveform with the initial value;
After the self-diagnosis operation is completed, a modulation unit that modulates a spreading code generated by the spreading code generator with an identification code of another device and outputs the modulated code to the amplifier;
The speaker self-diagnosis device according to claim 1 or 2 , further comprising: A spread code generator that inputs a spread code as the sound signal to an amplifier that supplies the amplified sound signal to the speaker unit;
An ID setting unit in which an identification code of the own device is set;
A microphone that picks up the audio signal;
A correlation waveform detection unit for detecting a correlation waveform between the voice signal picked up by the microphone and the spread code;
A memory for storing an initial value of a correlation waveform between the voice signal collected by the microphone and the spread code;
A correlation determination unit that compares the correlation waveform detected by the correlation waveform detection unit with the initial value;
A display unit for displaying a comparison result of the correlation determination unit;
When a spread code modulated with an identification code of the device is detected from a sound signal picked up by the microphone, the sound signal picked up by the microphone and the spread to the correlation waveform detection unit and the correlation determination unit A demodulator for detecting a correlation waveform with a code and performing a self-diagnosis operation for comparing the detected correlation waveform with the initial value;
After the self-diagnosis operation is completed, a modulation unit that modulates a spreading code generated by the spreading code generator with an identification code of another device and outputs the modulated code to the amplifier;
A self-diagnosis device for a speaker comprising   The correlation waveform detector is means for detecting a waveform obtained by converting a correlation waveform in the time domain into a frequency domain,
  The memory stores initial values of frequency domain waveforms.
  The self-diagnosis device for a speaker according to claim 5.

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