JP5946057B2 - SOUND DEVICE, RESONANT SOUND DETECTING METHOD, RESONANT SOUND DETECTING PROGRAM, AND MEDIUM CONTAINING RESONANT SOUND DETECTING PROGRAM - Google Patents

Description

The present invention relates to, for example, an acoustic device attached to a structure such as an automobile door, a resonance sound detection method for detecting a buzzing sound (resonance sound) generated when a speaker connected to the acoustic device is vibrated, and a resonance sound. The present invention relates to a recording medium in which a detection program and the resonance sound detection program are recorded so as to be readable by a computer.

  In the above-described acoustic apparatus to which the conventional speaker is connected, the speaker is attached to a structure such as an automobile door. At this time, if the volume from the speaker is increased or the screwing to the speaker structure is loose, the structure will resonate with the vibration of the speaker, resulting in a noise (resonance sound). was there. Therefore, in order to solve this problem, conventionally, a portion of the structure that resonates with the vibration of the speaker is searched, and a vibration isolating material is attached to the portion to prevent resonance of the structure. It has been considered to reduce sound (for example, Patent Document 1).

  However, the conventional method of attaching a vibration isolator has a problem that it is necessary to search for a resonating portion, which requires much time and labor.

JP-A-9-37371

This invention makes it an example of a subject to cope with such a problem. That is, the present invention is, for example, an acoustic device capable and Turkey detecting the frequency bands kink sound (resonance sound) occurs, the resonance sound detection method, providing a medium recording resonance sound detection program, and the resonance sound detection program The purpose is to do.

In order to solve the above-described problem, an acoustic device according to claim 1 is configured to measure a resonance sound from a measurement unit that measures a harmonic distortion of a current flowing through a connected speaker, and a frequency characteristic of the measured harmonic distortion. There is characterized in that and a frequency band detector for detecting a frequency band generated.

Resonant sound detecting method according to claim 8, a resonance sound detection method used in the acoustic apparatus, a measuring step of measuring the harmonic distortion of the current flowing through the speaker connected to the sound device, the measurement And a frequency detection step of detecting a frequency band in which a resonance sound is generated from the frequency characteristics of the harmonic distortion that has been generated.

The resonance sound detection program according to claim 9 is caused to flow through the speaker by causing a computer of an acoustic device including a measurement unit that measures harmonic distortion of a current flowing through a connected speaker to control the measurement unit. the harmonic distortion of the current is measured, the measured resonance noise from the frequency characteristics of the harmonic distortion was is characterized and Turkey to detect the frequency band generated.

It is a block diagram which shows the audio equipment concerning one Example of this invention. It is a figure for demonstrating the installation position of the speaker shown in FIG. It is a graph which shows the 2nd order and 3rd order distortion of the admittance of a speaker at the time of tightening a screw firmly and attaching a speaker to a door, and the current which flows into a speaker. It is a graph which shows the admittance of a speaker at the time of loosening a screw a little and attaching the speaker to the door, and the secondary distortion of the electric current which flows into a speaker. It is a graph which shows the admittance of a speaker at the time of loosening a screw a little and attaching the speaker to the door, and the secondary distortion of the electric current which flows into a speaker. It is a graph which shows the 2nd order and 3rd order distortion of the admittance of the speaker when the screw is considerably loosened and the speaker is attached to the door, and the current flowing through the speaker. It is a flowchart which shows the resonance sound reduction process sequence of a control part.

  Hereinafter, an audio device according to an embodiment of the present invention will be described. As a result of diligent search to reduce the resonance sound, the present inventor has focused on the fact that the admittance of the speaker and the harmonic distortion of the current flowing through the speaker are disturbed in the frequency band where the chatter sound (resonance sound) is generated. In the acoustic device according to an embodiment of the present invention, the measurement unit measures the harmonic distortion of the current flowing through the speaker, and the frequency band detection unit generates the resonance sound from the frequency characteristic of the measured harmonic distortion. The band is detected, and the attenuating means attenuates the frequency band component detected by the frequency band detecting means in the reproduction signal reproduced by the speaker. For this reason, since the frequency band component in which the resonance sound such as the noise is generated is attenuated, the noise can be reduced without searching for the portion of the structure that is resonating with the vibration of the speaker. Generation of sound can be reduced.

  Further, the measurement unit may measure the admittance of the speaker, and the frequency band detection unit may detect a frequency band in which a resonance sound is generated from both frequency characteristics of the measured admittance and harmonic distortion. Thereby, the frequency band in which the resonance sound is generated can be detected more accurately.

  Further, the attenuating means may be constituted by a band elimination filter that removes the frequency band component detected by the frequency band detecting means. As a result, the frequency band in which the resonance sound is generated can be reliably removed, and the frequency band in which the resonance sound is generated can be more reliably reduced, thereby preventing the generation of the resonance sound.

  Further, the measurement means may perform measurement based on the current flowing through the measurement resistance when the measurement resistance is connected in series to the speaker by the switching means. Thereby, when not measuring, since it becomes unnecessary to connect the resistance for measurement to the speaker in series, it is possible to prevent deterioration of sound quality due to the resistance for measurement.

  In addition, a resonance sound attenuation method according to an embodiment of the present invention measures harmonic distortion of a current flowing in a speaker, detects a frequency band in which resonance sound is generated from the measured harmonic distortion frequency characteristics, and The frequency band component detected in the reproduction signal reproduced by the above is attenuated. For this reason, since the frequency band component in which the resonance sound such as the noise is generated is attenuated, the noise can be reduced without searching for the portion of the structure that is resonating with the vibration of the speaker. Generation of sound can be reduced.

  According to another aspect of the present invention, there is provided a resonance sound reduction program that causes a computer of an acoustic device including a measurement unit that measures harmonic distortion of a current flowing through a connected speaker to control the measurement unit, and Measures the harmonic distortion of the current flowing through the frequency, detects the frequency band where the resonance sound is generated from the measured harmonic distortion frequency characteristics, and attenuates the detected frequency band component of the reproduced signal reproduced by the speaker . For this reason, since the frequency band component in which the resonance sound such as the noise is generated is attenuated, the noise can be reduced without searching for the portion of the structure that is resonating with the vibration of the speaker. Generation of sound can be reduced.

  Further, the above-described resonance noise reduction program may be stored in a computer-readable recording medium. In this way, the program can be distributed as a single unit in addition to being incorporated in the apparatus, and upgrading and the like can be easily performed.

  Hereinafter, an embodiment of an acoustic device of the present invention will be described with reference to FIGS. The acoustic device 1 shown in FIG. 1 is mounted on a vehicle, for example, and is connected to a speaker 2 attached to a door 9 of the vehicle. As shown in FIG. 1, the acoustic device 1 includes an amplifier unit 3 that amplifies a signal input to the speaker 2, a measurement resistor R for measuring the admittance of the speaker 2, its second-order and third-order distortion, and measurement. Switching unit 4 as switching means for switching between a state in which the resistor R is connected in series to the speaker 2 and a state in which the resistor R is not connected in series to the speaker 2, a switching drive unit 5 that drives the switching unit 4, and a measurement resistor R Frequency characteristic measuring unit 6 as a measuring means for measuring admittance, second-order and third-order distortion from a voltage drop occurring in the signal, a control unit 7 comprising a computer for controlling the entire acoustic device 1, and signal processing of the reproduction signal And a DSP unit 8 composed of a computer that performs the above.

  As shown in FIG. 2, the speaker 2 includes a main body 21 and an annular mounting flange 22 for mounting the speaker 2 to a vehicle door 9. The main body portion 21 includes a diaphragm, an edge, a voice coil bobbin around which a voice coil is wound, a vibration body (not shown) having a damper, and a magnet, a plate, And a magnetic circuit (not shown) having a yoke or the like. When the speaker 2 is supplied with an audio current to a voice coil attached to the diaphragm, an electromagnetic force (Lorentz force) acts on the voice coil, and the diaphragm vibrates to generate sound.

  The door 9 to which the speaker 2 is attached includes, for example, an outer panel 91 and an inner panel 92 made of sheet metal, an attachment portion 93 for attaching the speaker 2 to the door 9, and a door trim 94 made of synthetic resin. I have. The outer panel 91 is disposed on the vehicle exterior side, the inner panel 92 is disposed on the passenger cabin side, the outer edge portions are overlapped with each other, and the center portions are attached to each other with a space therebetween.

  The inner panel 92 is provided with a through hole 92 a for accommodating the speaker 2. The attachment portion 93 is provided in an annular shape along the periphery of the through hole 92a provided in the inner panel 92, and is screwed to the periphery of the through hole 92a. The mounting flange 22 of the speaker 2 is overlapped with the annular mounting portion 93. At this time, the mounting flange 22 and the mounting portion 93 that are overlapped with each other are screwed in a state where the main body portion 21 of the speaker 2 is accommodated between the panels 91 and 92 through the through-hole 92a of the inner panel 92, whereby the speaker 2 is attached to the door 9. Thereafter, the door trim 94 is overlaid on the inner panel 92 and fixed.

  Next, before explaining the continuation of the configuration of the acoustic device 1, the principle of the resonance sound reducing method of the present invention will be described below with reference to FIGS. When the present inventor firmly tightens the screw and attaches the speaker 2 to the door 9, when the speaker 2 is attached to the door 9 by loosening the screw a little, a medium level of noise (resonance sound) is generated When the speaker 2 is attached to the door 9 by loosening the screws considerably, the extraordinary level of noise is generated. The admittance of the speaker 2 in each frequency band of 20 Hz to 20000 Hz and the harmonics of the current flowing through the speaker 2. Second and third order distortions were measured. The results are shown in FIGS.

  3 to 6, the admittance can be obtained from the current flowing through the speaker 2 when a measurement signal made of, for example, a sine wave is supplied to the speaker 2. The second-order distortion is a second-order component riding on the current flowing through the speaker 2, and is obtained by extracting a frequency component twice the measurement signal from the current flowing through the speaker 2. That is, in FIG. 3 to FIG. 6, for example, the second-order distortion plotted corresponding to 100 Hz flows to the speaker 2 when a measurement signal of 100 Hz is supplied to the speaker 2 and the speaker 2 is vibrated at 100 Hz. A 200 Hz component is extracted from the current and plotted as a secondary distortion at 100 Hz. The third-order distortion is a third-order component riding on the current flowing through the speaker 2, and a frequency component that is three times the measurement signal is extracted from the current flowing through the speaker 2 and plotted. That is, in FIG. 3 to FIG. 6, for example, the third-order distortion plotted corresponding to 100 Hz is a current that flows through the speaker 2 when a measurement signal of 100 Hz is supplied to the speaker 2 and the speaker 2 is vibrated at 100 Hz. The 300 Hz component is extracted from the graph and plotted as the third-order distortion at 100 Hz.

  As shown in FIG. 3, the admittance and the speaker 2 are surrounded by an alternate long and short dash line at a frequency at which a structure around the door 9 or the like resonates even though the screw is firmly tightened, but no sound is generated. It was found that the second-order and third-order distortions of the current flowing in the riot were unclear. As shown in FIG. 4 to FIG. 6, the admittance, second-order, and third-order distortion increase when the chatter noise occurs, and the admittance, second-order, third-order distortion increases as the chatter sound increases. It has been found that the rampage of will also increase. Therefore, in the acoustic device 1 of the present embodiment, for example, when the speaker 2 is installed, the frequency characteristics of the admittance, the second order, and the third order distortion of the speaker 2 are obtained, and the chatter sound is generated in a band in which the frequency characteristics are greatly violated. The band is specified, and when the playback signal is played back by the speaker 2 thereafter, the band specified from the playback signal is cut and supplied to the speaker 2.

  Next, returning to the configuration of the acoustic apparatus 1 of the present embodiment, the amplifier unit 3 receives measurement signals and reproduction signals output from the control unit 7 and the DSP unit 8 described later, and amplifies these signals. And input to the speaker 2. The measurement resistor R is a resistor for measuring the current flowing through the speaker 2 in order to obtain admittance, second order, and third order distortion. The switching unit 4 is composed of, for example, a relay and the like. The switching unit 4 includes a terminal T1 connected to the amplifier unit 3, a terminal T21 connected to the + side of the speaker 2 via the measurement resistor R, and a measurement resistor R. There are provided a terminal T22 directly connected to the + side of the speaker 2 without intervention, and a contact S for switching the connection of the terminal T1 between the terminals T21 and T22. In the switching unit 4, when the contact S is connected to the terminal T22, the measurement resistor R is connected in series to the speaker 2, and when the contact S is connected to the terminal T21, the measurement resistor R is connected to the speaker 2. It will not be connected in series. The switching drive unit 5 switches the switching unit 4 in accordance with a switching control signal from the control unit 7.

  The frequency characteristic measurement unit 6 measures the voltage drop generated in the measurement resistor R when the measurement resistor R is connected in series to the speaker 2, and the admittance, the second order, and the third order of the speaker 2 are measured from the measured voltage drop. The frequency characteristic of the distortion is measured, and the result is output to the control unit 7. Specifically, while the control unit 7 outputs a measurement signal whose frequency is swept between 100 Hz to 10000 Hz (not including the resonance frequency of the speaker 2) to the amplifier unit 3, for example. The frequency characteristic measuring unit 6 measures a voltage drop generated in the measurement resistor R at each frequency. If the amplitude of the measurement signal is made constant, this voltage drop is a value corresponding to the current flowing through the speaker 2 and a value corresponding to the admittance of the speaker 2. The voltage drop that occurs in Further, the frequency characteristic measuring unit 6 extracts only the second order component and the third order component from the frequency characteristic of the voltage drop corresponding to the measured current flowing through the speaker 2 using a filter or the like, and extracts the second order distortion, the third order. Obtain the frequency characteristics of the distortion.

  Next, the control unit 7 functions as a frequency band detection unit, and detects a frequency band in which the frequency characteristics of the admittance, the second order, and the third order distortion measured by the frequency characteristic measurement unit 6 are large as a band in which the chatter sound is generated. . As a band detection method, for example, the frequency characteristics of admittance, second-order, and third-order distortion are differentiated, and the slope (change rate) of admittance, second-order, and third-order distortion with respect to frequency is obtained. For example, it is conceivable to detect a band in which a ramp is generated in a narrow frequency band in which the slope alternately becomes + or −. In this way, when a region where a rattling sound is generated is detected, in the example illustrated in FIGS. 3 to 6, a band surrounded by a two-dot chain line is detected as a band where the chatter sound is generated.

  When the control unit 7 detects a band in which a rattling sound is generated, the control unit 7 supplies it to the DSP unit 8. When a band in which a rattling sound is generated is supplied, the DPS unit 8 stores the band in which the rattling sound is generated in a memory (not shown). Thereafter, the DSP unit 8 functions as an attenuating means. When a reproduction signal is input, the DSP unit 8 applies an equalizer such as a banded filter (band elimination filter) to the band where the reproduction sound is generated from the reproduction signal, and the The generated band is attenuated and output to the amplifier unit 3.

  Details of the operation of the acoustic device 1 described in the above outline will be described with reference to FIG. FIG. 7 is a flowchart showing the resonance sound reduction processing procedure of the control unit 7. For example, after the acoustic device 1 is attached to the door 9, when an operation unit (not shown) is operated, the control unit 7 starts a resonance noise reduction process.

  In the resonance noise reduction process, the control unit 7 first controls the switching drive unit 5 to connect the contact S of the switching unit 4 to the terminal T22 (step S1). As a result, the measurement resistor R is connected in series to the speaker 2. Next, the control unit 7 supplies a measurement signal whose frequency sweeps between, for example, 100 Hz to 10000 Hz to the amplifier unit 3 and controls the frequency characteristic measurement unit 6 to control the admittance of the speaker 2, its second order and third order. A frequency characteristic measurement process (process) for measuring distortion is performed (step S2). The controller 7 sweeps the measurement signal three times in order to measure the admittance and its second and third order distortions. After that, the frequency characteristic measuring unit 6 waits for the frequency characteristics of the admittance, the second-order and third-order distortions to be supplied (Y in step S3), and the chatter sound is determined from the frequency characteristics of the admittance, the second-order and third-order distortions. A frequency band detection process is performed to detect a frequency band in which occurrence occurs (step S4).

  Thereafter, the control unit 7 supplies the DSP 8 with a frequency band in which the detected noise is generated (step S5), and then controls the switching drive unit 5 to connect the contact S of the switching unit 4 to the terminal T21. (Step S6), and the process ends. When the contact S is switched to the terminal T21, the measurement resistor R is not connected in series to the speaker 2. As described above, the DSP unit 8 stores the band in which the buzzing sound is generated in a memory (not shown) when the band in which the buzzing sound is generated is supplied, and when the reproduction signal is input thereafter, the reproduction signal is stored. Then, an equalizer such as a banded filter (band elimination filter) is applied to the band where the chatter noise is generated, and the band where the chatter noise is generated is attenuated and output to the amplifier unit 3.

  According to the acoustic device 1 described above, the frequency characteristic measurement unit 6 measures the second-order and third-order distortion frequency characteristics of the speaker 2, and the control unit 7 determines the frequency characteristics from the measured second-order and third-order distortion frequency characteristics. The frequency band in which sound (resonant sound) is generated is detected, and the DSP unit 8 attenuates the frequency band component detected by the control unit 7 in the reproduction signal reproduced by the speaker 2. For this reason, since the frequency band component in which resonance sounds, such as a buzzing sound, are attenuated, it is possible to reduce the buzzing sound without searching for the portion of the structure (door 9) that resonates with the vibration of the speaker 2. Can be easily reduced.

  Further, according to the acoustic device 1 described above, the frequency characteristic measurement unit 6 also measures the frequency characteristic of the admittance of the speaker 2, and the control unit 7 measures the frequency characteristics of both the measured admittance and the second-order and third-order distortion. To detect the frequency band in which the sound is generated. For this reason, it is possible to detect the frequency band in which the chatter sound is generated more accurately.

  In addition, according to the acoustic device 1 described above, since the DSP unit 8 applies an equalizer having a function of a banded filter, the frequency band in which the trumpet sound is generated is surely removed, and the thorn sound is more reliably generated. The frequency band can be reduced to prevent the generation of resonance sound.

  In addition, according to the Example mentioned above, although the audio apparatus 1 was mounted in the vehicle, this invention is not limited to this. For example, if the speaker 2 is attached to a structure such as a wall of a building such as a house or a store, a rattling noise is generated. Therefore, the present invention can also be applied to that case.

  Further, according to the embodiment described above, the frequency characteristic measuring unit 6 also measures the admittance of the speaker 2, but the present invention is not limited to this. For example, only the frequency characteristics of the second order distortion of the current flowing through the speaker 2 may be measured, or only the frequency characteristics of the second and third order distortions may be measured to detect the frequency band where the chatter sound is generated. May be.

  Further, according to the above-described embodiment, the frequency characteristic measuring unit 6 measures the second-order and third-order distortions, but the present invention is not limited to this. Any frequency characteristic measuring unit 6 may be used as long as it measures harmonic distortion, and harmonic distortion other than second-order and third-order may be measured.

  Further, according to the above-described embodiment, the DSP unit 8 applies the equalizer of the banded filter, but the present invention is not limited to this. For example, a dip type equalizer may be applied.

  Further, according to the above-described embodiment, the equalizer of the banded filter for reducing the frequency band in which the chatter sound is generated by the DSP unit 8 is automatically applied, but the present invention is not limited to this. For example, a banded filter for removing the frequency band displayed by the vehicle assembly worker is displayed in front of the DSP unit 8 so that the frequency band in which the noise generated by the control unit 7 is generated is displayed on a display unit (not shown). Alternatively, it may be manually inserted between the DSP unit 8 and the amplifier unit 3.

  According to the embodiment described above, the following acoustic device 1, resonance sound attenuation method, and resonance sound reduction program can be obtained.

(Supplementary Note 1) A frequency characteristic measuring unit 6 that measures harmonic distortion of a current flowing through the connected speaker 2;
A control unit 7 for detecting a frequency band in which a resonance sound is generated from the frequency characteristics of the measured harmonic distortion;
A DSP unit 8 for attenuating a frequency band component detected by the control unit 7 in a reproduction signal reproduced by the speaker 2;
An acoustic device 1 comprising:

  (Additional remark 2) It is the resonance sound reduction method used for the audio equipment 1, Comprising: The measurement process which measures the harmonic distortion of the electric current which flows into the speaker 2 connected to the audio equipment 1, and the measured harmonic distortion A frequency detection step of detecting a frequency band in which resonance sound is generated from frequency characteristics; and an attenuation step of attenuating a frequency band component detected by the frequency detection step of the reproduction signal reproduced by the speaker 2 Resonant sound attenuation method characterized by the above.

(Supplementary Note 3) In the control unit 7 of the acoustic device 1 including the frequency characteristic measurement unit 6 that measures the harmonic distortion of the current flowing through the connected speaker 2,
The frequency characteristic measuring unit 6 is controlled to measure the harmonic distortion of the current flowing through the speaker 2,
The frequency band where the resonance sound is generated is detected from the frequency characteristics of the measured harmonic distortion.
A resonance noise reduction program characterized in that the DSP unit 8 of the audio device 1 attenuates a frequency band component detected in a reproduction signal reproduced by the speaker 2.

  According to Supplementary Notes 1, 2, and 3, since the frequency band component in which the resonance sound such as the noise is generated is attenuated, the noise is reduced without searching for the portion of the structure that is resonating with the vibration of the speaker 2. Can be easily reduced.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Sound apparatus 2 Speaker 4 Switching part (switching means)
6 Frequency characteristics measurement unit (measuring means)
7 Control unit (frequency band detection means)
8 DSP (Attenuation means)
R Resistance for measurement

Claims (10)

Measuring means for measuring harmonic distortion of the current flowing through the connected speaker;
A frequency band detecting means for detecting a frequency band in which a resonance sound is generated from the frequency characteristics of the measured harmonic distortion ;
Acoustic device characterized by comprising a. Attenuating means for attenuating the frequency band component detected by the frequency band detecting means of the reproduction signal reproduced by the speaker;
The acoustic device according to claim 1, further comprising: The acoustic device according to claim 2 , wherein the attenuation unit includes a band elimination filter that removes a frequency band component detected by the frequency band detection unit. Display means for displaying a frequency band component detected by the frequency band detection means in a reproduction signal reproduced by the speaker;
The acoustic device according to claim 1, further comprising: The resonance sound is generated by resonance of a structure to which the speaker is attached.
The acoustic device according to any one of claims 1 to 4, wherein the acoustic device is provided. The measuring means measures the admittance of the speaker;
The frequency band detection unit, according to claims 1 to 5 any one, characterized by detecting a frequency band in which the measured admittance and both the resonance noise from the frequency characteristics of the harmonic distortion occurs Sound equipment. Resistance for measurement,
Switching means for switching between a state in which the measurement resistor is connected in series to the speaker and a state in which the measurement resistor is not connected in series to the speaker;
Wherein the measuring means, when said switching means by a resistance for the measurement are connected in series to the speaker, one of claims 1-6, characterized in that performing the measurement on the basis of the current flowing through the resistor the measurement The acoustic device according to claim 1. Resonant sound detection method used in an acoustic device,
A measurement step of measuring harmonic distortion of a current flowing in a speaker connected to the acoustic device;
A frequency detection step of detecting a frequency band in which a resonance sound is generated from the frequency characteristics of the measured harmonic distortion;
A resonance sound detecting method comprising: In the computer of the acoustic device provided with the measuring means for measuring the harmonic distortion of the current flowing through the connected speaker,
By controlling the measurement means, to measure the harmonic distortion of the current flowing through the speaker,
Ru is detected the frequency band in which the resonance sound is generated from the measured frequency characteristics of the harmonic distortion was
Resonance sound detection program, wherein a call. A recording medium in which the resonance sound detection program according to claim 9 is recorded in a computer-readable manner.

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