A method for measuring the sound insulation of in-ear hearing protectors

Abstract

The present invention relates to a method for measuring the sound insulation of an in-ear hearing protector, comprising the following steps: after calibrating a test microphone and an in-ear microphone required for measurement, installing the test microphone and the in-ear microphone in the in-ear hearing protector to be tested and connecting the test microphone to a measurement system, and controlling the in-ear hearing protector to be inserted into the ear canal of a tester through the measurement system; in a test space, using a sound source to emit noise, and obtaining the sound pressure level I and the sound pressure level II outside and inside the in-ear hearing protector respectively through the measurement system based on the test microphone and the in-ear microphone, and obtaining the sound insulation of the in-ear hearing protector to be tested = sound pressure level II-sound pressure level I through spectrum analysis; wherein, calibrating the in-ear microphone specifically comprises: obtaining correction values ​​at a sound conduit, a joint and a perforated earplug in the measurement system respectively, and obtaining a calibration value after fitting.

Description

Technical Field

[0001] The invention relates to the technical field of sound insulation measurement, and in particular to a method for measuring the sound insulation of an in-ear hearing protector. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In-ear hearing protectors are protective equipment that can reduce hearing damage and are required to be worn by workers in some high-noise workplaces. Regarding the sound insulation effect of in-ear hearing protectors, the existing technology uses subjective feelings as the testing basis. Since different individuals (people) are used to participate in the test, there are individual differences between different subjects, and the sound insulation feelings obtained are different. Therefore, the sound insulation effect of the noise-proof in-ear hearing protectors can only be approximately evaluated, and the sound insulation amount or sound insulation effect of different in-ear hearing protectors cannot be accurately obtained.

[0004] In order to address the above-mentioned problems, in the prior art, two microphones are connected to the inside and outside of an in-ear hearing protector through a sound conduit. Under the same external sound source, data of the external environmental sound source and data in the ear canal of the tester are obtained respectively, and the difference between the two is the sound insulation of the in-ear hearing protector. Although this method solves the problem of being too subjective in the traditional method, due to the influence of its sound conduit, there is an error between the data obtained by the microphone for detecting the sound pressure and the actual data, and it is still difficult to reliably reflect the sound attenuation effect of the in-ear hearing protector. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a method for measuring the sound insulation of an in-ear hearing protector, and obtains correction values ​​at the sound conduit, the joint and the perforated earplug respectively, and obtains calibration values ​​for the test microphone and the in-ear microphone after formulating, so that the subsequent test process is closer to the real environment, thereby more accurately obtaining the sound insulation of the in-ear hearing protector to reflect its real sound attenuation effect.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides a method for measuring the sound insulation of an in-ear hearing protector, comprising:

[0008] After calibrating the test microphone and in-ear microphone required for measurement, install them into the in-ear hearing protector to be tested and connect them to the measurement system, and control the in-ear hearing protector to be inserted into the ear canal of the test person through the measurement system;

[0009] In the test space, a sound source is used to emit noise. The measurement system is based on the test microphone and the in-ear microphone to obtain the external and internal sound pressure levels I and II of the in-ear hearing protector respectively. The sound insulation of the in-ear hearing protector to be tested is obtained by spectrum analysis = sound pressure level II-sound pressure level I;

[0010] The in-ear microphone is calibrated by obtaining the correction values ​​of the sound conduit, the joint and the perforated earplug in the measurement system respectively, and the calibration value is obtained by fitting the following formula:

[0011]

[0012] L A ' is the sound pressure level correction value of the measurement system, L A is the sound pressure level measured by the measurement system, n is the number of octave bands, f is (k) is the center frequency of the octave band, k is the calibration coefficient of the sound conduit, d jt is the correction value of the joint, d es Correction value for perforated earplugs.

[0013] Obtain correction values ​​for the sound conduit, connector, and perforated earplug in the measurement system, including:

[0014] Under the same experimental conditions, the sound pressure levels L corresponding to the sound sources are obtained using sound sources of different frequencies. f(k)1 , and the sound pressure level L after the sound source is transmitted through the sound duct f(k)2 , calculate the calibration coefficient k=L in different frequency bands f(k)2 / L f(k)1 , select the corresponding calibration coefficient according to the actual acoustic conduit used in the measurement system;

[0015] The connector is connected between the sound guide tube and the microphone. Two microphones are used, one connected to the connector and the other not connected to the connector. Data of the two microphones are obtained based on the same sound source in the same test scene, and the difference between the two is taken as the correction value of the connector.

[0016] In the same test scenario, based on the same sound source, an artificial head simulator is used to wear a complete earplug and a perforated earplug respectively, and the difference between the sound data of the complete earplug and the perforated earplug is obtained as the correction value of the earplug.

[0017] The measurement system includes a sound conduit for connecting to an in-ear hearing protector, the sound conduit is sealed and connected to the open end of a sound insulation sleeve, an in-ear microphone is provided at one end of the sound conduit away from the sound insulation sleeve, a test microphone is provided inside the sound insulation sleeve, and the in-ear microphone and the test microphone are respectively connected to a spectrum analyzer.

[0018] The in-ear hearing protector to be tested is an earplug made of soft rubber or soft plastic. The earplug is punched and then inserted into the sound conduit to form a connection with the measurement system.

[0019] The sound source includes an AHAI2034 sound source, an AHAI2043 power amplifier and a signal generator. The signal generator controls the AHAI2043 power amplifier and the AHAI2034 sound source to emit various noises to provide a sound field.

[0020] The test microphone and the in-ear microphone are both AHAI14615E microphones.

[0021] When measuring the sound pressure level I in the ear canal using a measurement system, the tester performs several tests at different locations in the test space.

[0022] The test space is an anechoic chamber or a semi-anechoic chamber, the air pressure is 65kPa to 108kPa, the temperature of the test space is -10°C to 50°C, and the relative humidity of the test space is: 25% to 90%.

[0023] Compared with the prior art, one or more of the above technical solutions have the following beneficial effects:

[0024] 1. Obtain the correction values ​​of the sound conduit, joint and perforated earplug respectively, and obtain the calibration value for the microphone after formulating, so that the subsequent test process is closer to the real environment and the sound insulation of the in-ear hearing protector is obtained more accurately to reflect its real sound attenuation effect.

[0025] 2. It can accurately obtain the sound insulation of different styles of in-ear hearing protectors at different noise frequencies. The test takes into account the errors caused by the structural type of the sound conduit in the test device (system), the connection method of the joint, and the earplug type of the in-ear hearing protector. The sound conduit, joints and earplugs required for punching in the measurement system are calibrated in advance to get a closer look at the actual sound attenuation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0027] Figure 1 is a flow chart of measuring the sound insulation of an in-ear hearing protector provided by one or more embodiments of the present invention; DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0030] As described in the background technology, the prior art adopts a method of carrying two microphones on a sound conduit. Although this solves the problem of being too subjective in the traditional method, due to the influence of the sound conduit, there is an error between the data obtained by the microphone for detecting the sound pressure and the actual data, and it is still difficult to reliably reflect the sound attenuation effect of the in-ear hearing protector.

[0031] Therefore, the following embodiment provides a method for measuring the sound insulation of an in-ear hearing protector. Before the in-ear hearing protector is worn on the tester's ear, correction values ​​at the sound conduit, the joint and the perforated earplug are obtained respectively using an artificial head simulator, and calibration values ​​for the test microphone and the in-ear microphone are obtained after formulating, so that the subsequent test process is closer to the real environment, thereby more accurately obtaining the sound insulation of the in-ear hearing protector to reflect its real sound attenuation effect.

[0032] Embodiment 1:

[0033] A method for measuring the sound insulation of an in-ear hearing protector comprises the following steps:

[0034] Test microphone and ear microphone calibration;

[0035] The test microphone and the in-ear microphone are mounted on the in-ear hearing protector to be tested;

[0036] The test microphone is connected to the measurement system, and the tester wears an in-ear hearing protector equipped with an in-ear microphone;

[0037] In the test space, a noise is generated by using a sound source;

[0038] Using the test microphone and the in-ear microphone, obtain the sound pressure level I and sound pressure level II of the external and internal parts of the in-ear hearing protector respectively;

[0039] The sound pressure level I and the sound pressure level II are analyzed by spectrum analysis to obtain the sound insulation of the in-ear hearing protector to be tested = sound pressure level II - sound pressure level I.

[0040] Specific:

[0041] a. The in-ear hearing protector to be tested is installed on the measurement system, and the measurement system is worn on the test person's ear, and the measurement system and the in-ear hearing protector are inserted into the test person's ear canal; the measurement system includes: a sound guide tube, a sound insulation sleeve, an in-ear microphone, a test microphone and an ear-hanging bracket; the test microphone and the in-ear microphone use the same microphone, preferably a 1 / 4" test microphone; the specific structure of the measurement system is the "sound insulation measurement system" in the prior art CN113418686.

[0042] b. In the test space, the sound source includes the AHAI2034 sound source, the AHAI2043 power amplifier and the signal generator. The signal generator controls the AHAI2043 power amplifier and the AHAI2034 sound source to emit various noises to provide a sound field. The sound source emits noise, and the in-ear microphone in the measurement system is used to obtain the sound pressure level L in the ear canal. 内 , the sound pressure level L outside the ear canal is obtained through a test microphone located outside the ear 外 The test microphone can be AHAI14615E microphone. Place the sound source in six directions, up and down, left and right, and front and back, of the test person, and perform six measurements using the measurement system and the test microphone to obtain the average sound pressure level L 内 And the average sound pressure level L 外 .

[0043] In step b, this embodiment controls the sound source to emit pink noise.

[0044] In step b, the noise frequency of the pink noise emitted by the sound source of this embodiment is between 100 and 10000 Hz.

[0045] In step b, the distance between the sound source of this embodiment and the measurement system and the test microphone is 1 meter, and the measurement system and the microphone of this embodiment are placed side by side.

[0046] In step b, the reverberation time in the test space for each test signal does not exceed 1.6 seconds.

[0047] In step b, when measuring the sound pressure level I in the ear canal by the measurement system, the tester performs multiple tests at different positions in the test space.

[0048] In step b, the test space is an anechoic chamber or a semi-anechoic chamber.

[0049] In step b, the air pressure of the test space is 65 kPa to 108 kPa, the air temperature of the test space is -10°C to 50°C, and the relative humidity of the test space is 25% to 90%.

[0050] The in-ear hearing protectors that need to be tested are earplugs made of soft rubber or soft plastic.

[0051] The measurement system is calibrated before being inserted into the test person's ear canal together with the in-ear hearing protector.

[0052] c. The sound pressure level L in the ear canal obtained by the spectrum analyzer 内 and the sound pressure level outside the ear canal L 外 Perform spectrum analysis, sound pressure level L 外 -Sound pressure level L 内= volume isolation. The spectrum analyzer is an AHAI2001-1 multi-channel analyzer, which is connected to the AHAI14615E microphone and the measurement system via a BNC-SMB extension cable. The spectrum analyzer is electrically connected to an AWA8522 5V external power supply and is connected to a computer via a bidirectional USB cable.

[0053] The experimental site conditions are required to be consistent with those in the prior art CN113418686.

[0054] The test object in this embodiment is the 3M 1100 orange in-ear hearing protector. The data shown in Table 1 is the sound insulation data of the in-ear hearing protector with a sound guide tube tested using an artificial head simulator (a test instrument) and a 1 / 2" microphone.

[0055] Table 1 3M 1100 Orange In-Ear Hearing Protector Artificial Ear Sound Isolation Test Results

[0056]

[0057]

[0058] The data shown in Table 2 are for the control group, where the testers wore complete earplugs (test earplugs) connected to in-ear microphones and measured the hearing protectors without in-ear hearing protectors using a 1 / 2" microphone.

[0059] Table 2 Sound insulation test results

[0060]

[0061]

[0062] Table 3 uses 3M 1100 orange in-ear hearing protector as the test object. The average sound insulation obtained by wearing the measurement system together with the in-ear hearing protector to the ears of the test person is compared with the data obtained by the artificial head simulator in Table 1.

[0063] Table 3 Comparison of test results of in-ear hearing protector measurement system and artificial head simulator

[0064]

[0065]

[0066] Table 4 uses 3M 1100 orange in-ear hearing protector as the test object, and compares the control sound pressure level of the artificial ear without in-ear hearing protector, the sound pressure level received by the artificial head wearing a complete earplug, the sound pressure level received by the artificial head wearing a perforated earplug with a sound duct, and the difference in sound pressure level between the complete earplug and the perforated earplug with a sound duct.

[0067] Table 4 Comparative analysis data

[0068]

[0069] According to test data, placing a sound conduit in a perforated earplug will affect the test result of the earplug's sound insulation, and the actual insertion loss of the earplug needs to be corrected. Therefore, the measurement system of this embodiment is calibrated before being inserted into the test person's ear canal together with the in-ear hearing protector.

[0070] Taking the "sound insulation measurement system" in the prior art CN113418686 as an example, the sound conduit, the joint and the perforated earplug are corrected respectively, and the correction value is used as the calibration value of the final result.

[0071] 1. Calibration of the sound duct. The length of the sound duct will affect the detection of insertion loss. The longer the sound duct is, the greater its sound insulation is. The influence of the sound duct needs to be eliminated when calculating the final result. The sound insulation coefficient of sound ducts of different lengths is tested in the anechoic room using standard sound levels. Due to the different shapes of Christmas tree-shaped earplugs and bullet-shaped earplugs, the sound ducts used are of different lengths, and their sound insulation is different.

[0072] The specific process of obtaining the calibration coefficient is:

[0073] Step 1: In the reverberation room, emit sounds of different frequencies of 20Hz~100Hz, 125Hz~250Hz, 315Hz~500Hz, 630Hz~1000Hz, 1250Hz~2000Hz, 2500Hz~5000Hz, and 6300Hz~1000Hz, and use an artificial head simulator to detect the received sound pressure level L f(k)1 .

[0074] Step 2: In the reverberation room, emit sounds of different frequency bands, such as 20Hz~100Hz, 125Hz~250Hz, 315Hz~500Hz, 630Hz~1000Hz, 1250Hz~2000Hz, 2500Hz~5000Hz, and 6300Hz~1000Hz, and use an artificial head simulator to detect the sound pressure level L received through the sound conduit. f(k)2 .

[0075] Step 3: Calculate the calibration coefficient k = L at different frequency bands f(k)2 / L f(k)1 .

[0076] This embodiment takes the Christmas tree-shaped earplug and the bullet-shaped earplug as examples, and provides calibration coefficients of earplugs of different shapes as shown in Table 4:

[0077] Table 4 Calibration coefficients for bullet-shaped earplugs and Christmas tree-shaped earplugs

[0078]

[0079]

[0080] The influence of the connector. The connector is circular and is used to connect the sound guide tube and the microphone. It will affect the signal received by the microphone. The difference between the two microphones tested, one connected to the connector and the other not connected to the connector, is taken as the correction value d jt As shown in Table 5:

[0081] Table 5 Difference (corrected value) data of joints

[0082]

[0083] Perforated earplugs. The earplugs used in the measurement system need to be perforated, and the error of earplug insertion loss after perforation needs to be avoided. Using an artificial head and trunk simulator (a test instrument), in the same test scene, using the same sound source, using artificial ears to wear complete earplugs and perforated earplugs respectively, the difference between the two is used as the correction value. As shown in Table 6:

[0084] Table 6 Difference (corrected value) data of perforated earplugs

[0085]

[0086] After correcting the sound conduit, connector and perforated earplug respectively, the final calibration value is calculated using the following formula:

[0087]

[0088] L A ' is the corrected value of the sound pressure level received by the measurement system test, L A is the measured value of the sound pressure level received by the measurement system, n is the number of octave bands, f is (k) is the center frequency of the octave band, k is the calibration coefficient of the sound conduit, d jt is the correction value of the joint, d es Correction value for perforated earplugs.

[0089] In this embodiment, the sound pressure level received by the measurement system is the data obtained by the in-ear microphone, and its correction value L A 'It is also for the calibration of in-ear microphones. The calibration of test microphones is an existing technology. Taking foam bullet earplugs as an example, the calibration value data is shown in Table 7:

[0090] Table 7 Calibration value data

[0091]

[0092] The above method can accurately obtain the sound insulation of different styles of in-ear hearing protectors at different noise frequencies. The error caused by the test device (system) is taken into account in the test, and the sound conduit, joints and earplugs required for punching in the measurement system are calibrated in advance, so as to be closer to the real environment.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for measuring the sound insulation of an in-ear hearing protector, characterized in that: The following steps are involved: After calibrating the test microphone and in-ear microphone required for measurement, install them into the in-ear hearing protector to be tested and connect them to the measurement system, and control the in-ear hearing protector to be inserted into the ear canal of the test person through the measurement system; In the test space, a sound source is used to emit noise. The measurement system is based on the test microphone and the in-ear microphone to obtain the external and internal sound pressure levels I and II of the in-ear hearing protector respectively. The sound insulation of the in-ear hearing protector to be tested is obtained by spectrum analysis = sound pressure level II-sound pressure level I; The in-ear microphone is calibrated by obtaining the correction values ​​of the sound conduit, the joint and the perforated earplug in the measurement system respectively, and the calibration value is obtained by fitting the following formula: L A ' is the sound pressure level correction value of the measurement system, L A is the sound pressure level measured by the measurement system, n is the number of octave bands, f is (k) is the center frequency of the octave band, k is the calibration coefficient of the sound conduit, d jt is the correction value of the joint, d es Correction value for perforated earplugs; Obtain correction values ​​for the sound conduit, connector, and perforated earplug in the measurement system, including: Under the same experimental conditions, the sound pressure levels L corresponding to the sound sources are obtained using sound sources of different frequencies. f(k)1 , and the sound pressure level L after the sound source is transmitted through the sound duct f(k)2 , calculate the calibration coefficient k=L in different frequency bands f(k)2 / L f(k)1 , select the corresponding calibration coefficient according to the actual acoustic conduit used in the measurement system; Obtain correction values ​​for the sound conduit, connector and perforated earplug in the measurement system, including: The connector is connected between the sound guide tube and the microphone. Two microphones are used, one connected to the connector and the other not connected to the connector. Data of the two microphones are obtained based on the same sound source in the same test scene, and the difference between the two is taken as the correction value of the connector. Obtain correction values ​​for the sound conduit, connector and perforated earplug in the measurement system, including: In the same test scenario, based on the same sound source, an artificial head simulator is used to wear a complete earplug and a perforated earplug respectively, and the difference between the sound data of the complete earplug and the perforated earplug is obtained as the correction value of the earplug.

2. A method for measuring the sound insulation of an in-ear hearing protector as claimed in claim 1, characterized in that: The measurement system comprises a sound conduit for connecting to an in-ear hearing protector, the sound conduit is sealedly connected to the open end of a sound insulation sleeve, an in-ear microphone is arranged at one end of the sound conduit away from the sound insulation sleeve, a test microphone is arranged inside the sound insulation sleeve, and the in-ear microphone and the test microphone are respectively connected to a spectrum analyzer.

3. A method for measuring the sound insulation of an in-ear hearing protector as claimed in claim 1, characterized in that: The in-ear hearing protector to be tested is an earplug made of soft rubber or soft plastic. The earplug is punched and then inserted into the sound conduit to form a connection with the measurement system.

4. A method for measuring the sound insulation of an in-ear hearing protector as claimed in claim 1, characterized in that: The sound source includes an AHAI2034 sound source, an AHAI2043 power amplifier and a signal generator. The signal generator controls the AHAI2043 power amplifier and the AHAI2034 sound source to emit various noises to provide a sound field.

5. The method for measuring the sound insulation of an in-ear hearing protector according to claim 1, characterized in that: The test microphone and the in-ear microphone are both AHAI14615E microphones.

6. A method for measuring the sound insulation of an in-ear hearing protector as claimed in claim 1, characterized in that: When measuring the sound pressure level I in the ear canal using a measurement system, the tester performs several tests at different locations in the test space.

7. A method for measuring the sound insulation of an in-ear hearing protector as claimed in claim 1, characterized in that: The test space is an anechoic chamber or a semi-anechoic chamber, the air pressure is 65kPa to 108kPa, the temperature of the test space is -10°C to 50°C, and the relative humidity of the test space is: 25% to 90%.

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