A portable sound source for sound level meter testing

Abstract

This invention discloses a portable sound source for sound level meter testing, comprising: a semi-in-ear earphone as a sound-generating unit; a sound guide tube, with the semi-in-ear earphone disposed at the front end of the sound guide tube for conducting sound waves; a limiting component disposed at the rear end of the sound guide tube for limiting the insertion depth of the sound level meter microphone; a microphone index tube disposed at the rear end of the limiting component for fixing the sound level meter microphone; and an external shock-absorbing and sound-insulating tube covering the exterior of the above components. This portable sound source for sound level meter testing uses a semi-in-ear earphone and common tubing for assembly, making it easy to manufacture and promote. It is also small in size and lightweight, requiring no external power supply, and suitable for on-site sound level meter testing. This solution provides a single sound source covering the 20Hz-16kHz frequency band, eliminating the need for equipment switching, simplifying the operation process, and achieving integrated testing across the entire frequency band. Furthermore, it exhibits high sound field stability and good sound field uniformity.

Description

Technical Field

[0001] This invention relates to the field of acoustic testing technology, and specifically to a portable sound source for sound level meter testing. Background Technology

[0002] Currently, noise detection products mainly include sound level meters, noise statistical analyzers, sound exposure meters, and similar products. Sound detection is divided into two forms: acoustic signal detection and electrical signal detection. For acoustic signal detection, 500Hz is generally used as the dividing line. Below 500Hz, low-frequency coupling cavities are commonly used as the sound source, while above 500Hz, detection must be conducted in an anechoic chamber or anechoic enclosure. The sound source used for detection is generally a small speaker. However, existing technologies have the following problems: 1. Non-portability: The low-frequency coupling cavity is large in size (about 30cm×15cm×20cm) and weighs 4-5kg; the sound source used in the anechoic chamber also needs to be fixedly installed, which is inconvenient for on-site testing. 2. Low integration level: Currently, the sound source detection is divided into different types based on 500Hz, with different detection requirements. Below 500Hz, the sound source and the sound measurement product are in close contact. However, for frequencies above 500Hz, the sound source and the sound measurement product must be at least 1.1 meters apart, making it impossible to achieve integrated detection across the entire frequency band. 3. Poor sound source stability: Existing sound sources cannot guarantee sound pressure level stability within ±0.6 dBA in the 20 Hz–20 kHz range; 4. High energy consumption and dependence on external equipment: Most sound sources require supporting equipment and rely on 220V power supply, which limits their on-site application; 5. Poor sound field uniformity: Existing sound sources have strict requirements on the placement direction of the sound measurement products, making it difficult to guarantee the uniformity of the sound field. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, this invention provides a portable sound source for sound level meter testing, which solves the problems of large size, poor portability, poor sound source stability, and poor sound field uniformity in existing sound measurement products.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A portable sound source for sound level meter detection is provided, comprising: Semi-in-ear headphones, which serve as the sound-producing unit; The sound tube, located at the front end of the semi-in-ear headphone, is used to conduct sound waves. A limiting component, located at the rear end of the sound guide tube, is used to limit the insertion depth of the sound level meter microphone. A microphone index tube, located at the rear end of the limiting component, is used to fix the sound level meter microphone. An external vibration damping and sound insulation tube is used to cover the exterior of the aforementioned components.

[0005] Furthermore, semi-in-ear headphones are wired headphones, and their operating frequency is 20Hz-16kHz, with a sound pressure level of at least 120dBA in the range of 1kHz-8kHz.

[0006] Furthermore, the in-ear end face of semi-in-ear headphones is flat or curved, with a diameter between 16-19mm.

[0007] Furthermore, the sound guide tube is a silicone tube with an inner diameter of 15-16mm or a PTFE plastic tube with an inner diameter of 17-19mm, and its length is 6-11cm.

[0008] Furthermore, the limiting component is made of nylon and includes two integrally formed cylindrical tubes, both with an inner diameter of 13.0-13.1 mm. One cylindrical tube has a length and an outer diameter of 1.7 mm and 19 mm, respectively, while the other cylindrical tube has a length and an outer diameter of 4.7 mm and 16 mm, respectively.

[0009] Furthermore, the microphone index tube is made of nylon, with an inner diameter of 13.2-13.4 mm and a length of 1.5 cm.

[0010] Furthermore, the external vibration damping and sound insulation tube is a polyurethane through-tube structure, which is covered with an aluminum shell.

[0011] Furthermore, the repeatability of the sound pressure level of the portable sound source used for sound level meter testing is no greater than 0.8 dB in the range of 20 Hz to 16 kHz.

[0012] The beneficial effects of this invention are as follows: The portable sound source for sound level meter testing in this solution is assembled using a semi-in-ear headphone and common tubing, making it easy to manufacture and promote. It is also small in size and lightweight, requiring no external power supply, making it suitable for on-site sound level meter testing. This solution provides single-source coverage of the entire 10Hz-20kHz frequency band without the need for equipment switching, simplifying the operation process and enabling integrated testing across the entire frequency band. Furthermore, it boasts high sound field stability and good sound field uniformity, making it suitable for 1 / 2-inch microphones, which account for over 95% of the market, facilitating compatibility with various sound level meters, noise statistical analyzers, and other equipment. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The above and other objects, features, and advantages of the present invention will become clearer through the accompanying drawings. The same reference numerals indicate the same parts in all the drawings. The drawings are not intentionally drawn to scale to actual dimensions; the focus is on illustrating the main points of the invention.

[0014] Figure 1 This is a schematic diagram of a portable sound source used for sound level meter testing.

[0015] Figure 2 Exploded view of a portable sound source used for sound level meter testing.

[0016] Figure 3 The first data plot for repeatability test data.

[0017] Figure 4 The second data plot is for repeatability test data.

[0018] Figure 5 This is the third data plot for repeatability test data.

[0019] Figure 6 This is a graph showing the test data from a Class I sound level meter.

[0020] Figure 7 This is a graph showing the test data from a secondary sound level meter.

[0021] Figure 8 This is a graph showing the test data from a Level 1 noise statistical analyzer.

[0022] Figure 9 This is a graph showing the test data from a Level 2 noise statistical analyzer.

[0023] Among them, 1. semi-in-ear headphones, 2. sound guide tube, 3. limiting component, 4. microphone index tube, and 5. external shock absorption and sound insulation tube. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0028] like Figure 1 and Figure 2 As shown, the portable sound source for sound level meter testing in this solution includes: a semi-in-ear earphone 1, which serves as the sound-generating unit; a sound guide tube 2, with the semi-in-ear earphone 1 positioned at the front end of the sound guide tube 2, used to conduct sound waves; a limiting component 3, positioned at the rear end of the sound guide tube 2, used to limit the insertion depth of the sound level meter microphone; a microphone index tube 4, positioned at the rear end of the limiting component 3, used to fix the sound level meter microphone; and an external shock-absorbing and sound-insulating tube 5, which covers the exterior of the above components and can be fixedly connected by adhesive bonding.

[0029] In practical implementation, the overall design of this scheme is based on the size of the sound level meter microphone: 1 / 2 inch (12.7mm) is the main size, which accounts for more than 95% of the current total; the diameter of its outer shell end face is between 13.1mm and 13.2mm; when in use, the sound level meter microphone is inserted into the microphone index tube 4 for testing, to a depth of about 1.5cm.

[0030] Because most in-ear headphones have an irregular, multi-faceted shape, their sound-emitting position causes more severe unevenness in the transmission of sound through the tube, so they are not selected. The semi-in-ear headphones 1 have a flat or curved in-ear end face with a diameter between 16-19mm, making them small and easy to carry. The semi-in-ear headphones 1 are wired to avoid the sound transmission distortion caused by Bluetooth headphones. The operating frequency of the semi-in-ear headphones 1 is 20Hz-16kHz, and the sound pressure level is at least 120dBA in the range of 1kHz-8kHz to facilitate testing with a Class I sound level meter.

[0031] As a key component for transmitting sound waves from one end to the other, the sound guide tube 2 is crucial because sound waves do not propagate at a single frequency under non-vacuum conditions, but rather at all frequencies from 20Hz to 16kHz. The sound guide tube 2 can clearly distinguish the sound wave at a certain detection frequency from other frequencies, generally by a sound pressure level 20dB higher. Since sound waves attenuate with increasing distance and the sound pressure level decreases, the length of the sound guide tube 2 cannot be too long. Therefore, in this design, the sound guide tube 2 is preferably a silicone tube with an inner diameter of 15-16mm or a PTFE plastic tube with an inner diameter of 17-19mm, and its length is 6-11cm.

[0032] The limiting component 3 is used to limit the insertion depth of the sound level meter microphone. Since the length of the sound guide tube 2 is fixed, its sound pressure level at different frequencies is also fixed. If the insertion depth is too deep or too shallow, the sound pressure level value will change, thus affecting its accuracy. The limiting component 3 in this solution is made of nylon and includes two integrally formed cylindrical tubes. The inner diameter of the two cylindrical tubes is 13.0-13.1mm. The length and outer diameter of one cylindrical tube are 1.7mm and 19mm, respectively, and the length and outer diameter of the other cylindrical tube are 4.7mm and 16mm, respectively.

[0033] The microphone index tube 4 in this design is made of nylon with an inner diameter of 13.2-13.4mm and a length of 1.5cm. The outer shock-absorbing and sound-insulating tube 5 is a polyurethane through-tube structure with an aluminum shell covering it. This is to prevent noise from the environment in which the portable sound source is located from seeping into the sound source and interfering with its standard sound source. It also prevents the portable sound source from being damaged by external factors such as drops, bumps, and collisions due to improper placement.

[0034] The portable sound source used for sound level measurement in this scheme has a sound pressure level repeatability of no more than 0.4 dB in the range of 20 Hz to 16 kHz, and a sound pressure level repeatability of no more than 0.7 dB at 20 kHz.

[0035] The portable sound source used for sound level meter testing in this scheme will be tested below: Test conditions: Frequency weighting from 20Hz to 20kHz; 3-month test using the same Level 1 noise statistical analyzer; the frequency generator and attenuator used in the test were the same combination of devices, only the sound source was new. Tests were conducted at 20Hz-20kHz (test points: 20Hz, 32Hz, 63Hz, 125Hz, 250Hz, 500Hz, 1000Hz, 2000Hz, 4000Hz, 8000Hz, 16000Hz, 20000Hz). At each test point, the Z-weighting of the Level 1 statistical analyzer was set to 100dB or 80dB. The attenuation value at each test point was recorded three times a day for 3 months, and the repeatability of the data was calculated. (For frequencies not exceeding 1kHz, the test was conducted at 1kHz and 100dBA; for frequencies exceeding 1kHz, the test was conducted at 1kHz and 80dBA).

[0036] Repeatability test data such as Figures 3 to 5 As shown; the test data of the primary sound level meter and the secondary sound level meter are as follows: Figure 6 and Figure 7 As shown; the test data from the Level 1 and Level 2 noise statistical analyzers are as follows: Figure 8 and Figure 9 As shown.

[0037] In summary, this solution provides single-source coverage across the entire 10Hz-20kHz frequency band without requiring equipment switching, simplifying the operation process and enabling integrated detection across the entire frequency band. Furthermore, it boasts high sound field stability and uniformity, making it suitable for 1 / 2-inch microphones, which account for over 95% of the market, facilitating compatibility with various sound level meters, noise statistical analyzers, and other equipment. Additionally, this solution utilizes a semi-in-ear headphone and commonly used tubing for assembly, simplifying manufacturing and promotion. Moreover, its small size, light weight, and lack of external power supply make it suitable for on-site sound level meter testing.

[0038] Although the specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent; various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. A portable sound source for sound level meter detection, characterized in that, include: Semi-in-ear headphones, which serve as the sound-producing unit; The sound guide tube, wherein the semi-in-ear earphone is disposed at the front end of the sound guide tube, is used to conduct sound waves; A limiting component, located at the rear end of the sound guide tube, is used to limit the insertion depth of the sound level meter microphone. A microphone index tube, located at the rear end of the limiting component, is used to fix the sound level meter microphone. An external vibration damping and sound insulation tube is used to cover the exterior of the aforementioned components.

2. The portable sound source for sound level meter detection according to claim 1, characterized in that, The semi-in-ear headphones are wired headphones, and the operating frequency of the semi-in-ear headphones is 20Hz-16kHz, and the sound pressure level reaches at least 120dBA in the range of 1kHz-8kHz.

3. The portable sound source for sound level meter detection according to claim 2, characterized in that, The in-ear end face of the semi-in-ear earphone is flat or curved, with a diameter between 16-19mm.

4. The portable sound source for sound level meter detection according to claim 1, characterized in that, The sound guide tube is a silicone tube with an inner diameter of 15-16mm or a PTFE plastic tube with an inner diameter of 17-19mm, and its length is 6-11cm.

5. The portable sound source for sound level meter detection according to claim 1, characterized in that, The limiting component is made of nylon and includes two integrally formed cylindrical tubes. The inner diameter of the two cylindrical tubes is 13.0-13.1 mm. The length and outer diameter of one cylindrical tube are 1.7 mm and 19 mm, respectively, and the length and outer diameter of the other cylindrical tube are 4.7 mm and 16 mm, respectively.

6. The portable sound source for sound level meter detection according to claim 1, characterized in that, The microphone index tube is made of nylon, with an inner diameter of 13.2-13.4 mm and a length of 1.5 cm.

7. The portable sound source for sound level meter detection according to claim 1, characterized in that, The external shock-absorbing and sound-insulating tube is a polyurethane through-tube structure, which is covered with an aluminum shell.

8. The portable sound source for sound level meter detection according to claim 1, characterized in that, The portable sound source used for sound level measurement has a sound pressure level repeatability of no more than 0.8 dB in the range of 20 Hz to 16 kHz.

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