Angle-adjustable high-precision spherical sound field generating and positioning system

Abstract

The invention relates to the technical field of acoustic measurement, in particular to an angle-adjustable high-precision spherical sound field generation and positioning system, which comprises a sound source conduit, a sound source detection module, a sound source detection module, a sound source detection module and a sound source detection module, and is characterized in that the sound source conduit is sequentially provided with a contraction section and a straight filtering section from a first end to a second end; the inner diameter of the contraction section is gradually reduced in the direction towards the straight filtering section; an inner hole of the straight filtering section is of an equal-diameter structure; the diaphragm type loudspeaker is mounted at the first end of the sound source conduit; a sound production part of the diaphragm type loudspeaker faces the sound source conduit; the other end of the connecting piece is fixedly connected with the outer side, close to the first end, of the sound source conduit; the reference microphone is fixedly arranged on the sound source conduit; the far-field microphone is used for collecting sound pressure level data at a set position; and judging whether the sound field is consistent or not. According to the invention, the incident angle of the sound source relative to the measuring point can be rapidly and conveniently adjusted, and the experiment can be carried out at a specific radius and angle.

Description

Technical Field

[0001] The present disclosure relates to the technical field of acoustic measurement, and particularly to a high-precision spherical sound field generation and positioning system with adjustable angle. Background Art

[0002] A monopole point source is an idealized sound source model in acoustics, usually used to simplify the analysis of sound wave propagation. In this model, the sound source can be regarded as a point-like and uniformly sounding source, which can radiate sound waves with equal intensity in all directions to form a spherical sound field. The monopole point source is widely used in the field of acoustic measurement. Under free-field conditions, it can be used as a reference source for the optimization design of sound source identification and positioning, the analysis of the influence of microphone brackets on scattering, etc. Under semi-anechoic conditions, it can be used for the research of ground acoustic measurement correction factors, etc. It can also be used for noise transfer function and acoustic transfer function analysis, precise acoustic excitation tests such as sound insulation and sound absorption tests. To ensure the high-quality progress of the above research, high requirements are often placed on the accuracy of the generated spherical wave sound field. During the experimental measurement process, the consistency of the sound source also needs to be ensured for the situation of changing the experimental settings in the test sound field. For the method of generating a spherical wave sound field, the existing technical solution is to directly play and generate a sound field using a single small speaker that can be purchased on the market, such as a Bluetooth speaker of some companies. Further, a certain company connects a high-power speaker to a conical coupler so that the sound wave radiates from a round hole and then emits sound evenly in all directions. A certain company also produces a medium-high frequency volume sound source (VSS210A) for simulating an ideal omnidirectional point sound source.

[0003] In the prior art, it is difficult to ensure that the sound field directly generated by a single small speaker is a high-precision spherical wave sound field, and the quality of the sound field has not been tested. To obtain a higher-quality sound field, it is often necessary that when the scale of the sound source is much smaller than the wavelength of the sound wave it emits, the phases of the vibrations of its various parts are approximately the same, so that it can be regarded as a point sound source. The frequency range of the spherical wave sound source generator has been determined (50Hz - 6300Hz), and it is impossible to define the upper limit of the sound source frequency for specific experimental situations by itself; the accuracy of the medium-high frequency volume sound source (VSS210A) as a monopole source is relatively low, and the sound pressure level deviation per 30° can reach ±5dB.

[0004] For a piston-type speaker, when ka is less than 1, the radiation is almost uniform in all directions. At this time, the directivity pattern can be regarded as a circle. As the ka value increases, the directivity becomes sharper, and there will be obvious differences in the sound fields directly in front of and on both sides of the sound source.

[0005] For the solution of using a reference microphone placed in the sound field to test the consistency of sound sources, there are the following disadvantages: It is necessary to ensure that the relative positions of the reference microphone and the sound source are always consistent. If the sound source moves, the reference microphone should also move accordingly. It is difficult to ensure that their relative positions are strictly consistent during this process. If the external environment changes during the experiment, for example, from an anechoic environment to a semi-anechoic environment, the comparison of the reference microphone data under the two conditions is meaningless. At this time, it is impossible to explain the consistency of the sound sources in these two environments based on the data obtained by the reference microphone, and this solution has environmental dependence.

[0006] For the solution of fixing the spherical wave generating device at a specific angular position on the arc segment, there are the following disadvantages: After processing the arc segment with a specific radius, the test radius is determined. If different test radii are required for subsequent experiments, new arc segments need to be processed, and the economy is poor. Summary of the Invention

[0007] In view of the above problems, the present disclosure is proposed. The present disclosure provides an adjustable-angle high-precision spherical sound field generating and positioning system.

[0008] According to one aspect of the present disclosure, there is provided an adjustable-angle high-precision spherical sound field generating and positioning system, which includes:

[0009] A sound source conduit, along the direction from the first end to the second end, a contraction section and a straight filtering section are sequentially provided; along the direction towards the straight filtering section, the inner diameter of the contraction section gradually becomes smaller; the inner hole of the straight filtering section is a constant-diameter structure, and the inner hole diameter of the straight filtering section is equal to the inner diameter of the end of the contraction section close to the straight filtering section;

[0010] A diaphragm loudspeaker, the diaphragm loudspeaker is installed at the first end of the sound source conduit; and the sound-emitting part of the diaphragm loudspeaker faces the sound source conduit;

[0011] A connecting member, one end of the connecting member is rotatably connected, and the other end is fixedly connected to the outside of the sound source conduit close to the first end;

[0012] A reference microphone, the reference microphone is fixedly arranged on the sound source conduit and is used for collecting sound pressure level data;

[0013] A far-field microphone, the far-field microphone is used for collecting sound pressure level data at a set position;

[0014] A data acquisition and processing unit, electrically connected to the reference microphone and the far-field microphone, the data acquisition and processing unit is used for collecting the detection results of the reference microphone and the far-field microphone and judging whether the sound field is consistent.

[0015] The adjustable-angle high-precision spherical sound field generation and positioning system as described above, wherein, optionally, it further includes a crossbeam, and the crossbeam is horizontally arranged; one end of the connecting member away from the sound source conduit is sleeved on the crossbeam and can rotate around the crossbeam;

[0016] Based on the measurement point, the horizontal distance between the center line of the crossbeam and the measurement point is:

[0017]

[0018] The vertical distance between the center line of the crossbeam and the measurement point is:

[0019]

[0020] Wherein, r2 is the distance from the measurement point to the center line of the crossbeam; θ1 is the angle between the center line of the sound source conduit and the horizontal plane; r is the given distance from the measurement point to the second end of the sound source conduit; a is the distance from the second end of the sound source conduit along its center line to the vertical plane passing through the center line of the crossbeam; b is the distance between the center line of the crossbeam and the center line of the sound source conduit.

[0021] The adjustable-angle high-precision spherical sound field generation and positioning system as described above, wherein, optionally, the number of the reference microphones is at least 3, the reference microphones are arranged along the length direction of the sound source conduit, and the distances between adjacent reference microphones are different.

[0022] The adjustable-angle high-precision spherical sound field generation and positioning system as described above, wherein, optionally, the data acquisition and processing unit is used to obtain the measurement results of the reference microphones and the far-field microphones, and take the maximum value of the sound pressure level data in the measurement results of the reference microphones As the consistency test value;

[0023] Before the experiment, mark the distance of the measurement point of the far-field microphone relative to the second end of the sound source conduit and the angle relative to the center line of the sound source conduit. The sound pressure level data of this microphone measurement point at a specific frequency in different experiments is Establish a correction function for the sound pressure level data measured by the reference microphones and the far-field microphones at different specific frequencies:

[0024]

[0025] Conduct multiple measurements at different frequencies and obtain the calibration curve of the far-field microphone at the corresponding measurement point;

[0026] During the experiment, callback the far-field microphone to the position marked before the experiment, and judge whether the curve obtained by sweeping the frequency coincides with the calibration curve. If it coincides, the sound field is consistent.

[0027] The adjustable-angle high-precision spherical sound field generation and positioning system as described above, wherein, optionally, it further includes a locking member, and the locking member is installed on the connecting member for locking the cross beam and the connecting member.

[0028] The adjustable-angle high-precision spherical sound field generation and positioning system as described above, wherein, optionally, the locking member is a bolt, the bolt is in threaded connection with the locking member, and one end of the bolt can abut against the surface of the cross beam.

[0029] The adjustable-angle high-precision spherical sound field generation and positioning system as described above, wherein, optionally, the outer diameter of the straight filtering section gradually becomes smaller in the direction away from the contraction section.

[0030] The adjustable-angle high-precision spherical sound field generation and positioning system as described above, wherein, optionally, the inner diameter calculation formula of the straight filtering section is:

[0031]

[0032] wherein, f c is the cut-off frequency of the conduit filtering section, k mn is the radial wave number under the rigid wall condition, c0 is the sound speed, and a is the radius of the filtering section.

[0033] The adjustable-angle high-precision spherical sound field generation and positioning system as described above, wherein, optionally, the length of the sound source conduit is 0.5 to 1.5 meters.

[0034] As will be described in detail below, according to an embodiment of the present disclosure, an adjustable-angle high-precision spherical sound field generation and positioning system. Since the diameter at the outlet of the diaphragm loudspeaker often does not match the calculated diameter of the filtering section conduit, the function of the contraction section is to gradually and smoothly transition the diameter at the inlet of the sound source conduit to the diameter of the filtering section. At the same time, the cross-sectional area contraction can better concentrate the sound energy to fully exert the performance of the loudspeaker. The higher-order modes that may be generated in the conduit during the process of gradually decreasing the cross-sectional area of the conduit will be attenuated in the subsequent filtering section. At this time, only pure plane waves are in the conduit, and finally they are radiated out from the circular hole at the end of the conduit and emit sound evenly in all directions. The present invention can generate a high-precision spherical sound field with different upper frequency limits according to experimental requirements, and ensure the sound source intensity and sound field consistency without being affected by the external environment under different experimental settings. It can quickly and conveniently adjust the incident angle of the sound source relative to the measurement point to ensure that the experiment is carried out at a specific radius and angle.

[0035] It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the claimed technology. Brief Description of the Drawings

[0036] The above and other objects, features, and advantages of the present disclosure will become more apparent by describing the embodiments of the present disclosure in more detail with reference to the accompanying drawings. The drawings are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation to the present disclosure. In the drawings, the same reference numerals generally represent the same components or steps.

[0037] Figure 1 is a schematic structural diagram of an adjustable-angle high-precision spherical sound field generation and positioning system proposed by the present invention;

[0038] Figure 2 is a schematic installation structure diagram of a sound source conduit proposed by the present invention;

[0039] Figure 3 is a schematic calculation diagram of a measurement point proposed by the present invention;

[0040] Figure 4 is a schematic diagram of a calibration curve proposed by the present invention.

[0041] Description of the Reference Numerals:

[0042] 1 - Sound source conduit, 2 - Diaphragm loudspeaker, 3 - Connector, 4 - Reference microphone, 5 - Far-field microphone, 6 - Data acquisition and processing unit, 7 - Cross beam;

[0043] 11 - Contraction section, 12 - Straight filtering section. Detailed Embodiments

[0044] In order to make the objectives, technical solutions, and advantages of the present disclosure more apparent, the exemplary embodiments according to the present disclosure will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure. It should be understood that the present disclosure is not limited by the exemplary embodiments described herein.

[0045] In response to the problems raised in the background art, the present invention proposes the following solutions.

[0046] Please refer to Figures 1 to 3, the present invention discloses a system for generating and positioning a high-precision spherical sound field with adjustable angle, which includes a sound source duct 1, a diaphragm loudspeaker 2, a connecting member 3, a reference microphone 4, a far-field microphone 5, and a data acquisition and processing unit 6. Specifically, the sound source duct 1 is successively provided with a contraction section 11 and a straight filtering section 12 along the direction from the first end to the second end; along the direction towards the straight filtering section 12, the inner diameter of the contraction section 11 gradually decreases; the inner hole of the straight filtering section 12 has a constant diameter structure, and the inner hole diameter of the straight filtering section 12 is equal to the inner diameter of the end of the contraction section 11 close to the straight filtering section 12. The inner hole diameter of the straight filtering section 12 is smaller than the diameter of the sound-emitting part of the diaphragm loudspeaker 2.

[0047] The diaphragm loudspeaker 2 is installed at the first end of the sound source duct 1; and the sound-emitting part of the diaphragm loudspeaker 2 faces the sound source duct 1. One end of the connecting member 3 is rotatably connected, and the other end is fixedly connected to the outer side of the sound source duct 1 close to the first end. Setting the connecting member 3 at a position close to the first end can ensure that the connecting member 3 is as far away from the second end as possible, which can reduce the influence of the connecting member 3 on the sound source outlet of the sound source duct 1, so that the sound wave emitted from the second end of the sound source duct 1 can form a spherical sound field.

[0048] In specific implementation, according to the theory of cylindrical tube acoustic waveguide management, a straight filtering section 12 that filters out high-order modes and only propagates plane waves below the cut-off frequency can be designed, and the diameter of the straight filtering section 12 is obtained by calculating the upper limit of the frequency required by actual experiments. Specifically, the inner diameter calculation formula of the straight filtering section 12 is:

[0049]

[0050] where f c is the cut-off frequency of the duct filtering section, k mn is the radial wave number under the rigid wall condition, c0 is the speed of sound, and a is the radius of the filtering section.

[0051] Since the diameter at the outlet of the diaphragm loudspeaker 2 is often inconsistent with the inner diameter of the calculated straight filtering section 12, the function of the contraction section 11 is to gradually and smoothly transition the diameter at the inlet of the sound source duct 1 to the inner diameter of the straight filtering section 12. At the same time, the cross-sectional area contraction can better concentrate the sound energy to fully exert the performance of the diaphragm loudspeaker 2. During the process of the gradual reduction of the cross-sectional area of the sound source duct 1, the possible high-order modes generated in the tube will decay in the subsequent filtering section. At this time, only pure plane waves exist in the sound source duct 1, and finally they are radiated from the circular hole at the second end of the sound source duct 1 and emit sound evenly in all directions.

[0052] In specific implementation, to ensure the uniformity of the sound field during the test, the reference microphone 4 is fixedly arranged on the sound source duct 1 for collecting sound pressure level data; the far-field microphone 5 is used for collecting sound pressure level data at a set position; electrically connected to the reference microphone 4 and the far-field microphone 5, the data acquisition and processing unit 6 is used for collecting the detection results of the reference microphone 4 and the far-field microphone 5 and judging whether the sound field is uniform.

[0053] The number of the reference microphones 4 is at least 3, the reference microphones 4 are arranged along the length direction of the sound source duct 1, and the distances between adjacent reference microphones 4 are different. Arranging 4 reference microphones 4 on the wall surface of the sound source duct 1 can detect the sound source intensity in different experiments without being affected by the environment to ensure the sound source consistency. Further, arranging the far-field microphone 5 outside the sound source duct 1 can detect the sound source intensity in different experiments without being affected by the environment to ensure the sound source consistency. Further, arranging microphone measurement points outside the sound source duct can be used for spherical sound field positioning and ensure the sound field consistency.

[0054] Specifically, the data acquisition and processing unit 6 is used for obtaining the measurement results of the reference microphone 4 and the far-field microphone 5, and taking the maximum value of the sound pressure level data in the measurement results of the reference microphone 4 as the consistency test value.

[0055] Before the test, mark the distance of the measurement point of the far-field microphone 5 relative to the second end of the sound source duct 1 and the angle relative to the center line of the sound source duct 1. The sound pressure level data of this microphone measurement point at a specific frequency in different experiments is Establish a correction function for the sound pressure level data measured by the reference microphone 4 and the far-field microphone 5 at different specific frequencies:

[0056]

[0057] Perform multiple measurements at different frequencies, and obtain the calibration curve of the far-field microphone 5 at the corresponding measurement point. The calibration curve is a curve of ΔSPL varying with frequency. The abscissa of this calibration curve is the frequency, and the ordinate is ΔSPL calculated in the above formula. Before the test, we will generate sound source signals of different frequencies, such as setting a 1 / 3 octave sweep range (315 Hz, 400 Hz, 500 Hz, 630 Hz, 800 Hz, 1000 Hz, 1250 Hz, 1600 Hz, 2000 Hz, 2500 Hz, 3150 Hz, etc.). Perform at least 3 data acquisitions at the same frequency, and average the obtained sound pressure level data to obtain the corresponding ΔSPL value at a single frequency. At this time, a schematic diagram can be obtained as Figure 4As shown, interpolation is performed on the data points calibrated before the test and then connected into a smooth curve. Then, the data points measured in a certain test are compared with the curve obtained by interpolation. If the difference between the calibrated data points is within ±0.5 dB, it can be determined that the sound field is consistent with the sound field calibrated before the test, which is beneficial to improving the accuracy of the test.

[0058] During the test, the far-field microphone 5 is adjusted back to the position marked before the test, and it is judged whether the curve obtained by sweeping the frequency coincides with the calibrated curve. If they coincide, the sound fields are consistent. By judging the consistency of the sound fields, it is beneficial to ensure the consistency of the sound sources and is beneficial to improving the accuracy of the test.

[0059] In specific implementation, please refer to Figure 3 In order to facilitate the arrangement of the sound source duct 1 and to form different incident angles conveniently and reduce the cost of controlling the incident angle, in the present invention, a cross beam 7 is further included. The cross beam 7 is horizontally arranged. One end of the connecting member 3 away from the sound source duct 1 is sleeved on the cross beam 7 and can rotate around the cross beam 7.

[0060] Taking the measuring point as a reference, the horizontal distance between the center line of the cross beam 7 and the measuring point is:

[0061]

[0062] The vertical distance between the center line of the cross beam 7 and the measuring point is:

[0063]

[0064] Among them, r2 is the distance from the measuring point to the center line of the cross beam 7, that is, the length of the line segment AC; θ1 is the angle between the center line of the sound source duct 1 and the horizontal plane, that is, ∠EAB; r is the given distance from the measuring point to the second end of the sound source duct 1; a is the distance from the second end of the sound source duct 1 along its center line to the vertical plane passing through the center line of the cross beam 7; b is the distance between the center line of the cross beam 7 and the center line of the sound source duct 1.

[0065] Specifically, the connecting member 3 can rotate 360 degrees around the cross beam 7 to facilitate adjusting the incident angle according to actual needs.

[0066] In specific implementation, to facilitate fixing the sound source duct 1 at a desired position, the present invention further includes a locking member. The locking member is installed on the connecting member 3 and is used to lock the cross beam 7 and the connecting member 3. Specifically, when the angle of the sound source duct 1 needs to be adjusted, the locking member is loosened. After adjusting to the desired angle, the locking member is used for locking so that the sound source duct 1 is fixed at the desired position. In some implementation manners, the locking member is a bolt, and the bolt is in threaded connection with the locking member. One end of the bolt can abut against the surface of the cross beam 7. That is, by rotating the bolt forward or backward, the loosening or locking of the connecting member 3 can be achieved.

[0067] In specific implementation, the outer diameter of the straight filtering section 12 gradually decreases in a direction away from the contraction section 11. In this way, the influence on the second end of the sound source duct 1 can be reduced to ensure the accuracy of the spherical sound field. In specific implementation, the length of the sound source duct 1 is 0.5 to 1.5 meters. It is found through simulation that the length of the sound source duct 1 is preferably in the range of 0.5 to 1.5 meters, and preferably 1 meter.

[0068] As described above, with reference to the drawings, an adjustable-angle high-precision spherical sound field generation and positioning system according to an embodiment of the present disclosure is described. Since the diameter at the outlet of the diaphragm loudspeaker often does not match the calculated diameter of the filtering section duct, the function of the contraction section is to gradually and smoothly transition the diameter at the inlet of the sound source duct to the diameter of the filtering section. At the same time, the cross-sectional area contraction can better concentrate the sound energy to fully exert the performance of the loudspeaker. The higher-order modes that may be generated in the duct during the gradual reduction of the duct cross-sectional area will be attenuated in the subsequent filtering section. At this time, only pure plane waves are in the duct, and finally they are radiated from the circular hole at the end of the duct and emit sound evenly in all directions. The present invention can generate high-precision spherical sound fields with different upper frequency limits according to experimental requirements, and ensure the sound source intensity and sound field consistency without being affected by the external environment under different experimental settings. The incident angle of the sound source relative to the measurement point can be adjusted quickly and relatively conveniently to ensure that the experiment is carried out at a specific radius and angle.

[0069] For a piston - type sound source, when the ka number is small (ka < 1), the radiation is almost uniform in all directions. It can be approximately regarded as a point source, generating a spherically symmetric sound field with uniform spherical waves. The directivity pattern can be regarded as a circle. As the ka number increases, the sound field generated by the piston - type loudspeaker will gradually exhibit directivity characteristics. The sound pressure level directly in front of the sound source will be significantly higher than that on both sides in front of the sound source, and this directivity will become sharper as the ka number increases. Therefore, designing the sound source with an adjustable angle can ensure that the sound source is always directly facing the microphone under different experimental conditions, avoiding the microphone being on the front - side of the sound source and resulting in distortion of the received sound source information in the high - frequency part. Among them, ka is the Helmholtz number. Here, k = Ω / c, where Ω is the angular frequency, c is the speed of sound, and a is the geometric dimension. For the problem of sound propagation in a circular tube, Ω = 2π·f, where f is the frequency of the sound source. The higher the frequency of the sound source, the larger the ka number.

[0070] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present disclosure are only examples and not limitations. It cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present disclosure. Additionally, the specific details disclosed above are only for illustrative and facilitating understanding purposes, rather than limitations. These details do not limit the present disclosure to necessarily implementing with the above - specific details.

[0071] The block diagrams of the devices, apparatuses, equipment, and systems involved in the present disclosure are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open - ended terms, meaning "including but not limited to", and can be used interchangeably with each other. The words "or" and "and" used here refer to "and / or", and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with each other.

[0072] In addition, as used herein, the "or" used in the listing of items starting with "at least one" indicates a disjunctive listing. For example, the listing of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the term "exemplary" does not mean that the described examples are preferred or better than other examples.

[0073] It should also be noted that in the systems and methods of the present disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present disclosure.

[0074] Various changes, substitutions, and alterations to the technology described herein may be made without departing from the teachings defined by the appended claims. Additionally, the scope of the claims of this disclosure is not limited to the specific aspects of the processes, machines, manufactures, compositions of events, means, methods, and acts described above. Current or later-developed processes, machines, manufactures, compositions of events, means, methods, or acts that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein may be utilized. Accordingly, the appended claims include such processes, machines, manufactures, compositions of events, means, methods, or acts within their scope.

[0075] The foregoing description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0076] The foregoing description has been presented for purposes of illustration and description. Additionally, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although several example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and subcombinations thereof.

Claims

1. A high-precision spherical sound field generation and positioning system with adjustable angle, characterized in that: include: A sound source conduit (1), wherein the sound source conduit (1) is provided with a contraction section (11) and a straight filter section (12) in sequence along a direction from a first end to a second end; the inner diameter of the contraction section (11) gradually decreases in a direction toward the straight filter section (12); the inner hole of the straight filter section (12) is a constant diameter structure, and the inner hole diameter of the straight filter section (12) is equal to the inner diameter of one end of the contraction section (11) close to the straight filter section (12); A diaphragm loudspeaker (2), the diaphragm loudspeaker (2) being mounted on a first end of the sound source conduit (1); and a sound-generating portion of the diaphragm loudspeaker (2) is facing the sound source conduit (1); A connecting member (3), one end of which is rotatably connected, and the other end of which is fixedly connected to the outer side of the sound source conduit (1) close to the first end; A reference microphone (4), the reference microphone (4) being fixedly arranged on the sound source conduit (1) and being used for collecting sound pressure level data; A far-field microphone (5), the far-field microphone (5) being used to collect sound pressure level data at a set position; A data acquisition processing unit (6) is electrically connected to the reference microphone (4) and the far-field microphone (5), and the data acquisition processing unit (6) is used to collect detection results of the reference microphone (4) and the far-field microphone (5), and to determine whether the sound field is consistent.

2. The high-precision spherical sound field generation and positioning system with adjustable angle according to claim 1, characterized in that: It also comprises a crossbeam (7) which is arranged horizontally; one end of the connecting member (3) away from the sound source conduit (1) is sleeved on the crossbeam (7) and can rotate around the crossbeam (7); Taking the measuring point as a reference, the horizontal distance between the center line of the crossbeam (7) and the measuring point is: The vertical distance between the center line of the crossbeam (7) and the measuring point is: Wherein, r2 is the distance from the measuring point to the center line of the beam (7); θ1 is the angle between the center line of the sound source duct (1) and the horizontal plane; r is the distance from a given measuring point to the second end of the sound source duct (1); a is the distance from the second end of the sound source duct (1) along its center line to a vertical plane passing through the center line of the beam (7); and b is the distance from the center line of the beam (7) to the center line of the sound source duct (1).

3. The high-precision spherical sound field generation and positioning system with adjustable angle according to claim 1, characterized in that: The number of the reference microphones (4) is at least three; the reference microphones (4) are arranged along the length direction of the sound source duct (1), and the distances between adjacent reference microphones (4) are different.

4. The high-precision spherical sound field generation and positioning system with adjustable angle as claimed in claim 3, characterized in that: The data acquisition processing unit (6) is used to obtain the measurement results of the reference microphone (4) and the far-field microphone (5), and to convert the maximum value of the sound pressure level data in the measurement results of the reference microphone (4) into As a consistency check value; Before the test, the distance of the measuring point of the far-field microphone (5) relative to the second end of the sound source conduit (1) and the angle relative to the center line of the sound source conduit (1) are marked. The sound pressure level data of the measuring point of the microphone at specific frequencies in different experiments are: A correction function for the sound pressure level data measured by the reference microphone (4) and the far-field microphone (5) at different specific frequencies is established: Performing multiple measurements at different frequencies, and obtaining calibration curves of the far-field microphone (5) at corresponding measurement points; In the test, the far-field microphone (5) is adjusted back to the position marked before the test, and it is determined whether the curve obtained by frequency sweeping is consistent with the calibration curve. If they are consistent, the sound field is consistent.

5. The angle-adjustable high-precision spherical sound field generation and positioning system according to claim 2, characterized in that: It also comprises a locking member, which is mounted on the connecting member (3) and is used to lock the crossbeam (7) and the connecting member (3).

6. The angle-adjustable high-precision spherical sound field generation and positioning system according to claim 5, characterized in that: The locking member is a bolt, the bolt is threadedly connected to the locking member, and one end of the bolt can abut against the surface of the crossbeam (7).

7. The angle-adjustable high-precision spherical sound field generation and positioning system according to claim 1, characterized in that: The outer diameter of the straight filtering section (12) gradually decreases in a direction away from the contraction section (11).

8. The angle-adjustable high-precision spherical sound field generation and positioning system according to claim 1, characterized in that: The inner diameter calculation formula of the straight filter section (12) is: Among them, f c is the cut-off frequency of the duct filter section, k mn is the radial wave number under rigid wall conditions, c0 is the speed of sound, and a is the radius of the filter section.

9. The angle-adjustable high-precision spherical sound field generation and positioning system according to claim 1, characterized in that: The length of the sound source conduit (1) is 0.5 to 1.5 meters.

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