CN116847261A

CN116847261A - High-precision laser resonance testing device for diaphragm

Info

Publication number: CN116847261A
Application number: CN202310541073.0A
Authority: CN
Inventors: 陈朝方
Original assignee: Ningbo Tengchen Electronics Co ltd
Current assignee: Ningbo Tengchen Electronics Co ltd
Priority date: 2023-05-15
Filing date: 2023-05-15
Publication date: 2023-10-03

Abstract

The utility model relates to the technical field of laser detection, in particular to a high-precision laser resonance testing device for a diaphragm, which comprises a bracket and also comprises a laser beam; the multifunctional clamp comprises a fine tuning plate, an outer cover is fixedly arranged on the surface of the fine tuning plate, an inner container is integrally arranged in the outer cover, a sound channel is arranged on one side of the inner container, a loudspeaker is inserted and arranged in the inner container, a tympanic membrane is arranged in the middle of a sealing plate, a resonant plate is arranged in the middle of the tympanic membrane, and a membrane is arranged in the middle of the resonant plate; the surface cover of closing plate installs the apron, and the centre of apron is provided with the preforming, and the peripheral position of apron is provided with the screw, and the internally mounted of screw has the locking bolt, locking bolt fixed mounting at the closing plate. The device uses the special clamping effect of the multifunctional clamp, irradiates the membrane resonance process by laser, checks and plots the reflected laser signals, and finally prepares the resonance effect of different types of membranes in the sounding state.

Description

High-precision laser resonance testing device for diaphragm

Technical Field

The utility model relates to the technical field of laser detection, in particular to a high-precision laser resonance testing device for a diaphragm.

Background

Diaphragm of various speakers: in the acoustic field, a diaphragm is a transducer intended to convert mechanical vibrations into sound and vice versa. It is generally composed of a film or sheet of various materials suspended from its edges. The varying acoustic wave air pressure causes the vibrating diaphragm to mechanically vibrate, which can then be converted into other types of signals. Examples of such diaphragms are found in microphones and human eardrums. Instead, a diaphragm vibrated by an energy source impinges on air, creating sound waves. Examples of such diaphragms are loudspeaker diaphragms and earphone air horns, which have diaphragms and diaphragms. The membrane resonates during the transmission of audio due to its own characteristics, which is the primary source of audio or music.

The utility model provides a loudspeaker testing arrangement that publication number is CN210225753U chinese patent discloses, this patent is including being used for holding the test box of speaker and being used for the drive the control box of speaker, be provided with sound absorbing material on the inner wall of test box, be provided with a plurality of baffle in the test box, all the baffle distributes the week side of speaker, and arbitrary two the extending direction of baffle is all different, every the baffle be provided with a adapter on one side of speaker dorsad, all the adapter with control box electric connection. The utility model provides the loudspeaker testing device, which has richer and more accurate testing results and can test a plurality of loudspeakers simultaneously by using a plurality of testing devices.

The testing device of the loudspeaker transfer diaphragm in the prior art needs to use a tooling fixture to clamp the diaphragm in the testing process. However, the fixture in the prior art can only adaptively clamp the diaphragm with a specific size, and the effect of adaptively clamping the diaphragms with different models and sizes is difficult to realize, so that the detection application range of the detection device is affected.

Disclosure of Invention

The utility model aims to provide a diaphragm high-precision laser resonance testing device so as to solve the problems in the background technology.

The technical scheme of the utility model is as follows: a high-precision laser resonance testing device for a diaphragm comprises a bracket and also comprises a support;

the multifunctional clamp comprises a fine tuning plate, wherein an outer cover is fixedly arranged on the surface of the fine tuning plate, an inner container is integrally arranged in the outer cover, a sound channel is arranged on one side of the inner container, a loudspeaker is inserted and arranged in the inner container, the side edge of the loudspeaker is fixedly arranged on the surface of the sound channel through a screw, a support column is arranged at the peripheral part of the fine tuning plate, a sealing plate is arranged on the surface of the support column, sealing plates are arranged at the edge openings of the inner container and the outer cover in a sealing manner, a tympanic membrane is arranged at the middle part of the sealing plate, a resonant piece is arranged at the middle part of the tympanic membrane, and a diaphragm is arranged at the middle part of the resonant piece;

the surface cover of closing plate installs the apron, and the centre of apron is provided with the preforming, and the peripheral position of apron is provided with the screw, and the internally mounted of screw has the locking bolt, and locking bolt fixed mounting is provided with the shot hole at the middle part of preforming on the surface of closing plate, and the shot hole aligns the setting with the diaphragm.

Further technical scheme, the appearance structure of dustcoat is circular drum form hollow structure, and the structure of inner bag is back taper hollow structure, and the structure of acoustic channel is circular opening, and the diameter of acoustic channel is unanimous with the terminal surface diameter of speaker, and the material of preforming is high elasticity high toughness material, and the central part of preforming is provided with the centre gripping cavity.

Further technical scheme still includes:

the device comprises a transverse fine adjustment component, wherein the transverse fine adjustment component comprises an L-shaped frame which is sleeved and installed on the surface of a fine adjustment plate, a slotted hole is formed in one side of the L-shaped frame, the fine adjustment plate is inserted and installed in the slotted hole in a plugging mode, a fixing piece is installed on the surface of the L-shaped frame in a locking mode, a telescopic rod is fixedly installed on one side of the L-shaped frame, a spiral micrometer is installed on one side of the telescopic rod, displacement scales are arranged on the surface of the spiral micrometer, and a base plate is installed on one side of the spiral micrometer.

Further technical scheme still includes:

the longitudinal assembly comprises a movable plate arranged on one side of the base plate, sliding plates are sleeved on two sides of the movable plate, the movable plate is slidably arranged in the sliding plates, and a driving piece is arranged at the bottom of the movable plate.

Further technical scheme, the driving piece is including installing the moving platform in the movable plate bottom, and the chain is installed in moving platform's bottom transmission, and the motor is installed in one side transmission of chain, and the frame is installed in the outside of motor and chain.

Further technical scheme still includes:

the servo control unit comprises a switch power supply arranged on one side of the skateboard, a collinear terminal is connected with one side of the switch power supply, a PLC is connected with one side of the collinear terminal, a transformer is further connected with one side of the switch power supply, and one side of the switch power supply is externally connected with industrial power.

Further technical scheme still includes:

the laser component comprises a laser controller which is connected with one side of the collinear terminal, a laser transmitter is arranged on one side of the bracket, a laser recoverer is arranged on one side of the laser transmitter, and the laser transmitter and the laser recoverer are respectively connected with the PLC through the collinear terminal.

According to a further technical scheme, the center of the laser transmitter is respectively in a straight line with the irradiation hole, the diaphragm, the sound channel and the loudspeaker.

The utility model provides a diaphragm high-precision laser resonance testing device through improvement, which has the following improvement and advantages compared with the prior art; aiming at the technical defects of the loudspeaker transfer diaphragm in the prior art, the device provides a corresponding solution:

firstly, in order to solve the technical defect that the membrane cannot be adapted to membranes of different types in the clamping process, a multifunctional clamp is designed: wherein, the function of the fine adjustment plate is to cooperate with the horizontal fine adjustment assembly to realize the fine adjustment of the horizontal position; meanwhile, the fine adjustment plate is also a mounting base of the clamp. To achieve resonance of the diaphragm, a loudspeaker is first mounted on the surface of the trimming plate. The audio vibration emitted by the loudspeaker needs to be fully utilized to improve the detection effect, so that a double-layer echo sleeve structure is sleeved and installed on the surface of the loudspeaker, namely, the outer layer is designed into a drum-shaped outer cover, and the echo effect of the audio is guaranteed to the greatest extent; the inner side structure directly connects the loudspeaker at the sound channel part through the screw, wherein the cone structure of the inner container can avoid the loss of sound energy. The structure realizes the effect of utilizing the audio frequency of the loudspeaker to the maximum extent.

Secondly, in order to output the audio to the surface of the diaphragm to the greatest extent, a sealing plate is arranged on the surfaces of the liner and the outer cover in a sealing way, and a tympanic membrane and a resonance plate are arranged in the central part of the sealing plate; once the loudspeaker is started, the eardrum and the resonant sheet vibrate, and then the diaphragm on the surface of the resonant sheet is driven to resonate, so that the subsequent detection effect is facilitated.

Thirdly, in order to adapt to the clamping of the diaphragms with different models and sizes, a cover plate is designed, a round hole is drilled in the middle of the cover plate, a pressing sheet with elastic and tough materials is arranged in the round hole, when the diaphragms with different models and sizes are placed at the lower part of the pressing sheet, the clamping adjustment of the suitability can be automatically carried out, then the rigid clamping effect of the locking bolts at the periphery is matched, and the dual stable adaptive clamping effect is realized.

Fourthly, in order to conveniently realize the adjustment of the alignment center in the detection process, a transverse fine adjustment assembly and a longitudinal assembly are also designed; the fine adjustment plate of the clamp is inserted and installed in the slot hole of the L-shaped frame by the transverse fine adjustment assembly, and the fixing is realized through the fixing piece. The structure of L type frame has stability for the regulation precision is higher. The effect of controllable fine adjustment scale is realized through the mode that the screw micrometer arranged on the side edge is screwed into the telescopic rod. In the longitudinal direction, the chain transmission on the frame is controlled by the motor, so that the clamp on the mobile platform is driven to realize the effect of position change.

Fifthly, the device realizes the integrated electric control effects of position adjustment and laser irradiation-reflection signal recovery detection through the servo control unit and the laser component. The servo module has the effect of high-precision stepping adjustment, and after the adjustment is finished, real-time detection of the diaphragm resonance effect can be realized through PC end verification of the diaphragm surface resonance laser signal.

Drawings

The utility model is further explained below with reference to the drawings and examples:

FIG. 1 is a schematic perspective view of the present utility model;

FIG. 2 is a schematic perspective view of the multifunctional clamp of the present utility model;

FIG. 3 is a schematic perspective exploded view of the multifunctional clamp of the present utility model;

FIG. 4 is a schematic perspective view of a longitudinal assembly of the present utility model;

FIG. 5 is a schematic perspective view of a driving member of the present utility model;

FIG. 6 is a schematic perspective view of a servo control unit according to the present utility model;

fig. 7 is a schematic perspective view of a laser assembly according to the present utility model.

Reference numerals illustrate:

1. a bracket; 2. a multifunctional clamp; 3. a lateral fine adjustment assembly; 4. a longitudinal assembly; 5. a laser assembly; 6. a servo control unit; 7. a fine tuning plate; 8. an outer cover; 9. a speaker; 10. a screw; 11. an inner container; 12. a sound channel; 13. a support column; 14. a sealing plate; 15. a tympanic membrane; 16. a resonator plate; 17. a membrane; 18. a cover plate; 19. a screw hole; 20. a locking bolt; 21. tabletting; 22. an irradiation hole; 23. a screw micrometer; 24. a telescopic rod; 25. an L-shaped frame; 26. a slot hole; 27. a fixing member; 28. a moving plate; 29. a slide plate; 30. a driving member; 31. a motor; 32. a frame; 33. a chain; 34. a mobile platform; 35. a laser recoverer; 36. a laser emitter; 37. a switching power supply; 38. collinear terminals; 39. a PLC; 40. a laser controller; 41. a transformer.

Detailed Description

The following detailed description of the present utility model clearly and fully describes the technical solutions of the embodiments of the present utility model, and it is apparent that the described embodiments are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the description of the present utility model, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are based on directions or positional relationships shown in the drawings, are merely for convenience of description and simplification of description, and do not indicate or imply that the apparatus or element to be referred to must have a specific direction, be constructed and operated in the specific direction, and thus should not be construed as limiting the present utility model; the terms "first," "second," "third," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance, and furthermore, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "coupled," and the like are to be construed broadly, and may be fixedly coupled, detachably coupled, or integrally coupled, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Embodiment one:

the utility model provides a diaphragm high-precision laser resonance testing device through improvement, which comprises the following technical scheme:

as shown in fig. 1-4: a high-precision laser resonance testing device for a diaphragm comprises a bracket 1 and also comprises a bracket; the multifunctional clamp 2 comprises a fine tuning plate 7, an outer cover 8 is fixedly arranged on the surface of the fine tuning plate 7, an inner container 11 is integrally arranged in the outer cover 8, a sound channel 12 is arranged on one side of the inner container 11, a loudspeaker 9 is inserted and installed in the inner container 11, the side edge of the loudspeaker 9 is fixedly arranged on the surface of the sound channel 12 through a screw 10, a supporting column 13 is arranged at the peripheral part of the fine tuning plate 7, a sealing plate 14 is arranged on the surface of the supporting column 13, the sealing plate 14 is hermetically installed at the edge of the inner container 11 and the outer cover 8, a tympanic membrane 15 is arranged at the middle part of the sealing plate 14, a resonant piece 16 is installed at the middle part of the tympanic membrane 15, and a diaphragm 17 is placed at the middle part of the resonant piece 16; the surface of closing plate 14 is covered and is installed apron 18, and the centre of apron 18 is provided with preforming 21, and the periphery position of apron 18 is provided with screw 19, and the internally mounted of screw 19 has locking bolt 20, and locking bolt 20 fixed mounting is at the surface of closing plate 14, and the intermediate position of preforming 21 is provided with the irradiation hole 22, and irradiation hole 22 and diaphragm 17 align to be set up.

A diaphragm high-precision laser resonance testing device is characterized in that the appearance structure of an outer cover 8 is a round drum-shaped hollow structure, the structure of an inner container 11 is an inverted cone-shaped hollow structure, the structure of a sound channel 12 is a round opening, the diameter of the sound channel 12 is consistent with the diameter of the end face of a loudspeaker 9, a pressing sheet 21 is made of high-elasticity high-toughness materials, and a clamping cavity is formed in the central position of the pressing sheet 21.

Working principle: in order to solve the technical defect that the membrane 17 cannot be adapted to different types of membranes 17 in the clamping process, we design a multifunctional clamp 2: wherein, the function of the fine adjustment plate 7 is to cooperate with the transverse fine adjustment component 3 to realize fine adjustment of the transverse position; at the same time, the trimming plate 7 is also the mounting base of the present clamp. To achieve resonance of the diaphragm 17, a loudspeaker 9 is first mounted on the surface of the trimming plate 7. The audio vibration emitted by the loudspeaker 9 needs to be fully utilized to improve the detection effect, so that a double-layer echo sleeve structure is sleeved and installed on the surface of the loudspeaker 9, namely, the outer layer is designed into a drum-shaped outer cover 8, so that the echo effect of the audio can be ensured to the greatest extent; the inner structure directly connects the loudspeaker 9 to the sound channel 12 through the screw 10, wherein the conical structure of the inner container 11 can avoid the dissipation of sound energy. The above structure achieves the effect of maximum audio utilization of the speaker 9.

In order to output the audio to the surface of the diaphragm 17 to the greatest extent, a sealing plate 14 is arranged on the surfaces of the liner 11 and the outer cover 8 in a sealing way, and a tympanic membrane 15 and a resonance plate 16 are arranged in the central part of the sealing plate 14; once the loudspeaker 9 is started, the tympanic membrane 15 and the resonant sheet 16 vibrate, so that the diaphragm 17 on the surface of the resonant sheet 16 is driven to resonate, and the subsequent detection effect is facilitated.

In order to adapt to the clamping of the diaphragms 17 with different models and sizes, a cover plate 18 is designed, a round hole is drilled in the middle of the cover plate 18, a pressing piece 21 made of elastic and tough materials is arranged in the round hole, when the diaphragms 17 with different models and sizes are placed at the lower part of the round hole, the clamping adjustment of the suitability can be automatically carried out, and then the effect of dual-stability adaptive clamping is realized by matching with the rigid clamping effect of the locking bolts 20 at the periphery.

Embodiment two:

as shown in fig. 1-7: a high-precision laser resonance testing device for a diaphragm further comprises: the horizontal fine adjustment component 3, the horizontal fine adjustment component 3 is including cup jointing the L type frame 25 of installing at the fine setting board 7 surface, one side of L type frame 25 is provided with slotted hole 26, and fine setting board 7 grafting is installed in the inside of slotted hole 26, and the fixed part 27 is installed in the surface locking of L type frame 25, and one side fixed mounting of L type frame 25 has telescopic link 24, and spiral micrometer 23 is installed to one side of telescopic link 24, and the surface of spiral micrometer 23 is provided with the displacement scale, and the base plate is installed to one side of spiral micrometer 23.

A high-precision laser resonance testing device for a diaphragm further comprises: the longitudinal assembly 4, the longitudinal assembly 4 includes the movable plate 28 of installing in base plate one side, and the both sides of movable plate 28 cup joint and install slide 29, and movable plate 28 slidable mounting is in the inside of slide 29, and drive piece 30 is installed to the bottom of movable plate 28. The driving member 30 includes a moving platform 34 mounted at the bottom of the moving plate 28, a chain 33 is mounted at the bottom of the moving platform 34 in a transmission manner, a motor 31 is mounted at one side of the chain 33 in a transmission manner, and a frame 32 is mounted at the outer sides of the motor 31 and the chain 33.

In the embodiment of the scheme, in order to conveniently realize the adjustment of the alignment center in the detection process, a transverse fine adjustment assembly 3 and a longitudinal assembly 4 are also designed; the transverse fine adjustment assembly 3 is used for inserting and installing the fine adjustment plate 7 of the clamp into the slot 26 of the L-shaped frame 25, and fixing the fine adjustment plate by the fixing piece 27. The structure of the L-shaped frame 25 has stability so that the adjustment accuracy is higher. The effect of controllable fine adjustment scale is realized by the mode that the screw micrometer 23 arranged on the side edge is screwed into the telescopic rod 24. In the longitudinal direction, the motor 31 controls the chain 33 on the frame 32 to drive the clamp on the moving platform 34 to realize the effect of position change.

As shown in fig. 1-7, a high-precision laser resonance testing device for a diaphragm comprises a servo control unit 6, wherein the servo control unit 6 comprises a switch power supply 37 arranged on one side of a slide plate 29, a collinear terminal 38 is arranged on one side of the switch power supply 37 in a connected mode, a PLC39 is arranged on one side of the collinear terminal 38 in a connected mode, a transformer 41 is arranged on one side of the switch power supply 37 in a connected mode, and industrial power is externally connected to one side of the switch power supply 37.

A high-precision laser resonance testing device for a diaphragm further comprises: the laser assembly 5, the laser assembly 5 includes a laser controller 40 mounted on one side of the collinear terminal 38, a laser transmitter 36 is mounted on one side of the bracket 1, a laser recoverer 35 is mounted on one side of the laser transmitter 36, and the laser transmitter 36 and the laser recoverer 35 are respectively connected with a PLC39 through the collinear terminal 38. The center of the laser transmitter 36 is aligned with the illumination aperture 22, the diaphragm 17, the acoustic channel 12 and the speaker 9, respectively.

In the embodiment of the scheme, the device realizes the integrated electric control effects of position adjustment and laser irradiation-reflected signal recovery detection through the servo control unit 6 and the laser component 5. The servo module has the effect of high-precision stepping adjustment, and after the adjustment is finished, the real-time detection of the resonance effect of the diaphragm 17 can be realized through the PC end verification of the resonance laser signal on the surface of the diaphragm 17.

The core working principle of the device is as follows:

the special clamping effect of the multifunctional clamp 2 is utilized, the reflected laser signals are verified and drawn through the irradiation of laser to the resonance process of the diaphragm 17, and finally the resonance effect of the diaphragms 17 in different types under the sounding state is manufactured.

Finally, it should be noted that: the foregoing description is only illustrative of the preferred embodiments of the present utility model, and although the present utility model has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements or changes may be made without departing from the spirit and principles of the present utility model.

Claims

1. The utility model provides a diaphragm high accuracy laser resonance testing arrangement, includes support (1), its characterized in that: also comprises;

the multifunctional clamp (2), the multifunctional clamp (2) comprises a fine tuning plate (7), an outer cover (8) is fixedly arranged on the surface of the fine tuning plate (7), an inner container (11) is integrally arranged in the outer cover (8), a sound channel (12) is arranged on one side of the inner container (11), a loudspeaker (9) is inserted and connected in the inner container (11), the side edge of the loudspeaker (9) is fixedly arranged on the surface of the sound channel (12) through a screw (10), a supporting column (13) is arranged at the peripheral part of the fine tuning plate (7), a sealing plate (14) is arranged on the surface of the supporting column (13), the sealing plate (14) is arranged at the edge of the inner container (11) and the outer cover (8) in a sealing mode, a tympanic membrane (15) is arranged at the middle part of the sealing plate (14), a resonant piece (16) is arranged at the middle part of the tympanic membrane (16), and a diaphragm (17) is arranged at the middle part of the resonant piece (16).

The sealing plate is characterized in that a cover plate (18) is mounted on the surface of the sealing plate (14) in a covering manner, a pressing sheet (21) is arranged in the middle of the cover plate (18), a screw hole (19) is formed in the peripheral portion of the cover plate (18), a locking bolt (20) is mounted in the screw hole (19), the locking bolt (20) is fixedly mounted on the surface of the sealing plate (14), an irradiation hole (22) is formed in the middle of the pressing sheet (21), and the irradiation hole (22) is aligned with the diaphragm (17).

2. The high-precision laser resonance testing device for the diaphragm according to claim 1, wherein: the structure of the outer cover (8) is a round drum-shaped hollow structure, the structure of the liner (11) is an inverted cone-shaped hollow structure, the structure of the sound channel (12) is a round opening, the diameter of the sound channel (12) is consistent with the diameter of the end face of the loudspeaker (9), the material of the pressing sheet (21) is a high-elasticity high-toughness material, and a clamping cavity is formed in the central part of the pressing sheet (21).

3. The high-precision laser resonance testing device for a diaphragm according to claim 1, further comprising:

the horizontal fine adjustment assembly (3), horizontal fine adjustment assembly (3) are including cup jointing L type frame (25) of installing on fine setting board (7) surface, one side of L type frame (25) is provided with slotted hole (26), fine setting board (7) are pegged graft and are installed in the inside of slotted hole (26), fixed part (27) are installed in the surface locking of L type frame (25), one side fixed mounting of L type frame (25) has telescopic link (24), spiral micrometer (23) are installed to one side of telescopic link (24), the surface of spiral micrometer (23) is provided with the displacement scale, the base plate is installed to one side of spiral micrometer (23).

4. A diaphragm high precision laser resonance testing apparatus as set forth in claim 3, further comprising:

the vertical component (4), vertical component (4) are including installing movable plate (28) in base plate one side, slide (29) have been cup jointed to the both sides of movable plate (28), movable plate (28) slidable mounting is in the inside of slide (29), driving piece (30) are installed to the bottom of movable plate (28).

5. The high-precision laser resonance testing device for the diaphragm according to claim 4, wherein: the driving piece (30) comprises a moving platform (34) arranged at the bottom of the moving plate (28), a chain (33) is arranged at the bottom of the moving platform (34) in a transmission mode, a motor (31) is arranged at one side of the chain (33) in a transmission mode, and a rack (32) is arranged outside the motor (31) and the chain (33).

6. The device for high precision laser resonance testing of a diaphragm as set forth in claim 4, further comprising:

the servo control unit (6), servo control unit (6) are including installing switching power supply (37) in slide (29) one side, collinear terminal (38) are installed in one side switch-on of switching power supply (37), PLC (39) are installed in one side switch-on of collinear terminal (38), transformer (41) are installed in one side switch-on of switching power supply (37) still, the external industrial electricity of one side of switching power supply (37).

7. The device for high precision laser resonance testing of a diaphragm as set forth in claim 6, further comprising:

the laser assembly (5), laser assembly (5) are including switch-on install laser controller (40) in collinearly terminal (38) one side, laser emitter (36) are installed to one side of support (1), laser recoverer (35) are installed to one side of laser emitter (36), laser emitter (36) and laser recoverer (35) are put through with PLC (39) through collinearly terminal (38) respectively.

8. The high-precision laser resonance testing device for the diaphragm according to claim 7, wherein: the centers of the laser transmitters (36) are respectively in a straight line with the irradiation hole (22), the diaphragm (17), the sound channel (12) and the loudspeaker (9).