Manufacturing method of sound radiation unit based on Helmholtz resonator

Abstract

The invention discloses a manufacturing method of a sound radiation unit based on a Helmholtz resonator. The method comprises the following steps: uniformly mixing wood chips, adhesive material particles and a sound absorption coefficient adjusting material; putting the obtained mixture into a hot-press forming machine for hot-press forming; and carrying out surface treatment on the formed structure to obtain the Helmholtz resonator. And the driver is installed on the cavity wall of the Helmholtz resonator, and the sound radiation unit based on the Helmholtz resonator is manufactured. According to the method, the wood chips are used as raw materials, and the sound radiation unit based on the Helmholtz resonator with good sound quality and sound effect can be prepared.

Description

Technical Field

[0001] The present application relates to the field of acoustic technology, and in particular to a method for manufacturing a sound radiation unit based on a Helmholtz resonator. Background Art

[0002] The most common sound radiation unit is the loudspeaker, and most of them are dynamic loudspeakers. The sound-generating principle of this type of electroacoustic device is that it uses the Ampere force on the current-carrying coil (voice coil) in the magnetic field to drive the vibration basin (paper basin, vibration membrane) to vibrate and generate sound. It is also common for other sound radiation units to generate sound by vibrating the vibration basin (paper basin, vibration membrane).

[0003] Existing acoustic systems often use resonance boxes to amplify sound. The erhu, a classic Chinese musical instrument, is a typical example. The erhu first has a vibration generating part, where the bow hair rubs against the strings to generate vibrations. The bridge transmits the vibrations of the strings to the skin of the instrument, causing it to vibrate. The erhu also has a resonance box - the sound box. The vibration of the skin of the instrument drives the air in the sound box to vibrate, thereby amplifying the vibration volume. The amplified sound is transmitted from the sound box through the sound window.

[0004] The Helmholtz resonator is a basic and common resonance box. A common Helmholtz resonator can be composed of a hollow glass or metal ball with a short tube in front to the outside. The principle of the Helmholtz resonator can be based on the vibration of the air piston at the neck to drive the air spring of the spherical cavity. When analogizing the circuit, the end of the short tube becomes the driver of the cavity. From the perspective of acoustic and electrical analogy, it is a simple series circuit. The vibration in the cavity can emit sound waves through the short tube to strengthen the sound field outside and have the function of sound radiation. The working principle of the Helmholtz resonator is based on acoustic resonance. It does not vibrate itself, but the air inside vibrates and has the function of sound radiation. Summary of the invention

[0005] The main technical problem solved by the present application is to provide a method for manufacturing a sound radiation unit based on a Helmholtz resonator.

[0006] The embodiment of the present application provides a method for manufacturing a sound radiation unit based on a Helmholtz resonator, wherein the sound radiation unit based on the Helmholtz resonator comprises a Helmholtz resonator and a driver; the driver is used to apply a vibration signal to the cavity wall of the Helmholtz resonator; the cavity wall of the Helmholtz resonator is used to vibrate under the drive of the vibration signal, so that the air inside the Helmholtz resonator vibrates to emit a first sound wave, and the cavity wall of the Helmholtz resonator itself emits a second sound wave due to the vibration;

[0007] The method comprises:

[0008] Evenly mix wood chips, adhesive material particles and sound absorption coefficient adjusting material;

[0009] The obtained mixture is placed in a hot pressing molding machine for hot pressing molding;

[0010] Performing surface treatment on the formed structure to obtain the Helmholtz resonator;

[0011] The driver is installed on the cavity wall of the Helmholtz resonator to obtain a sound radiation unit based on the Helmholtz resonator.

[0012] In some optional embodiments, the wood chips are redwood wood chips.

[0013] In some optional embodiments, the method further comprises: cleaning, removing impurities, and baking and dehumidifying the wood chips in advance, and screening them using a sieve with a set mesh size.

[0014] In some optional embodiments, the wood chips and the adhesive material particles have comparable particle sizes.

[0015] In some optional embodiments, the adhesive material particles are made of phenolic resin material or thermosetting adhesive material.

[0016] In some optional embodiments, the material for adjusting the sound absorption coefficient is talcum powder or fiber material.

[0017] In some optional embodiments, the Helmholtz resonator is spherical in shape.

[0018] In some optional embodiments, the cavity wall of the Helmholtz resonator is densely covered with pores.

[0019] In some optional embodiments, the Helmholtz resonator comprises:

[0020] A cavity, enclosed by the cavity wall, having an opening;

[0021] a short tube connected to the opening;

[0022] The air inside the cavity vibrates along with the vibration of the cavity wall and emits the first sound wave through the short tube.

[0023] In some optional embodiments, the driver is mounted on the outer surface of the cavity wall and is opposite to the opening position.

[0024] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0025] The present application proposes a method for manufacturing a sound radiation unit based on a Helmholtz resonator, which is used to manufacture a sound radiation unit based on a Helmholtz resonator. The sound radiation unit based on a Helmholtz resonator, on the one hand, utilizes the sound radiation function of the Helmholtz resonator to emit a first sound wave, and on the other hand, utilizes the surface vibration of the cavity wall surface of the Helmholtz resonator under the excitation of a driver to emit a second sound wave, and is a new type of sound radiation unit that combines the above two effects.

[0026] The first feature of this new type of sound radiation unit is that it does not use the vibration of a vibrating basin (paper basin, vibrating membrane) to produce sound, but instead uses a resonator "with a cavity instead of a membrane"; the second feature is that it combines the sound radiation generated by the vibration of the air inside the Helmholtz resonator and the sound radiation generated by the vibration of the cavity wall, thereby improving the sound quality and sound effects; the third feature is that it can use a three-dimensional cavity wall structure to produce sound, exchanging volume for area, and can effectively increase the vibration area when the overall size is similar, thereby improving the sound quality and sound effects.

[0027] In summary, the sound radiation unit of the present application has obvious characteristics and good effects. It can not only be used as a new type of sound radiation unit, but also can be combined into a new type of speaker. It can be derived into applications in electronic music systems and other sound radiation fields, and has a wide range of application scenarios.

[0028] The manufacturing method of the sound radiation unit based on the Helmholtz resonator uses wood chips as raw materials and can manufacture the sound radiation unit based on the Helmholtz resonator with good sound quality and sound effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments and the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 is a schematic diagram of the cross-sectional structure of the sound radiation unit based on the Helmholtz resonator of the present application;

[0031] Figure 2 It is a flow chart of a method for manufacturing a sound radiation unit based on a Helmholtz resonator of the present application. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0033] The terms "first", "second", "third", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0034] The following describes the embodiments in detail.

[0035] refer to Figure 1 , showing a schematic diagram of the cross-sectional structure of the sound radiation unit based on the Helmholtz resonator of the present application.

[0036] like Figure 1 As shown, the sound radiation unit based on the Helmholtz resonator of the present application includes a Helmholtz resonator 10 and a driver 11; wherein the driver 11 is used to apply a vibration signal to the cavity wall 101 of the Helmholtz resonator 10; the cavity wall 101 of the Helmholtz resonator 10 is used to vibrate under the drive of the vibration signal, so that the air inside the Helmholtz resonator 10 vibrates to emit a first sound wave, and the cavity wall 11 of the Helmholtz resonator 10 itself emits a second sound wave due to vibration.

[0037] In some optional embodiments, the Helmholtz resonator comprises:

[0038] The cavity 102 is surrounded by the cavity wall 101 and has an opening 103;

[0039] A short tube 104 connected to the opening 103;

[0040] The air inside the cavity 102 may vibrate along with the vibration of the cavity wall 101 , and may emit a first sound wave through the short tube 104 .

[0041] In some optional embodiments, the driver 11 is mounted on the outer surface of the cavity wall 101 and is opposite to the opening 103 .

[0042] In some optional embodiments, the device further comprises: a bell mouth 12 connected to the short tube 104. The bell mouth 12 can expand the sound wave radiation range, improve the acoustic efficiency, and adjust or improve the frequency response.

[0043] In some optional embodiments, the cavity 102 is in the shape of a sphere, an ellipsoid, a cylinder or other shapes.

[0044] In some optional implementations, there are multiple short tubes 104 with different lengths and / or diameters.

[0045] In some optional embodiments, multiple different parts of the cavity wall 101 vibrate independently to form multiple independent vibration units, and the multiple independent vibration units form an array.

[0046] In some optional embodiments, the cavity wall 101 is made of metal, wood, ceramic, glass, polymer material or other materials.

[0047] In some optional embodiments, the driver 11 is a moving coil driver.

[0048] In some optional embodiments, the first sound wave and the second sound wave are superimposed in phase.

[0049] The above briefly introduces a sound radiation unit based on a Helmholtz resonator proposed in an embodiment of the present application.

[0050] The technical principle of the sound radiation unit of the present application is: first, a resonance box is used to amplify sound, and this resonance box is the Helmholtz resonator; second, the cavity wall of the Helmholtz resonator is used to generate surface vibration under the excitation of the driver to generate sound. Therefore, the present application is a new type of sound radiation unit that combines the two effects of the sound radiation of the Helmholtz resonator itself and the sound generated by the surface vibration of the cavity wall of the Helmholtz resonator under the excitation of the driver.

[0051] Unlike a general Helmholtz resonator that vibrates the air inside the cavity by receiving an external sound source, the present application vibrates the cavity wall of the Helmholtz resonator through driver excitation, and the vibration of the cavity wall causes the air inside the cavity of the Helmholtz resonator to vibrate, thereby achieving the function of sound radiation.

[0052] The principle of the Helmholtz resonator is that the air spring of the spherical cavity can be driven by the vibration of the air piston at the neck. When analogized to the circuit, the end of the short tube becomes the driver of the cavity. Since the end of the short tube becomes the driver of the cavity, the length of the short tube obviously has a significant impact on the sound radiation. In the design, the diameter and length of the short tube must be determined according to the specific acoustic requirements, or multiple short tubes with different diameters and lengths constitute different Helmholtz resonators. In order to facilitate sound radiation, the trumpet that can be used for sound amplification can be connected to the short tube.

[0053] As a Helmholtz resonator, there are many choices for the material of the cavity wall and the volume of the cavity, which can be determined according to specific acoustic requirements, or tone and timbre requirements. The cavity wall can be made of metal, wood, ceramic (including glass), polymer materials, etc. For example, the Helmholtz resonator is composed of a hollow sphere such as a glass ball or a metal ball. The shape is not limited to a sphere, and an ellipsoidal sphere or other deformed spheres are also acceptable. A short tube is added in front of the sphere to the outside, and it can be with or without a neck. In the design, the size of the cavity volume can also be determined according to specific acoustic requirements.

[0054] In addition, the present application causes the cavity wall of the Helmholtz resonator to vibrate on the surface through the excitation of a driver (such as a dynamic coil driver), such as random vibration in a normal vibration mode. The cavity wall surface of the Helmholtz resonator can be regarded as a vibration plate (or diaphragm). Each of the multiple parts of the vibration plate moves independently and is not synchronized with other parts. The entire vibration plate seems to be composed of many micro-unit diaphragms, each of which makes sound independently, and the overall effect forms the overall frequency response characteristics. It is easy to understand that this is an NXT structure, and NXT is a wide-band acoustic radiator. The basic structure of the NXT planar speaker is a driver plus a sound board. This technology completely abandons the design of traditional piston-type motion. The sound board is replaced by a lightweight flat plate or a box shell or a plane. After driving, the entire surface is replaced by a diaphragm that vibrates almost randomly rather than regularly. After it is subjected to a certain excitation, each area unit on the panel can vibrate independently and irregularly, so that the entire panel can be imagined as an array composed of micro-speakers. Each micro-speaker unit radiates an unrelated signal, but their signals are finally synthesized together to form a required acoustic output from a macroscopic perspective. This randomly vibrating plate is very different from a conventional diaphragm because its power is directly output to the plate's mechanical impedance which is constant relative to the frequency. NXT has very good characteristics.

[0055] In addition, the driver of the present application can adopt a dynamic driver. The dynamic driver can be a moving iron that vibrates in a magnetic field system under the action of an external alternating signal, and then acts on the surface of the Helmholtz resonator cavity wall. Under the excitation of the driver, the surface of the Helmholtz resonator cavity wall produces surface vibration and sounds. On the cavity wall surface, surface vibration is generated due to the excitation of the driver, and this surface vibration is a random vibration in a normal vibration mode due to the dynamic drive. After the drive, the entire surface vibrates almost randomly instead of the regular vibration of the diaphragm. After it is stimulated in some way, each area unit on the surface can vibrate independently and irregularly, so that the entire surface panel is conceived as an array composed of micro speakers.

[0056] The characteristic of the sound radiation unit of the present application is that it does not use a vibrating basin (paper basin, vibrating membrane) to vibrate, but uses the air in the cavity of the Helmholtz resonator to vibrate under the excitation of a dynamic driver. Due to the vibration of the air in the cavity, sound waves are emitted through a short tube to strengthen the sound field outside. It has the characteristic of sound radiation with the function of "replacing the membrane with the cavity"; it also uses a dynamic driver to excite the surface of the cavity wall of the Helmholtz resonator. The dynamic driver is a moving iron composed of a permanent magnet that vibrates in a magnetic field system under the action of an external audio signal, and then acts on the surface of the cavity wall of the Helmholtz resonator. Under the excitation of the driver, the surface of the cavity wall of the Helmholtz resonator produces surface vibration and produces sound. On the surface of the cavity wall of the Helmholtz resonator, surface vibration is generated due to the excitation of the driver, and this surface vibration is a random vibration in a normal vibration mode due to the dynamic drive. After the drive, the entire surface vibrates almost randomly, rather than the regular vibration of the diaphragm. After it is subjected to a certain excitation, each area unit on the surface can make independent and irregular vibrations, so that the entire surface panel can be imagined as an array composed of micro speakers.

[0057] refer to Figure 2 The present application also provides a method for manufacturing a sound radiation unit based on a Helmholtz resonator, which is used to prepare the sound radiation unit based on a Helmholtz resonator as described above. The method comprises the following steps:

[0058] S1. Fully and evenly mix wood chips, adhesive material particles and sound absorption coefficient adjustment materials;

[0059] S2, placing the obtained mixture into a hot pressing molding machine for hot pressing molding;

[0060] S3, performing surface treatment on the formed structure to obtain a Helmholtz resonator;

[0061] S4. Install a driver on the cavity wall of the Helmholtz resonator to obtain a sound radiation unit based on the Helmholtz resonator.

[0062] In some optional embodiments, the wood chips are wood chips of high-grade wood such as mahogany. First, the wood chips can be processed from the scraps of high-grade wood (such as mahogany) or from the processing of high-grade wood (such as mahogany).

[0063] In some optional embodiments, the wood chips may be cleaned, impurities removed, and baked and dehumidified in advance, and screened using a sieve with a set mesh size (specification).

[0064] In some optional embodiments, the particle sizes of the wood chips and the adhesive material particles are comparable (matched).

[0065] In some optional embodiments, the adhesive material particles are made of phenolic resin material or thermosetting adhesive material.

[0066] In some optional embodiments, the material for adjusting the sound absorption coefficient is talcum powder or fiber material.

[0067] In some optional embodiments, the control of the average particle size of the wood chips, the control of the particle size of the adhesive material, and the ratio of the material for adjusting the sound absorption coefficient can be designed and controlled according to their acoustic characteristics.

[0068] In some optional embodiments, the cavity wall of the Helmholtz resonator is densely covered with pores.

[0069] For the Helmholtz resonator in the sound radiation unit based on the Helmholtz resonator disclosed above, its material must be strictly selected. There are many options for the material and cavity volume of this Helmholtz resonator, but they must be determined based on specific acoustic requirements, or tone and timbre requirements.

[0070] The method of the embodiment of the present application uses sawdust of wood materials such as redwood, which is screened, classified, glued by special methods, and hot-pressed in one time to form a Helmholtz resonator. It combines the characteristics of high-grade wood and can control its material characteristics. It does not need cutting and processing to form, so the products manufactured can achieve high quality, low price, controllable performance, and convenient manufacturing. Its characteristics are: high density, no material anisotropy, especially the Helmholtz resonator in the new sound radiation unit, which plays a greater role. It uses the sound radiation of the Helmholtz resonator and the surface of the Helmholtz resonator cavity to generate surface vibration under the excitation of the driver to produce sound. The composite sound radiation unit (speaker) has a special function to prevent unnecessary resonance because of its uniform internal material and uniform distribution of small gaps.

[0071] In the above, the technical solution of the present application is described in detail through specific embodiments. In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0072] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. A person skilled in the art may modify the technical solutions described in the above embodiments, or replace some of the technical features therein by equivalents; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and protection scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for manufacturing a sound radiation unit based on a Helmholtz resonator, characterized in that: The sound radiation unit based on the Helmholtz resonator includes a Helmholtz resonator and a driver; the driver is used to apply a vibration signal to the cavity wall of the Helmholtz resonator; the cavity wall of the Helmholtz resonator is used to vibrate under the drive of the vibration signal, so that the air inside the Helmholtz resonator vibrates to emit a first sound wave, and the cavity wall of the Helmholtz resonator itself emits a second sound wave due to the vibration; The method comprises: Evenly mix wood chips, adhesive material particles and sound absorption coefficient adjusting material; The obtained mixture is placed in a hot pressing molding machine for hot pressing molding; Performing surface treatment on the formed structure to obtain the Helmholtz resonator; The driver is installed on the cavity wall of the Helmholtz resonator to obtain a sound radiation unit based on the Helmholtz resonator.

2. The method according to claim 1, characterized in that The sawdust is redwood sawdust.

3. The method according to claim 1, characterized in that Also includes: The sawdust is cleaned, impurities are removed, and the sawdust is baked and dehumidified in advance, and is screened using a sieve with a set mesh number.

4. The method according to claim 1, characterized in that: The particle sizes of the wood chips and the particles of the adhesive material are comparable.

5. The method according to claim 1, characterized in that The adhesive material particles are made of phenolic resin material or thermosetting adhesive material.

6. The method according to claim 1, characterized in that The material for adjusting the sound absorption coefficient is talcum powder or fiber material.

7. The method according to claim 1, characterized in that The Helmholtz resonator is spherical in shape.

8. The method according to claim 1, characterized in that The cavity wall of the Helmholtz resonator is densely covered with pores.

9. The method according to claim 1, characterized in that: The Helmholtz resonator comprises: A cavity, enclosed by the cavity wall, having an opening; a short tube connected to the opening; The air inside the cavity vibrates along with the vibration of the cavity wall and emits the first sound wave through the short tube.

10. The method according to claim 9, characterized in that The driver is installed on the outer surface of the cavity wall and is opposite to the opening position.

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