The Effect Of Modification On The Structure Of Fiber And Diaphragm Electro-acoustic Performance

A loudspeaker is an electro-acoustic transducer that can convert music electrical signals into sound.The large-diameter loudspeakers on the market today are mainly electro-dynamic loudspeakers and dynamic ring loudspeakers.The electric loudspeaker unit mainly includes three parts,namely a vibration part,a magnetic circuit part,and a suspension part.Distortion of any part will bring distortion of the loudspeaker unit sound quality.The concept of consumption of electronic products has become more and more concentrated,and the pursuit of high-quality sound quality has become even more enthusiastic.Designing and developing high-quality,low-distortion loudspeaker systems is important.With the progress of the manufacturing industry,the production of loudspeaker units has become more and more exquisite,but the sound quality has not improved significantly.The key to designing a high-performance loudspeaker system lies in the improvement of the loudspeaker unit's quality.The most important thing to consider is the cone-diaphragm and the core of the diaphragm design.In addition to the shape and process,it is the material.Diaphragm,also known as the sound film,is the vibration part of the loudspeaker unit.According to its shape or diaphragm material,it can be classified.The shape of the diaphragm used in this paper belongs to the exponential type.The material of the diaphragm belongs to the natural fiber material.The main components of the natural fiber used in the paper diaphragms are more cellulose and lignin,while the hemicellulose is the least.Among them,cellulose is mainly found in the crystalline regions of fibers and the other two substances are mainly found in non-fibrous materials.Crystalline zone,and the presence of lignin affects the binding between fibers.The structural characteristics of the diaphragm material have a great influence on the electro-acoustic characteristics of the entire diaphragm,and the mechanical strength of the diaphragm mainly depends on the hydrogen bonds formed between the cellulose macromolecules and the strength of the fibers themselves.Due to the differences in the distribution of the three substances in the fiber cell wall,the lignin in the fiber can be removed by a modification treatment and the effect on the cellulose is small.The specific research content and main conclusions of this paper:1.The effect of beating physical modification method on the structure of wood fiber and the electro-acoustic characteristics of the diaphragm was studied.By usingSEM,XRD,FTIR-ATR and fiber analyzer,the characterization of the fibers with different beating degrees was performed.The results showed that the surface morphology and morphological structure of the fibers after beating changed,and the chemical composition of the fiber surface also changed.In addition,the mechanical properties and electro-acoustic properties of the diaphragms with different beating degrees were measured using a mechanical analyzer and an electro-acoustic test system.The test results show that the mechanical strength of fiber-diaphragm diaphragm increases with the increase of beating degree,and the mechanical properties of the diaphragm increase fastest when the beating degree is 22°SR,and the tensile strength and burst strength respectively reach 1.23 kN/m and 115 kPa,the effective frequency band of the frequency response curve of the diaphragm is wider than that of the fiber with a beating degree of 16°SR,and the high frequency cut-off frequency reaches 4950 Hz.2.The effects of alkali modification chemical modification method on the structure of wood fiber and the mechanical properties and electro-acoustic properties of the paper diaphragm were studied.The results show that the low concentration of alkali treatment can make the structural characteristics of wood fiber have a greater change,mainly due to the fact that the major component of the wood fiber fiber is less impurities,so it is often used as the main material of the pot.The crystallinity of the fiber after 3 hours of mass fraction of 3%sodium hydroxide solution at room temperature was improved,and the mechanical properties of the treated paper fiber membrane were significantly improved.The high frequency cutoff frequency of the speaker sound pressure frequency response curve was increased by approximately 600.Hz.3.The effects of different chemical modification methods of alkali treatment on the Manila hemp fiber structure and the mechanical properties and electro-acoustic properties of the paper diaphragm were studied.The results showed that with the increase of sodium hydroxide solution mass fraction or treatment time,the surface of fibers became rough,the crystallinity of fibers first increased and then decreased,and the corresponding infrared absorption peaks of lignin and hemicellulose weakened.The thermal stability increases and the thermal stability of the lignin decreases.The crystallinity of the fibers after 5%NaOH solution treatment for 3 h at room temperature was 8%higher than that of the untreated fibers.The tensile strength of the treated paper fiber membranes was 0.59 kN/m greater than that of the untreated fibers,breaking strength increased by 56 kPa,speaker frequency response curve of the part of the unevenness within 2-3 dB,the effective frequency band widening,high frequency limit increased,and softer sound quality.