The composition of dynamic speakers

Voice coil

1) The specific gravity and conductivity of the voice coil

    Almost all voice coil wires are made of copper wire and aluminum wire, or copper-clad aluminum wire. Their different weights have a direct impact on the efficiency of the portable speaker. The weight of the voice coil conductor is half of the equivalent weight of the vibration system. , the efficiency is the best, and the efficiency of aluminum wire is better than that of copper wire. When the voice coil is heavy, the high-frequency response will be reduced, and the resonance frequency of the high-frequency range will be reduced. Therefore, it is necessary to consider the volume and weight of the voice coil during design, especially for full-band SPK.

2) Points to note when choosing a voice coil during development

#High-frequency unit: small coil diameter, light weight

#Higher power unit: choose a voice coil with a thicker wire diameter, of course, you should choose according to your volume and impedance value

#Subwoofer unit: The first choice for a subwoofer is a voice coil with four layers and a thicker wire diameter, because its weight will affect the resonant frequency F0 of the portable speaker

#Roll size selection: When designing the voice coil towel, it is necessary to leave a relative space for the voice coil to move in the washer and the magnetic gap, so as to reduce the distortion of the portable speaker.

Bomb
1) The role of elastic waves .
    Splashes are also called baffles or dampers. Its function is mainly to play the role of braking and center maint enance.The outer edge of the spring is glued to the pot frame， and the neck of the spring is glued to the voice coil and the neck of the drum paper. It can prevent the voice coil from touching the iron sheet and magnet when it moves in the magnetic gap. The voice coil and drum paper are properly connected to maintain the center.So some people call it a centering support. At the same time，the role of elastic waves also affects various indicators of the portable speaker, including technical parameters such as distortion，F0，and Q value.
2) The material of the elastic wave
    Cotton series, CONEX series，blended, plastic， etc.
3) The evaluation index of EMB:
    Elastic wave coefficient,that is, di splacement. It is to measure the di spl acement of the center of the wave after the unit weight is loaded on the center of the wave. Also known as weight shift.
4) Notes on the use of bullets:

#Aiming at portable speakers with good high frequency requirements, the outer diameter of the elastic wave should choose the smallest specification

#For loudspeakers with high power requirements, the number of yarns of the elastic wave is required to be thicker, with good air permeability and good fatigue resistance.

#The choice of the number of ripples of the elastic wave is in principle the first choice to use the one with more ripples, because the stability will be better.

Basin frame

1) The pot frame is a part for installing vibrating components. Parent for magnetic circuits and other parts. Because the basin frame needs to bear very large vibration during the working process of the portable speaker, resulting in resonance at certain frequencies and affecting the sound quality. First of all, it is necessary to ensure no deformation and no distortion. Therefore, in some pot frames, some sound-absorbing materials or interlayers will be added during the construction process to achieve the desired effect.

2) The shape of the pot stand: square, round, apple-shaped, oval

3) The material of the pot frame: plastic (ABS/HIPS) steel plate (SPCC, S steel, P plate steel, C cold forging, C hardness distinction) aluminum-magnesium alloy.

4) The evaluation standard of the pot frame: the flatness of the pot surface. Highly equipped. The height of the wave surface to the bottom and the space inside.

Diaphragm

1) The vibration plate is one of the main parts of the portable speaker, generally called drum paper or paper cone, it has a decisive influence on the performance and sound quality of the portable speaker. It can be said that "you can't make a good portable speaker without good drum paper".

2) A good HIFI drum paper generally meets the following conditions:

a, the weight should be light: it can improve efficiency and have good transition characteristics;

b, the Yankee coefficient should be large: the bandwidth can be expanded, the transition characteristics are good, and the high frequency is also extended;

c. The internal space should be appropriately large: the division movement can be suppressed to reduce the peaks and valleys of treble resonance, so that the frequency response characteristics are flat and the transition characteristics are good. (Internal space means that after the drum paper is made, the inside of the paper is not pressed to death like a board, but there should be some gaps, which is called "internal loss" in Japanese)

3) Basic production of drum paper carcass

    Raw material pulp and fiber disintegration-dyeing-mixing-papermaking-dehydration-hot pressing or drying-moisture-proof treatment, diameter part (middle hole) and outer diameter forming cutting-edge-packing

4) The shape of drum paper:

a, Anti-parabolic shape b, Linear shape

c, parabolic d, elliptical

5) The role of drum paper edge: (cloth edge, foam edge, rubber edge, PU edge, etc.)

a. For the input power, EGEE drum paper can maintain a better linear motion, and the amplitude is larger than that of the drum paper on the edge of the paper, but the distortion rate is low;

b. The support for the drum paper is more elastic, and it can reduce the bass resonance F0, so that the frequency of the bass's maximum limit frequency is reduced, and the volume of the portable speaker box can be reduced;

c, can reduce the reflected sound wave from the EDGE part, and make the peak and valley surface where the frequency number characteristic is located become flat. So as to obtain a flatter frequency response curve;

Dust cover

    Dust cover is also called hat, dust cover and so on. Its main function is to prevent dust and other sundries from entering the magnetic gap from the real surface of the drum paper to cause abnormal sound, and it also has the function of reinforcing the high-pitched sound. Most of its materials are cloth, paper, PP, metal, etc. For portable speakers with high power and strong vibration, the dust cap generally needs to be thicker to prevent resonance. At the same time, the temperature resistance must be improved. If it is too thin, the high temperature will easily melt the dust cap and cause it to dent.

Terminal

    The terminal is the connection port for connecting brocade wires and signal wires, and it also has a certain impact on HIFI-level portable speakers that require high sound quality.