The working principle of speakers and receivers

1. The working principle of speakers and receivers

We do for the speaker design personnel and technical management personnel, sometimes feel that the speaker although only a dozen parts is not much, but the complex difficult degree far beyond our imagination. This is because: usually the components of the energy conversion usually only once. For example, electric motor is the electric energy conversion to mechanical energy, electric light is the electric energy conversion to light, the battery is chemical energy conversion to electricity, but one kind of energy to another energy conversion. The speaker is different, it is to convert electrical energy into mechanical energy, and mechanical energy is converted into energy, which is not common in many of the transducer. In one speaker, there are electrical, mechanical, and acoustic parts. Nature brings about the complexity and diversity of the system. The speaker vibration is in 3D space with multiple boundary conditions, a variety of materials, a variety of geometric shapes (polyester membrane), so the vibration analysis is very complex, a general mathematical tool has not enough.

In the past, the design method of the speaker mainly uses the equivalent circuit method of the United States white Swiss Nike, what is equivalent circuit method? Because the acoustic radiation force, vibration, electric oscillation of solutions of differential equations is the same, so the mechanical system with circuit instead of using circuit instead of sound system, will be analyzed by circuit theory, we know that this alternative circuit is called equivalent circuit. Using equivalent circuit to analyze the speaker, the theoretical guidance in the experiment, which is the simulation design method.

At present, the advanced design method is the use of design software, the use of computer design: with the finite element method for the analysis and design of speakers, what is called finite element method? The vibration film is composed of many properties of the same and very small units. For each unit, it is the same. The equilibrium equations are established by using the principle of conservation of energy. Thus the vibration characteristics of the whole vibration film is obtained. The finite element method uses the advanced technology of computer, as long as the input of various data, the computer can get the results, so that the design of the speaker becomes a problem of the use of software, the design of the speaker can be calculated. At present there are a variety of software, such as: we are using Femm (magnetic circuit design software system (FINEMotor) and the design of speaker unit magnetic circuit system and a voice coil of Denmark), through the application of these two software, we use design software from a taste of sweetness, but for FINECone (using the the finite element method for the acoustic characteristics of the cone basin and the dome of the diaphragm and the use of simulation software of Denmark) we haven't mastered, so their use also need a period of time. In the domestic speaker design software has been more and more manufacturers recognized and used. We believe that the use of computer aided design of speakers is a wise move, the application of design software will improve product development level, will shorten the product development cycle, reduce costs. We require designers to design the simulation stage as soon as possible transition to the design stage using computer design software, keep pace with the times, improve the design level of the products.

2 The working principle of speakers and receivers

The speaker was invented in 1925, 80 years of speakers in continuous improvement, using a number of new materials, new technology, new structure, new adhesive, so that the speaker's power continues to improve, the work frequency range gradually widened, distortion gradually reduced, in short, the development of the speakers of the technology and the development of the speaker technology to provide new impetus for the development of speakers. For example: the use of NdFeB magnets and polyester film, make the speaker to be compact and lightweight, excellent performance and green chemical products, sophisticated technology in the direction of. At present, the world electronic information industry is undergoing a major technological transformation, which is the transition from analog to digital technology. The speaker's digital is the trend of the times, from the world to see the digital speakers of the design is also more complicated, the cost is high, so it has not been popularized. We present the production and development of speakers are all the use of simulation technology design.

The classification of speakers can be classified by different methods:

According to the principle of work: electric, electromagnetic, piezoelectric, electrostatic...

According to the working frequency band: full band, language, bass, Alto, soprano...

According to the radiation: radiation, horn, headset...

According to the magnetic circuit form: the internal magnetic, magnetic, magnetic, magnetic composite...

According to the shape of the film: plane, the shape of the sun, the shape of the sun, and the shape of the ball,...

According to the material of diaphragm: polyester film, paper pots, aluminum film, titanium film...

All kinds of speakers of the light production are: Electric speakers (including speakers of headphones)

2.1Working principle of electric loudspeaker:

When the speaker is working, we see that the vibration of the diaphragm is in the upper and lower vibration, which makes the vibration of the diaphragm is the electric power, the interaction between the current carrying conductor and the magnetic field, the size of which is:F=BLI

F – Instantaneous value of electric power N

B – Gap magnetic flux density T

L – Voice coil length M

I – Instantaneous current intensity A

The force in the magnetic field of the coil, according to Fleming's law to determine the left hand (see Figure 1). The left hand thumb and other four refers to the vertical lines through the palm, four fingers pointing to the direction of current flow is in the direction of the thumb as the voice coil force direction, if the change in the direction of the current is F, the direction of change. The voice coil in the electric power of the role of the upper and lower motion, driven by the vibration of the paper basin, the speed of the vibration of the paper and the input frequency, the magnitude of vibration and the strength of the input current. When the paper is vibrating, the surrounding air is excited and the sound waves are formed. The conversion of the electric - to - to - force - > sound is accomplished by the speaker.

Figure 1

Light receiver production: all belong to the moving coil receiver.

2.2The working principle of the moving coil receiver:

The working principle of loudspeakers and moving coil receiver is basically the same, it is done by the electric force, sound, two conversion, the electric energy is converted into energy. And the speaker is different: the diaphragm sound is not coupled directly with the air, but on the front and rear out sound hole through the damping radiation out, that is to say the diaphragm sound through acoustic elements (acoustic and acoustic hole) after that we hear the sound. This system is mainly affected by the vibration acoustic impedance control, acoustic impedance increases, the frequency range of acoustic impedance control is wide, so we call the receiver is a damping control element.

We use now the production of mobile phone receiver, due to the use of space and specific requirements and have different receiver structure of the past, for the pedestal after damping is basically no, for the front cover damping are often used in fine mesh, which are actually increases the production difficulty, namely we often speak more simple the structure is more difficult to produce, because components, adjustable volume, the error parameters can compensate each other. For example: the F0 of the diaphragm of the difference, the B value of the magnetic floating can be used to cover up the damping method. So the design staff in the design of the product must be careful for process design, we tell you to leave the rear, to ensure the feasibility of mass production.