Working principle of loudspeaker

The electric loudspeaker also known as loudspeakers, it is the application of the principle of electric electroacoustic transducing devices.

It is currently the most widely used, the most widely used speakers, there are three main reasons:

　　1．Electric loudspeaker structure is simple, easy to produce, and itself does not require large space, resulting in a low price, can be a lot of popularity.

　　2．This type of loudspeaker can be done with good performance, and the frequency response can be obtained in the medium frequency band.

　　3．In the continuous improvement of this type of speakers, the development history of speakers for decades, is the speaker design, technology, materials, continuous improvement of the history, but also the performance of the history of the times.

Most of the shape of the electric loudspeaker is a conical, spherical dome; a conical speaker (speaker cone).

The structure can be divided into three parts:

　　1>The vibration system comprises a diaphragm, a voice coil and a centering support chip, dust cover, etc.

　　2>The magnetic circuit system includes a guide plate, a guide plate, a guide plate, a magnet, etc.

　　3>The auxiliary system comprises a frame, a pressing edge and a connection frame, phase turunda.

According to Faraday's law, when the current carrying conductor through a magnetic field, will be affected by a power, its direction to Fleming's left-hand rule of force and current, the magnetic field direction perpendicular to each other, the magnitude of the force and current, magnetic flux density is proportional to the length of the wire. When the voice coil input AC current, the voice coil is subjected to an alternating driving force to produce alternating movement, driven by the paper basin vibration, repeatedly push air and sound.

　　The force that causes the vibration of the electric loudspeaker to vibrate, that is, the magnetic field on the current carrying conductor, which we call the force effect of the electric transducer, the size of which is determined by the following formula:

　　F=B L i

　　Type:BMagnetic induction density (intensity) in the magnetic gap，Its unit is N/（A.m）Also known as Tesla（T）

　　L for voice coil wire length, unit: M

　　I for the current flowing through the voice coil unit: Ampere

　　F for the magnetic field on the voice coil of the force, the unit: Newton

However, in the power of the voice coil force exercise at the same time, due to cuts in the magnetic gap and magnetic induction electromotive force generated in the voice coil, electric effect this effect, we call it the electric transducer, the induction electromotive force for:

е=Вiν

　　In the formula: V is the vibration speed of the voice coil, the unit is: M / S

　　By induction coil EMF, unit: v

　　The electric power effect and the electric effect are simultaneously present, accompanied by the same.

Other speakers working principle:

　〈1〉Loudspeaker: also known as the "Reed loudspeaker", an electromagnet with a movable plunger between the two poles of the permanent magnet, when no current coil of the electromagnet when the movable core is attracted by the permanent magnet magnetic pole two level attraction, remain stationary in the middle; when current flows through the coil, the movable iron core is magnetized, and a bar magnet. With the change of the direction of the current, the polarity of the bar magnet changes, so that the movable core can rotate around the fulcrum, the vibration of the movable core is transmitted by the cantilever to the vibrating film (paper basin).

　〈2〉Electrostatic loudspeaker: it is the speaker uses static electricity to the capacitor plates on the work, its structure, from the positive and negative electrodes are opposite and capacitor, so called capacitor loudspeaker. As shown in figure, there are two thick and hard materials as a fixed plate, the plate can be through the sound, the middle of a plate with a thin and light material for vibrating film (such as aluminum film). The diaphragm, taut and fixed around the fixed pole and at a distance, even in the famous film, will not be fixed and very touching. A DC voltage (called bias) between two electrodes. If the two electrodes are coupled with the output voltage of the amplifier, the output voltage is overlapped to form an alternating current, which is caused by the change of the attraction of the poles. The advantages of the electrostatic speaker is the whole vibration film in phase vibration, the film is light, distortion is small, it can replay the very crisp sound, has a very good analytical, detail, sound fidelity. Its disadvantages are low efficiency, high voltage DC power supply, easy to vacuum, the vibration film will increase the distortion will increase, not suitable for listening to rock, heavy metal music, the price is relatively expensive some.

　〈3〉Piezoelectric speaker: the use of piezoelectric materials for the inverse piezoelectric effect and the work of the speaker called the piezoelectric speaker. The dielectric (such as quartz, potassium sodium tartrate crystals) polarization occurs under pressure to the surface potential at the ends of the phenomenon, known as the "piezoelectric effect". Its inverse effect, that is, in the electric field of the dielectric will occur elastic deformation, known as the "inverse piezoelectric effect" or "electric power". Compared with the electric type loudspeaker, the piezoelectric speaker does not need the magnetic circuit, and compared with the static electricity, the structure is simple and the price is cheap, but the disadvantage is that the distortion is large and the work is not stable.

　〈4〉Ion speakers: in general, the molecular weight of the air is neutral, not charged. But after high pressure discharge, it becomes a charged particle, which is called free. The principle of a sound wave, which is the principle of the ion speakers, is generated by the use of the free air in the audio frequency. In order to be ionized, the high frequency voltage of 20MHz is to be added, and the signal voltage is overlapped on it. Therefore, the high frequency oscillating ion speaker, modulated audio signal, discharge cavity and horn composition. The discharge cavity diameter of 8mm in quartz rod center hole, a quartz tube, an electrode inserted into the other electrode shown in cylindrical sleeve in the quartz tube outside, due to the silent discharge form, only the center of the needle electrode loss, can replace the center electrode regularly. Ion speaker speakers and other difference is that no diaphragm, so the transient characteristics and frequency characteristics are very good, but the structure is too complex.

　〈5〉Flame Speaker: when the air and gas burning flame through the electrode, the electrode with a DC voltage and high frequency signal, the flame is modulated by the audio signal and sound. The flame is almost no mass, and the sound is very dynamic. But it has a fatal flaw: it's not safe, inconvenient.

　〈6〉Air modulated Speaker: also known as air current speaker. It is the use of compressed air as energy, the use of audio frequency current modulation of the voice of the speaker. It consists of a gas chamber, valve, horn and magnetic modulation. Flow of compressed air by gas chamber through the valve, the external modulated audio signal, so that the air flow fluctuates according to the external audio signal, and modulated by air horn coupling, to improve the efficiency of the system. It is mainly used for high intensity noise environment test of sound source or long-distance broadcast, etc..

  〈7〉Magnetic distortion speaker. This is a special kind of strong magnet, which can vibrate under the action of magnetic field.