Working principle of all kinds of speakers

{one} magnetic loudspeaker: also known as reed Speaker its structure as shown in Figure 4, in the permanent magnet poles between a movable iron core of the electromagnet, when no current in the coil of the electromagnet, permanent magnets, magnetic poles level attraction attraction by the movable iron core, in the central remain stationary; when in the current flowing through the coil, a movable core is magnetized, and become 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).

{two} Electrostatic loudspeaker: it is by added to the capacitor plate on the static electricity and the speaker, the structure, a capacitor like from the positive and negative electrodes are opposite, so it is also called as condenser 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). Will diaphragm fixed around, taut and with fixed pole to maintain a considerable distance, even in the large diaphragm on, nor cause the collision with the fixed pole.

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.

{three} Piezoelectric speaker: the use of piezoelectric materials for the inverse piezoelectric effect and the work of the speaker called the piezoelectric speaker. Dielectric (such as quartz and sodium potassium tartrate crystal) under the pressure of polarization potential difference between the two surfaces of the phenomenon, known as the piezoelectric effect. Its inverse effect, that is, in the electric field of the dielectric will occur in elastic deformation, called the inverse piezoelectric effect or electric. 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.

{four} 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. Visible, ion loudspeaker is composed of high-frequency oscillation, modulated audio signal, discharge cavity and horn composition.