The main types of loudspeakers

There are many kinds of loudspeakers, according to the principle of energy can be divided into electric (i.e. moving coil type), electrostatic (i.e. capacitance type), electromagnetic (i.e. tongue spring type), piezoelectric (i.e. crystal type), etc., the last two are used in rural cable broadcast network; According to the frequency range can be divided into low frequency speaker, medium frequency speaker, high frequency speaker, these are often used in the speaker box as a combination of speakers.

According to the energy exchange mechanism and structure of movable ring type (electric), capacitive (electrostatic), piezoelectric (crystal or ceramic), electromagnetic (compression spring), electric ion and pneumatic loudspeaker, electric loudspeaker has good electroacoustic performance, solid structure, low cost advantages, widely used;

According to the sound radiation material, paper basin type, cylinder-type, diaphragm type; According to the shape of the paper basin is divided into circular, oval, double paper basin and rubber fold ring; According to the working frequency of bass, alto, treble, some also divided into recorder special, TV special, ordinary and hi-fi speakers; According to the voice coil impedance divided into low impedance and high impedance; According to the effect of direct radiation and environmental sound.

Loudspeaker is divided into built-in loudspeaker and external loudspeaker, and the external loudspeaker is generally referred to as a sound box. Built-in speaker means that the MP4 player has a built-in speaker so that the user can listen to the sound produced by the MP4 player not only through the headphone jack but also through the built-in speaker. The MP4 player with built-in speaker can avoid the need for external speakers and the inconvenience of wearing headphones for a long time.

(1) low frequency loudspeaker

For a variety of different speakers, the low frequency speaker quality factor - Q0 value requirements are different. For closed box and inverted box, Q0 value is generally the best between 0.3 and 0.6. Generally speaking, the larger the caliber, magnet and voice coil diameter of a low-frequency loudspeaker, the better the low-frequency replay performance, transient characteristics, and the higher the sensitivity. The structure of the bass unit is mostly cone type, but also a small number of plate type. There are many kinds of diaphragm for bass unit, such as aluminum alloy diaphragm, aluminum magnesium alloy diaphragm, ceramic diaphragm, carbon fiber diaphragm, bulletproof cloth diaphragm, glass fiber diaphragm, propylene diaphragm, paper diaphragm and so on. The bass unit of aluminum alloy diaphragm and glass fiber diaphragm is generally small in caliber and large in power, while the bass unit of reinforced paper basin and glass fiber diaphragm is more accurate in timbral tone and good in overall balance.

Q0: The quality factor of the speaker unit is a very important parameter that must be understood before the design and production of the speaker. In the speaker unit impedance characteristic curve it says, impedance curve at resonant frequency impedance peak sharpness, it reflects the damping state of the loudspeaker vibration system to a certain extent, Q0 value, the higher the quality factor of the loudspeaker unit, the more difficult to control the resonant frequency. The low frequency characteristics of the loudspeaker are usually determined by the quality of the loudspeaker unit due to the numerical value and the resonant frequency, where the size of the quality factor is related to the sound pressure output of the loudspeaker unit at the resonant frequency. When the value of Q0 is too low, the output sound pressure of the speaker has not reached F0, and the speaker is in a state of over-damping, resulting in excessive low frequency attenuation. When the value of Q0 is too high, the loudspeaker is in the underdamping state, and the low frequency is excessively strengthened. The higher the value of Q0, the steeper the peak. Therefore, we say that the quality factor of the loudspeaker can not be too high or too low, usually we take its critical damping value Q0 is equal to 0. 5 minus 0. 7 is the best value range.

(2) medium frequency loudspeaker

In general, as long as the frequency response curve is flat, the effective frequency response range is greater than the width of the sound band it bears in the system, impedance and sensitivity and low frequency unit can be consistent. Sometimes the power capacity of the baritone is not enough, it is also possible to choose a baritone with a higher sensitivity and a higher impedance than the bass unit, thus reducing the actual input power of the baritone unit. Tenor unit generally has cone and ball top two kinds. It is just that its size and power are larger than the tweeter unit and suitable for playing audio. Alto unit of the diaphragm to the paper basin and silk film and other soft materials, occasionally there is a small amount of alloy ball top diaphragm.

(3) high-frequency loudspeaker

The treble unit is, as the name suggests, a speaker unit designed to play back high frequency sounds. Its structure mainly has the number solution type, cone type, ball top type and aluminum belt type and so on.