The speakers are divided into built-in speakers and external speakers

Loudspeaker also known as "horn". Is a very common electroacoustic transducer parts, in the sound of electronic and electrical equipment can be seen in it. The loudspeaker is one of the weakest components in acoustics equipment, but for acoustics, it is one of the most important components. There are many types of speakers and their prices vary widely. Audio electrical energy produces sound by electromagnetic, piezoelectric or electrostatic effects that vibrate the paper bowl or diaphragm and resonate (resonate) with the surrounding air. According to the energy exchange mechanism and structure of moving coil type (electric type), capacitor type (electrostatic type), piezoelectric type (crystal or ceramic), electromagnetic type (pressure spring type), electric ion type and pneumatic loudspeaker, electric loudspeaker has good electroacoustic performance, firm structure, low cost advantages, widely used; According to the sound radiation material, paper basin type, number cylinder type, diaphragm type; According to the shape of the paper basin, it is divided into round, oval, double paper basin and rubber folding ring. According to the working frequency of bass, medium, treble, some also divided into tape recorder special, TV special, ordinary and high fidelity loudspeaker, etc.; The voice coil impedance is divided into low impedance and high impedance; According to the effect, it can be divided into radial and ambient sound. Loudspeaker is divided into built-in loudspeaker and external loudspeaker, and external loudspeaker refers to commonly namely the sound box. Built-in speaker refers to the fact 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. With the built-in speaker MP4 player, you can do not need external speakers, but also can avoid the inconvenience of long time with headphones.