The settings for the built-in speakers

Audio electric energy through electromagnetic, piezoelectric or electrostatic effect, make its paper basin or diaphragm vibration and resonance with the surrounding air (resonance) and issued sound, loudspeaker is divided into built-in loudspeaker and external loudspeaker, and external loudspeaker is generally referred to 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.