Audio power by electromagnetic or electrostatic, piezoelectric effect, the cone or diaphragm vibration and resonate with the surrounding air (resonance) and sound, built-in speaker and speaker for external speakers, and external speakers that generally refers to the speaker. Built in speaker is a MP4 player with a built-in speaker, so users can not only through the headphone jack can also be through the built-in speaker to listen to the sound of the MP4 player.

音频电能通过电磁，压电或静电效应，使其纸盆或膜片振动并与周围的空气产生共振（共鸣）而发出声音,扬声器分为内置扬声器和外置扬声器，而外置扬声器即一般所指的音箱。内置扬声器是指MP4播放器具有内置的喇叭，这样用户不仅可以通过耳机插孔还可以通过内置扬声器来收听MP4播放器发出的声音。