Speaker's classification?

The speakers are divided into the built-in speakers and external speakers and external speakers that generally refers to the speaker. The built-in speakers are MP4 player with built-in speakers, so users can not only through the headphone jack is also available through the built-in loudspeaker to listen to your MP4 Player. Has a built-in speaker for MP4 Player, could have an external speaker, you can avoid a long wear headphones the inconvenience.