A set of basic playback system are composed by three parts, the sound source, the power amplifier and the speaker box.The sound source currently can be the deck, CD/DVD,redio, MD or even the MP3,etc.Power amplifier deals with the outut signals from the sound source,especially does the work of pre-processing,mixing,shunt and the current amplification.Speaker box is the sound equopment, and also the terminal device of the acoustics system.Those speaker boxes which are built in with amplifiers, as long as they can playback when connecting to the sound source then they'll be called the active speakers.If the sound source, the power amplifier and the speaker box are all independent of their own, then they'll be call the "stereo mix".Speaker is an integral part of the acoustics, and the acoustics is the general designation of the sound reduction/playback system.


