Multimedia speakers is how it works

Computer sound files through the sound card, the digital audio signal into an analog audio signal and then its output port, then the audio signal level is weak, usually only a few hundred millivolts, Multimedia Speaker can push the horn work properly. And a working voltage of the speaker driver generally require a voltage of several volts, then a small signal needs to be amplified by the sound output from the amplifier (known as amplifier), the amplified audio signal to the audio speaker driver can convert electrical signals into sound waves a.
And now the latest  Wooden Computer Speaker USB sound card may not be required, it introduces a digital audio signal output of the computer through the USB interface, and USB multimedia speakers this signal through a dedicated internal USB IC chip converts quasi audio signal in order to achieve substituted card function.