What a Loudspeaker Needs to Create Sound
- First, speakers need to access the music or movie soundtrack. This is provided in the form of electrical impulses (the audio signal).
- Second, in order for the speaker to take the electrical sound impulses and convert those impulses into an actual sound that you can hear, the speaker needs to be physically connected to an amplifier, which can be powered either by a battery (most applicable for portable devices) or AC power.