What is an amplifier?
If you have ever been to a rock concert, a cinema or just listened to music on the way to work, you have used an amplifier. Amplifiers can come in many forms. Everything from the small earplugs you use with your MP3 player to the earthquake surround sound system in an IMAX theater are all amplifiers. Their main task is to simply take a sound (a voice, a sound effect, a musical instrument) and make it louder. Some amplifiers manipulate the sound as it reproduces. A guitar can use its amplifier to add distortion or reverb to its guitar sound. Others may use smoothing to add base to a rattling movie experience. However, the bottom line is amplifiers are all about volume.
Move air
The most important thing needed to amplify the sound is air. The amplifier or amplifier picks up an audio signal and vibrates the speaker inside. This vibration moves the air around the speaker. Your ear perceives this as audible sound. In fact, the human ear itself functions in the same way. Your drum oscillates with the vibrations it receives and sends these signals to your brain as sound. The more power an amp has, the more air it can move and thus create a louder sound. So we know that amperes need to move air to amplify audio signals. But how is the signal in the first place?
Power failure
Amplifier reproduces audio signals that it receives via an electrical signal. When you speak into a microphone, your voice vibrates a small membrane inside. The microphone generates an electrical impulse that fluctuates with these vibrations and sends them through a wire in the amplifier. At this point, the amplifier increases its strength signal by passing it through tubes and / or transistors. The amount of signal increased is based on the wattage of the amplitude and the size of the speaker you are trying to vibrate. The newly illuminated signal is now translated back into vibration and emitted as audible sound through the speaker. It is important to know how much a speaker can take. If the signal output is too high for a given speaker, it can literally tear the speaker apart.
Source:danspela.com