The Basic Design
While there are many different designs for bass guitars, they all work pretty much the same. The strings vibrate, the sound is picked up and transmitted, and the amplifier makes the sound louder. The key to understanding how an electric bass guitar works is to follow the signal path as closely as possible, from string to pickup to amplifier.
The Strings: Where it All Starts
The fanciest electronics and the flashiest paint job aren't going to do you any good if you don't have strings on your bass. The strings are what actually make the sound in the first place. When a string is plucked, it vibrates. The thickness of the string and the tension to which it is pulled determine what note is played and the quality, or timbre (pronounced TAM-ber) of the note. Try playing the open G string and then playing the fifth fret of the second string. They are the same note, but there is a difference in the sound quality. That is the difference that string thickness makes.
The strings of an electric bass guitar are usually made from a steel or nickel core, then wound with steel or some other magnetic metal. When the string vibrates, it creates a magnetic field with specific characteristics.
The Pickups: The Next Stop
Once the strings are vibrating and creating their own unique and distinctive magnetic field, the pickups do what they're named for: picking up the signal. A standard magnetic pickup is made of one or more magnets that have been wrapped in copper wire. Since copper is a very conductive material, and the magnets are powerful enough, the magnetic field created by the vibrating strings is converted into an electrical signal in the pickup and sent through wires through the volume and tone pots of the instrument. There, the signal can be altered depending on the player's needs and wants.
Once the signal is past the volume and tone pots, the guitar is done making the sound. The signal is then transferred via shilded cable to an amplifier of some sort. The amplifier takes the raw signal from the guitar and makes it louder, most of the time, shaping the sound a bit further in the process.
