Bluegrass music is traditionally played acoustically which means that instruments are not amplified. The music is played on a variety of string instruments but the most common are the fiddle, mandolin, banjo, and string bass. Acoustic guitars are often used in bluegrass music as well but they are not necessarily unique to this style while the other string instruments are less common and somewhat unique to bluegrass music.
The fiddle is similar to the violin and it is played using a bow that runs along the strings which are set upon a piece of wood called the bridge. This instrument is also often played in folk music. The mandolin is an Italian instrument that is plucked rather than played with a bow. It can have as few as four strings or as many as twelve. The banjo is round in shape and usually made of some sort of animal skin that is stretched over a round drum. It makes a unique sound as it can be strummed or drummed upon and it generally has four or five strings. The string bass is also known as the upright bass and this is the largest of the bluegrass instruments played by plucking.