Flatwound Strings refer to a type of electric bass guitar strings that have a somewhat flat surface instead of the traditionally round wire. Tonally, flat wound guitar strings produce a much darker and more mellow tone than round wound strings. They don’t have the same brightness and they lack that top end sharpness and bite. They can also reduce unwanted finger noise. Flatwound strings are often used for blues and other styles of music that require a more mellow, smooth tone.