| − | Guitars can also be classified according to their range capabilities. Electric guitars have a 4-octave range, while bass guitars have a 3-octave range which is one-octave lower than the electric guitar's range. The range of these guitars may be altered by using guitars with twelve strings. This is commonly known as a doubled six-string guitar, however the second set of strings are tuned to an octave higher than the original strings. Therefore, this would add another octave to the guitar's upper range. | + | Guitars can also be classified according to their range capabilities. Electric guitars have a 4-octave range, while bass guitars have a 3-octave range which is one-octave lower than the electric guitar's range. There also exist seven and eight (although the latter are not common) stringed guitars which usually extend the bass range. |