Name: 8 String Guitar.
Type: Chordophones > Lutes > Guitars > Extended Range.
Hornbostel-Sachs No#: 321.321.5/6
Courses: 8 Single Strings.
Country: USA, Many.
Region: North America.
Description: An eight string guitar has two or more strings then the usual six string guitar or one more then the 7 string guitar. Eight string guitars are available although less common then their six or seven string guitar counterparts. They are played by classical, jazz and metal guitarists. The eight string guitar allows for a wider tonal range and or non-standard tunings.
Construction: The eight string guitar follows the same approach to its six string counter part. The primary difference is that due to the amount of strings added to the guitar. The neck needed to be thicker then the conventional six-string guitar. Frets are installed in a chromatic fashion. The main design issue faced with an eight-string guitar is tuning stability with the lower strings. This is due to the neck being constructed too short, bridge problems such as improper intonation, uneven spacing for floating bridges, or the use of wrong string gauges.
Other problems associated with tuning stability rely on proper set up of the guitar. Some extended range eight string guitars feature a multi-scale design where the bass strings will be longer then the treble strings. This is what is called a “fanned fret” design. Fretting the eight string guitar in a “fanned” manner assists with the intonation of the lower strings, it improves the string tension, and the balance across the strings improving the harmonic overtones and harmonic overtone series.
Citations: Bibliography: Websites