Guitar Frets are laid out to accomplish an equal tempered division of the octave. Each set of twelve frets represents an octave. The twelfth fret divides the scale length exactly into two halves, and the 24th fret position divides one of those halves in half again. The ratio of the spacing of two consecutive frets is formula_1 (twelfth root of two). In practice, luthiers determine fret positions using the constant 17.817—an approximation to 1/(1-1/formula_1). If the nth fret is a distance x from the bridge, then the distance from the (n+1)th fret to the bridge is x-(x/17.817). Frets are available in
Eight-string guitar 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. Extended range eight string guitars sometimes will have a multi-scale design where the bass strings will be longer than the treble strings(fanned fret design). This helps with proper intonation of the lower strings, improves string tension balance across the strings, improves harmonic overtones, overtone series, and improves inharmonicity. (See also inharmonicity in pianos). The bass strings on an 8 string typically require the saddle to be