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
Twelve-string guitar an octave lower) to achieve a very rich, complex sound. The greater number of strings offers almost endless possibilities. Nashville Tuning refers to a way of simulating a 12-string guitar sound, using two six-string guitars playing in unison. This is achieved by replacing the lower four courses on one six-string with the higher octave strings for those four courses from a 12-string set, and tuning these four strings an octave higher than normal tuning for those courses on a six-string. Double-tracking this guitar with the standard-tuned six-string is commonly used in recording studios to achieve a "cleaner" 12-string effect. The