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
Eleven-string alto guitar Strömberg. Ermanno Chiavi in Switzerland is known for his 13-string guitar built for Anders Miolin, but he builds 11-string guitar as well. Chiavi's guitar has the scale length of a normal classical guitar, 650mm, and is tuned in the same manner as classical guitar. Therefore, it is technically not an "alto" guitar. Yoshimitsu Hoshino in Japan built 11-string alto guitars with the same specification with Bolin's design in 1980s. However, he no longer makes them. Some of the guitarists who use the instrument are as follows: Eleven-string alto guitar The eleven-string alto guitar (also known as altgitarr, archguitar, or Bolin