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
Scale length (string instruments) electric basses built in the 1930s by fitting an otherwise normal double bass with electric pickups, and so had a scale length of about 43" (109 cm). In 1951 the Fender Precision Bass shortened this to 34" (86 cm). This is still often regarded as the standard length for a bass guitar. On a modern bass guitar, 30" (76 cm) or less is considered "short" scale, "standard" (also called "long") scale is 34" (86 cm) for a 4-string and 35" (89 cm) for a B-E-A-D-G 5-string, and "extra-long" scale basses of 36" (91 cm) also exist. Quite an uncommon scale