A fretless bass with flatwound strings; note the markers inlaid into the side of the fingerboard, to aid the performer in finding the correct pitch.
Another design consideration for the bass is whether to use frets on the fingerboard. On a fretted bass, the frets divide the fingerboard into semitone divisions (as on a guitar). The original Fender basses had 20 frets, but modern basses may have 24 or more. Fretless basses have a distinct sound, because the absence of frets means that the string must be pressed down directly onto the wood of the fingerboard as with the double bass. The string buzzes against the wood and is somewhat muted because the sounding portion of the string is in direct contact with the flesh of the player's finger. The fretless bass allows players to use the expressive devices of glissando, vibrato and microtonal intonations such as quarter tones and just intonation.
Jazz fusion bassist Jaco Pastorius was known for his expressive fretless bass playing.
Some bassists use both fretted and fretless basses in performances, according to the type of material they are performing, as with Pino Palladino, whose performance on the fretless bass during the 1980s made him a highly desirable session player backing high profile musicians that included Eric Clapton and David Gilmour. However, the late 1990s showed a shift toward fretted basses as well, as he branched out into a wide variety of genres. While fretless basses are often associated with jazz and jazz fusion, bassists from other genres use fretless basses, such as metal bassist Steve DiGiorgio and Colin Edwin of modern/progressive rock band Porcupine Tree.
The first fretless bass guitar was made by Bill Wyman in 1961 when he converted an inexpensive Japanese fretted bass by removing the frets.[18][19] The first production fretless bass was the Ampeg AUB-1 introduced in 1966, and Fender introduced a fretless Precision Bass in 1970. In the early 1970s, fusion-jazz bassist Jaco Pastorius created his own fretless bass by removing the frets[20] from a Fender Jazz Bass, filling the holes with wood putty, and coating the fretboard with epoxy resin.[21] Some fretless basses have "fret line" markers inlaid in the fingerboard as a guide, while others only use guide marks on the side of the neck.
Tapewound (double bass type) and flatwound strings are sometimes used with the fretless bass so the metal string windings don't wear down the fingerboard. Some fretless basses have epoxy coated fingerboards to increase the fingerboard' durability, enhance sustain, and give a brighter tone. Although most fretless basses have four strings, five-string and six-string fretless basses are also available. Fretless basses with more than six strings are also available as "boutique" or custom-made instruments.
