Editing Double bass (section)

===Construction===
The double bass is closest in construction to violins, but has some notable similarities to the [[violone]], the largest and lowest-pitched member of the viol family. Unlike the violone, however, the fingerboard of the double bass is [[fret|unfretted]], and the double bass has fewer strings (the violone, like most viols, generally had six strings, although some specimens had five or four). The fingerboard is made of [[ebony]] on high-quality instruments; on less expensive student instruments, other woods may be used and then painted or stained black (a process called "ebonizing"). The fingerboard is radiused using a curve, for the same reason that the bridge is curved: if the fingerboard and bridge were to be flat, then a bassist would not be able to bow the inner two strings individually. By using a curved bridge and a curved fingerboard, the bassist can align the bow with any of the four strings and play them individually. Unlike the violin and viola, but like the cello, the bass fingerboard is somewhat flattened out underneath the E string (the C string on cello), this is commonly known as a [[Bernhard Romberg#:~:text=Romberg was born in Dinklage.&text=He also invented what is,children to play the instrument.|Romberg]] bevel. The vast majority of fingerboards cannot be adjusted by the performer; any adjustments must be made by a luthier. A very small number of expensive basses for professionals have adjustable fingerboards, in which a screw mechanism can be used to raise or lower the fingerboard height.

An important distinction between the double bass and other members of the violin family is the construction of the [[pegbox]] and the tuning mechanism. While the violin, [[viola]], and cello all use friction [[tuning peg|pegs]] for tuning adjustments (tightening and loosening the string tension to raise or lower the string's pitch), the double bass has metal [[machine head]]s and gears. One of the challenges with tuning pegs is that the friction between the wood peg and the peg hole may become insufficient to hold the peg in place, particularly if the peg hole become worn and enlarged. The key on the tuning machine of a double bass turns a metal ''worm'', which drives a [[worm gear]] that winds the string. Turning the key in one direction tightens the string (thus raising its pitch); turning the key the opposite direction reduces the tension on the string (thus lowering its pitch). While this development makes fine tuners on the tailpiece (important for violin, viola and cello players, as their instruments use friction pegs for major pitch adjustments) unnecessary, a very small number of bassists use them nevertheless. One rationale for using fine tuners on bass is that for instruments with [[#C extension|the low C extension]], the pulley system for the long string may not effectively transfer turns of the key into changes of string tension/pitch. At the base of the double bass is a metal rod with a spiked or rubberized end called the endpin, which rests on the floor. This [[endpin]] is generally thicker and more robust than that of a cello, because of the greater mass of the instrument.

The materials most often used in double bass construction for fully carved basses (the type used by professional orchestra bassists and soloists) are [[maple]] (back, neck, ribs), [[spruce]] (top), and ebony (fingerboard, tailpiece). The tailpiece may be made from other types of wood or non-wood materials. Less expensive basses are typically constructed with [[laminate]]d ([[plywood]]) tops, backs, and ribs, or are hybrid models produced with laminated backs and sides and carved solid wood tops. Some 2010-era lower- to mid-priced basses are made of [[willow]], student models constructed of [[Fiberglass]] were produced in the mid-20th century, and some (typically fairly expensive) basses have been constructed of [[carbon fiber]].
[[File:Efe cb.jpg|thumb|left|upright=0.9|This photo shows the thick soundpost on a double bass (circled in green).]]
Laminated (plywood) basses, which are widely used in music schools, [[youth orchestra]]s, and in popular and folk music settings (including rockabilly, psychobilly, blues, etc.), are very resistant to humidity and heat, as well to the physical abuse they are apt to encounter in a school environment (or, for blues and folk musicians, to the hazards of touring and performing in bars). Another option is the hybrid body bass, which has a laminated back and a carved or solid wood top. It is less costly and somewhat less fragile (at least regarding its back) than a fully carved bass.

The [[soundpost]] and [[bass bar]] are components of the internal construction. All the parts of a double bass are glued together, except the soundpost, bridge, and tailpiece, which are held in place by string tension (although the soundpost usually remains in place when the instrument's strings are loosened or removed, as long as the bass is kept on its back. Some luthiers recommend changing only one string at a time to reduce the risk of the soundpost falling). If the soundpost falls, a luthier is needed to put the soundpost back into position, as this must be done with tools inserted into the f-holes; moreover, the exact placement of the soundpost under the bridge is essential for the instrument to sound its best. Basic bridges are carved from a single piece of wood, which is customized to match the shape of the top of each instrument. The least expensive bridges on student instruments may be customized just by sanding the feet to match the shape of the instrument's top. A bridge on a professional bassist's instrument may be ornately carved by a luthier.

Professional bassists are more likely to have adjustable bridges, which have a metal screw mechanism. This enables the bassist to raise or lower the height of the strings to accommodate changing humidity or temperature conditions.<ref>{{Cite web |title=How bridge adjusters work on double bass |url=https://doublebasshq.com/gear_posts/how-bridge-adjusters-work-on-double-bass/ |access-date=2024-09-01 |website=Double Bass HQ |language=en-US}}</ref>  The metal tuning machines are attached to the sides of the pegbox with metal screws. While tuning mechanisms generally differ from the higher-pitched orchestral stringed instruments, some basses have non-functional, ornamental [[tuning peg]]s projecting from the side of the pegbox, in imitation of the tuning pegs on a cello or violin.<ref>{{Cite web |title=How bridge adjusters work on double bass |url=https://doublebasshq.com/gear_posts/how-bridge-adjusters-work-on-double-bass/ |access-date=2024-07-13 |website=Double Bass HQ |language=en-US}}</ref>

====Travel instruments====
Several manufacturers make travel instruments, which are double basses that have features which reduce the size of the instrument so that the instrument will meet airline travel requirements. Travel basses are designed for touring musicians. One type of travel bass has a much smaller body than normal, while still retaining all of the features needed for playing. While these smaller-body instruments appear similar to [[electric upright bass]]es, the difference is that small-body travel basses still have a fairly large hollow acoustic sound chamber, while many EUBs are solid body, or only have a small hollow chamber. A second type of travel bass has a hinged or removable neck and a regular sized body. The hinged or removable neck makes the instrument smaller when it is packed for transportation.