Bands are essentially made up of wind and percussion instruments, but symphonic bands often use other types of instruments in addition to these, such as the lowest instruments of the string family.
cello
The cello belongs to string instruments family. Usually played with a bow and placed vertically between the legs, it has four strings tuned in fifths, first string - A; second string - D; third string - G, and fourth string - C. This instrument belongs to the subfamily of violins, which includes orchestral instruments with four strings tuned in fifths.
double bass
It is the largest instrument in the string family and, therefore, produces the lowest-pitched sounds. It usually has four strings, but there are double basses that have five. The double bass stands on a small metal spike that rests on the floor, and the double bass player can play standing up or leaning on a high stool.
Bass/electric bass
The bass or electric bass can also be considered an 'intruder' in the string family. It has four strings with the same tuning as the double bass, so it can also be called electric double bass. Although there are several models with five and six strings, the traditional electric bass uses the four strings corresponding to the octave below the four lowest strings of a guitar, serving in certain musical styles as the bass of this instrument, which is why it is better known precisely as 'bass'. The classification of this instrument is not consensual. According to the principle of the vibrating body, we should consider it a chordophone. However, its timbre depends on its phonocaptors - electrical components commonly known as pickups. For this reason, some people classify it as a hybrid (electroacoustic) instrument, even placing it in a subgroup of electrophones. It all depends on the point of view.