The instrument's exact lineage is still a matter of some debate, with scholars divided on whether the bass is derived from the viol or the violin family.
The double bass is the largest stringed instrument, the lowest in pitch, and it is used in most every musical style, including classical, jazz, folk, rock, country and others. It has acquired many names over the years, "String bass" and "upright bass" are common alternative monikers, as are contrabass, stand-up bass, acoustic bass and bass violin. In certain types of folk, country and bluegrass music, slang terms for the double bass include; doghouse bass; bull fiddle; and bunkhouse bass. But, there is no difference in the instrument regardless of name.
The term "string bass" was coined to differentiate it from other bass instruments--such as the tuba and bass drum--in orchestral use. The names "upright," "stand-up" and "acoustic" bass are fairly new terms, first used in the mid-20th century to distinguish the bass from the electric bass guitar.
The modern double bass has four strings and is tuned in "fourths". From low to high, the strings are tuned to the notes E, A, D and G, which is standard tuning for a bass guitar. Most double bass players use steel-core wound strings, but the use of old-fashioned "gut" or synthetic nylon equivalents strings are popular with purists.
The bass is a standard member of the orchestra's string section, as well as the concert band, and is featured in concertos, solo, and chamber music in Western classical music. The bass is used in a range of other genres, such as jazz, 1950s-style blues and rock and roll, rockabilly, psychobilly, traditional country music, bluegrass, tango and many types of folk music.
The double bass is played:
It is not uncommon for players to use both the bow and finger-plucking methods to achieve certain sounds and playing effects. In orchestral repertoire and tango music, both arco and pizzicato are employed. In jazz, blues, and rockabilly, pizzicato is the norm.
Classical music uses the natural sound produced acoustically by the instrument, as does traditional bluegrass. In jazz, blues, reggaes, and related genres, the bass is frequently amplified.
Both playing methods were used on the song Welcome Home, and it is not amplified.
1 OUR PASTIMES, https://ourpastimes.com/interesting-facts-about-the-viola-instrument-12329724.html
2 WikiPedia, https://en.wikipedia.org/wiki/Double_bass