Because the double bass is the largest instrument in the orchestra.
The lowest string on a four string double bass is an E string. If you have a fairly rare five string double bass then the lowest fifth string is a B string.
A double bass quartet is an ensemble consisting of four double basses. A bass quintet is either an ensemble with five double basses or a regular string quartet (two violins, viola and cell) with a double bass added to the group.
The Double Bass is a string instrument. Other instruments in the orchestral family of string instruments are the violin, viola and cello.
String
The Double Bass has several different names such as the; String Bass, Upright Bass, Standup Bass or Contrabass.
Members of the orchestral string family are Violin, Viola, Cello and Double Bass.
The Double Bass or the Contrabass is the lowest member of the string family.
The double bass is called so because it is the largest and lowest-pitched instrument in the string family, providing a "double" or deeper bass sound compared to other string instruments.
the double bass has 4 strings G string D string A string and E string.
string
The double bass
the double bass (as in bass like a cello not a guitar)