. . . . . The double bass is a musical instrument, the largest and lowest-tuned member of the family of string instruments,The double bass is a musical instrument, the largest and lowest-tuned member of the family of string instruments It resembles the other members of the family, but is much larger and has slight differences in shape. Other names for the instrument (especially when used in folk, bluegrass, and jazz music) include String bass, acoustic bass, bass violin,doghouse bass, dog-house, bull fiddle, and upright bass.
The player stands or sits and holds the instrument upright, slightly tilted
toward them. When standing, the top of the instrument (the head) is approximately
at the same height as the players head. At the base of the double bass is a
'spike' or 'foot'which rests on the floor.
Sound is produced by bowing or plucking the strings.
The Cello (abbreviated
from Italian violoncello) is a stringed instrument. Unlike the violin, the cello
is 
much
larger, and is played in an upright position between the legs of the seated
musician, with the player drawing their bow horizontally across the strings.
The cello plays notes on the bass clef, and has 4 strings tuned in fifths: C (the lowest), G, D and A (below middle C) - these are tuned exactly one octave below the viola.
