Hey Kid's, It's a String Bass
The String Bass is the largest member of the string family. It is also known as the contrabass, upright bass, bull fiddle, bass fiddle, bass violin, or just bass. It is the largest member of the string family. In our modern orchestra it is common to see eight string basses. It plays the lowest notes of any instrument in the string family and an octave lower than the cello.
The biggest difference between the String Bass and the rest of the string family of the symphony orchestra is the way the pegbox is made. The String Bass uses machine heads with small gears to tune the strings rather than friction pegs that are used on the violin, viola, and cello.