The double bass is the largest and lowest-pitched bowed string instrument.
To play it, the musician stands up or sits on a high stool, and puts the instrument like the cello, vertically. Besides, the double bass shape is slightly different, with a flat back and different tuning.
The early basses varied in the number of strings, three to six, and also the shape.
Curiously, during the colonial period, it also got a different name from that we know today, from portuguese and Brazilian: it was called "big rabecão". Nowadays, the double bass may vary the design, being bigger or smaller, depending on the player preference and style to play. Normally, the ones used in the orchestra are bigger than the ones used in solo plays, and have four strings.
Watch the video and learn more about the double bass.