A string bass is the largest and lowest-sounding instrument in the violin family, standing about six feet tall. You might also hear it called a double bass, upright bass, or just bass. Unlike smaller string instruments that rest under your chin, the string bass stands upright on the floor, and musicians either stand beside it or sit on a tall stool to play it.

The instrument produces deep, rich tones that form the foundation of an orchestra's sound. In jazz bands, the string bass provides the rhythm and groove that makes people want to tap their feet. Musicians play it by plucking the thick strings with their fingers (called pizzicato) or by drawing a bow across them. Jazz bassists often pluck, creating that characteristic “boom-boom-boom” walking bass sound, while classical musicians more frequently use the bow.

These heavy strings vibrate slowly, producing those low notes that you can almost feel in your chest during a concert. Because it's so large, the string bass can be challenging to transport. Some professional musicians actually travel with a special flight case that's bigger than most people!