Which instrument is NOT part of a standard string quartet?

• A. Double Bass
• B. Violin
• C. Viola
• D. Cello

Answer: (A)

A standard string quartet is designed with four parts that balance across the instrument family: two violins, a viola, and a cello. Each player covers a distinct range, with the violins often carrying higher melodies, the viola filling the middle, and the cello providing the foundational bass line. The double bass sits much lower in pitch and is typically used in larger ensembles like orchestras, or in other settings where its fuller bass presence is desired. In the quartet, the cello already supplies the bass voice, so adding a double bass would crowd the texture and duplicate range. Therefore, the instrument not included in the standard string quartet is the double bass.