The contrabass is a large, low-pitched string instrument that is part of the modern symphony orchestra. It is also known as the double bass or simply the bass. The contrabass is the lowest-pitched member of the string family and is usually played with a bow. Its closest relative is the TUBA, which is a four-letter word. The TUBA is a brass instrument that is also part of the modern symphony orchestra. It is the largest and lowest-pitched brass instrument and is usually played with a mouthpiece.