sousaphone Largest brass musical instrument of the tuba family. It was introduced by John Sousa to fortify the bass section of US military bands.

sousaphone. Amer. helical form of bass tuba made to circle the player's body, with a large bell turned up through 2 right angles to face forward and terminating in a flange 2′ wide. Made first in 1898 for Sousa's band, the earliest model having bell which opened directly upward. New version dates from 1908. Also used in jazz.