The tuba is the largest and lowest-pitched brass instrument. It was invented by Wilhelm Friedrich Wieprecht and Johann Gottfried Moritz to replace the 'ophicleide,' a loud but clumsy brass instrument used in early 19th-century bands. The tuba uses a large cup-shaped mouthpiece and valves to change the length of the tubing, thereby changing the pitch. It provides the harmonic foundation for both orchestras and brass bands. A unique variant is the 'Sousaphone,' invented by J.W. Pepper for John Philip Sousa’s marching band. The Sousaphone is designed to wrap around the player's body and has a forward-facing bell, making it easier to carry while marching. Despite its size, the tuba is surprisingly agile; modern virtuosos play complex solos that were once thought impossible for such a massive instrument, showing its range beyond simple 'oom-pah' rhythms.