Orchestral brass refers to a family of musical instruments made of metal, typically including the trumpet, trombone, French horn, and tuba. These instruments are known for their powerful and bright sound, which can cut through the texture of an orchestra. They are often used to add richness and depth to orchestral music, playing both melodic and harmonic roles. In an orchestra, brass instruments are usually positioned at the back, allowing their sound to project forward. They are played by buzzing the lips into a mouthpiece, and their pitch is altered by changing the lip tension and using valves or slides. Brass sections often play fanfares and bold themes, contributing to the overall dynamic of a performance.