Summarizing The Brass Facts Some horns are made of brass. Brass is a shiny, gold- colored metal. A trumpet is a kind of horn. It is made of brass. There are many other kinds of horns. The trombone is a horn. A tuba is a horn. They are also made out of brass. To play any horn you blow in one end. Sound comes out of the other end. You also press keys. You press the keys to change the sound.