Final answer:
Before they became a staple in symphony orchestras, brass instruments were prominently used in military bands, leveraging their loud and powerful sound to communicate signals. The improvements in instrument mechanics during the Industrial Revolution allowed these instruments to be played more easily and to produce a superior sound.
Step-by-step explanation:
Before they were adopted by a symphony orchestra, brass instruments were commonly used for military bands. The versatility of brass instruments allowed them to be essential in various scenarios, most notably in the military. Given their power and volume, brass instruments were ideal for conveying commands and signals across vast spaces. During the Industrial Revolution in the nineteenth century, significant advancements were made in the design of musical instruments, including brass. The advent of mechanical valves and keys allowed these instruments to be played with greater ease and reliability, which helped them produce a fuller and better-tuned sound. This allowed brass instruments to transition into more formal music settings like symphony orchestras, where they have become integral.