Marching band evolved from military bands and parade bands. Everyone moved, and all instruments were carried. As recently as the early 1980s, bands and drum corps still carried bells, xylophones, and even timpani (1 per player) on and off the field. As field pageantry became more theatrical and moved beyond traditional Sousa march music, composers and arrangers liked the idea of using more orchestral percussion instruments. Thankfully, they started parking the large instruments on the front sideline, to contribute to the musical score, but not necessarily be a big part of the visual production… like a ‘pit orchestra’ in music theatre. These front-sideline percussion instruments and players are often referred to as the ‘pit,’ like the ‘orchestra pit.’ We see several timpani (‘kettle drums’), grand marimbas, vibraphones, tubular chimes, giant concert bass drums, gongs, and much more in a modern band.
Another thing you might notice: Many bands also use electronics and amplification in the front ensemble. There are many reasons for this, including using microphones to amplify wind-instrument soloists, adding synthesizer and sampler sounds to the show, and amplifying the pit instruments. Hamilton has used electronics and amplification in the past, but we don’t always need to.