More commonly known as the pit. The part of a drum corps or marching band that stands in front of the field and do not march. The Front ensemble can include mallet instruments(marimba, xylophone, vibraphone, etc.), guitar, bass guitar, keyboard/synthesizer, drum set, and auxiliary, among many things. The pit is the forgotten part of most drumlines, as most people only include the battery(snares, tenors, bass drums) in the drumline. Usually very nice people who are criticized excessively by the rest of the corps because they don't march.
person 1: Look at the Front Ensemble.
Person 2: Yeah, their mallet line is incredible!
Trumpet Player: Dude, the FrontEnsemble is so lucky they don't have to march. They are so lazy.
Clarinet player: Yeah but the pit has to push all that heavy equipment to and from the field all the time.