In addition to the other responses about orchestral music often being much longer and technically difficult, there is also the amount of time spent in rehearsal. A band will often spend a lot of time rehearsing the same set of songs and slowly expand their repertoire while an orchestra will often only get a handful of rehearsals together to practice a new piece.
Also, often times a band will actually have some sort of reference material when performing new songs. For example, many drummers, especially if they are more freelance and do studio sessions or aren’t permanently a part of the band will have charts that they use to learn all of the grooves, fills, and cues.
As for the conductor, try getting 20+ rock musicians to play together coherently and you’ll understand why it’s necessary to have someone conducting. Bands have something similar called a music director who will give cues and it isn’t uncommon for musicians that play with in-ear monitors to have a click-track going that serves as a metronome to keep the band in-time.
Latest Answers