Question

What is the primary function of unpitched percussion instruments?

Answer 1

Maybe just to have a different sound? I'm not really sure.

Answer 2

Unpitched percussion is typically used to maintain a rhythm or to provide accents, and its sounds are unrelated to the melody and harmony of the music. Within the orchestra unpitched percussion is termed auxiliary percussion, and this subsection of the percussion section includes all unpitched instruments of the orchestra however they are played.