A cappella groups are musical ensembles that perform without instrumental accompaniment. They rely solely on vocal harmonies and techniques to create a rich sound. Members often imitate instruments or use vocal percussion to enhance their performances, making the music dynamic and engaging. These groups can vary in size and style, ranging from small quartets to larger choirs. A cappella is popular in various genres, including pop, jazz, and classical. Many universities have their own a cappella groups, fostering a vibrant community and encouraging creativity among singers.