A capella

In music, a cappella is singing without accompaniment by a musical instrument, or a piece intended to be performed in this way (see vocal music).

Recently popular construction of an a cappella group (especially in Japan) is one made up of Vocal, Chorus, and Bass. Voice percussion (or human beatbox) is sometimes added to enthuse the field of the live.

The vocal part is the one who sings the words of the song and be as the center of the group. When the group is going to sing at like street concert, Vocal does not only sing as hard as and as well as they can, but also sometimes does some performance for watcher and make the field exciting.

Chorus (or choirs) are normally made up of three or four groups and make music with their voices. When they make music, most of the cases they use chord to make harmony.

And Bass part, which the person sings lowest of all member basically show tempo and rhythm.

To sing a song a cappella, the two most important elements to show in front of people who watch them are tempo and harmony. If tempo is on the way track, people can follow the song and listen to it likable. And same as harmony.