a capella
"a cappella," which specifically means singing without instrumental accompaniment.
None. A Capella is defined as singing without instrumental sound.
It means without accompaniment (instruments). In other words all vocals, no other music.
Acapella singing is a manner of singing without any musical accompaniment. Literally meaning 'in the manner of the church' in Italian, this type of singing can be hauntingly beautiful and is best known as sung by Gospel singers and Barber Shop Groups It's style crosses all genres of music.
A capella A cappela