In 'The Voice' (US), the auditions where coaches cannot initially see singers are called blind auditions.
During this stage, the coaches sit in chairs facing away from the performer. They judge the singer primarily by vocal performance, rather than appearance, age, or stage presentation. If a coach wants the singer, pressing a button turns the chair around.
The format was designed to distinguish 'The Voice' from talent shows that begin with face-to-face auditions. More than one coach can turn, allowing the singer to choose a team. If only one coach turns, that coach automatically receives the contestant.
Blind auditions also appear in many international versions of 'The Voice'. They are separate from later Battle Rounds, Knockouts, and live shows, where coaches and audiences can see the performers.