What type of sound does a director of a theatrical prodyction not want?

Unrelated offstage noise from actors.

Explanation:

The audience sould not be able to hear the actors that are offstage moving about, warming up, changing costumes, etc. These offstage noises can be distracting and ruin the illusion of the play's world, breaking the fourth wall. Additionally, these noises might also distract the actors who are performing on stage.