Not a rough pounding, but a rather polite rap of knuckles.

He took a deep breath, gave the door a polite rap.

A polite rap on the door.

Slightly more than an hour later, Kloo gave a polite rap at the Talents' ready room door before she slipped quickly inside, a grin plastered on her face, as she flattened herself against the wall.

There was a polite rap on the door and when Paulin answered, Irene poked her head in.

There was a polite rap on the door, and Tynian entered with the Domi,Kring.

Timed almost to Elder's final statement, a polite rap sounded at the door.

A polite rap on the door interrupted her.