Exact noise levels for the AR50 have not been determined. Exact specifications would be very difficult to create, as noise levels depend on the environment (what type of material it is mounted to, how far away it is mounted, etc.) Levels also depend on what motors are being moved and in what sequence. When no motors are moving, the luminaire is silent.
The AR50 is called a "Virtually Silent" luminaire, a term inherited from Vari-Lite*(tm).
Note: that some customers have sucessfully used vibration isolation pads to reduce noise transmited through the mounting surface.