Certification of an auditorium entails specific acoustic and other technical requirements ; architectural requirements include a floating floor , baffled and acoustically treated walls , non-parallel walls ( to reduce standing waves ) , a perforated screen ( to allow center channel continuity ) , and NC30 rating for background noise ( `` ensures noise from air conditioning units and projection equipment does not mask the subtle effects in a movie 's soundtrack . '' )
Certification of an auditorium entails specific acoustic and other technical requirements ; architectural requirements include a floating floor , baffled and acoustically treated walls , no parallel walls ( to reduce standing waves ) , a perforated screen ( to allow center channel continuity ) , and NC30 rating for background noise .