Currently there are a number of indoor noise criteria used to quantify the level of background noise in rooms, including Noise Criteria (NC), Balanced Noise Criteria (NCB), Room Criteria (RC), Room Criteria Mark II (RC Mark II) and others. This paper reviews the pros and cons of each of these and then compares the values measured in existing classrooms in the Omaha area. The authors are in the process of subjectively comparing these various criteria to determine which method best correlates with human perception. The subjective testing methods and preliminary results are discussed.
Available at: http://works.bepress.com/lilymwang/21/