A comparison of source types and their impacts on acoustical metrics

Abstract

The purpose of this study is to compare acoustical measurements made with different source types in a relatively reverberant room to determine if ISO 3382 monaural acoustic parameters such as Reverberation Time (RT), Early Decay Time (EDT), and Clarity Index (C80), yield different results for natural acoustic source stimuli. The source stimuli used in the study included Maximum Length Sequences (MLS), a running train of speech, a running piece of music and a balloon pop. The scientifically calibrated method is then compared to acoustical measurements obtained from natural acoustic sources, which include anechoic recordings of voice and music played through a directional speaker in the front of the room to simulate activities that would normally take place in the room, such as a person speaking and music being played during a worship service. This analysis is performed to determine if there are differences in acoustic room parameters using natural acoustic sources. This study essentially compares the effects of different source stimuli on measured acoustic parameters. It was found that different source signals and receiver locations significantly affect the acoustic metrics derived from the acoustical measurements due to variations in frequency, level and directionality.