Influence of the number and sound level of noise events and task engagement on perceived loudness and annoyance

It is not clear how the distribution of noise sound-energy over time influences people. We compared perceived loudness, annoyance and ability to perform a cognitive task in people exposed to recordings of aircraft noise, presented either as a single 15-second overflight at 80 dB LeqA15seconds or four 15-second overflights at 60 dB LeqA15seconds. Levels were chosen on the basis that an increase of 10 dB doubles the perceived loudness, thus four stimuli at 60 dB might be expected to seem as loud as a single stimulus at 80 dB. Participants performed an engaging mental arithmetic task during half the noise presentations and rated their perception of loudness and annoyance to every presentation. Overall, the single 80-dB-flight stimulus was perceived as louder and more annoying than the four 60-dB flights. While doing the task, the four 60-dB flights were perceived as louder and more annoying than without the task, whereas the single 80-dB stimulus was less loud and no more annoying than without the task. Noise did not influence task performance. Future research may explore systematically the relationship between the number and sound level of overflights and the reactions they induce.