Impact of aircraft sound quality combined with the repetition of aircraft flyovers on annoyance as perceived activity disturbance in a laboratory context

This study focuses on perceived activity disturbance evaluated by participants who are subjected to the repetition noise of current aircraft and modified aircraft in regard to tonal quality. A previous study devoted to the sound quality of aircraft noise revealed that one of the most important perceptive features is the emergence of Doppler shifted tones. Six 20-min sound sequences were created combining two variables: number of aircraft (N1 with six aircraft and N2 with 10 aircraft plus one sequence without aircraft N0) and tonality (sequences with current aircraft, sequences with +5 dB-amplified tonality and sequences with −5 dB-attenuated tonality). For all sequences, the equivalent sound level and the peak level of the loudest event are constant, except for the sequence without aircraft. Sixty-three subjects, attending two different sequences in one session, rated on a category scale the level of activity disturbance due to the noise environment when carrying out memory and concentration tasks. The order of presentation was controlled as an additional variable in the variance analyses. The perceived activity disturbance is significantly influenced by the equivalent sound level. The influence of the number of aircraft flyovers is statistically significant at the 5% level. High tonal components have no effect on perceived disturbance. Memory and concentration performances, measured by number of incorrect or correct answers, are influenced only by the order of presentation, revealing the importance of the learning effect. Reaction time, which is influenced by the equivalent sound level, seems better adapted for measuring the effect of noise on task achievement. These results are discussed in regard to related research.