Author(s): Taghipour Armin, Pieren Reto, Schlatter Felix, Schäffer Beat
Noise emitted by different types of small aircraft exhibits disparate acoustic characteristics. Helicopters often show typical pulsating noise, while the noise from propeller-driven aircraft contains strong tonal components. Annoyance reactions to these aircraft might therefore differ at comparable sound pressure levels. Knowledge of these potential annoyance differences, however, is still scarce. The objective of this study therefore was to investigate and compare the annoyance reactions to noise of helicopters and propeller-driven aircraft under controlled laboratory listening conditions. For the listening tests, 46 aircraft flyovers were auralized that covered different types of helicopters and propeller-driven aircraft, procedures (starts and landings), and propagation distances. The stimuli originated from recordings close to an airfield runway. Parts of the original recordings were modified by applying propagation filtering to simulate larger receiver distances for which no recordings were available. The stimuli were subsequently rendered in a 3D sound reproduction system in a listening test facility with 15 loudspeakers and two subwoofers. The sound exposure levels of the stimuli ranged from 64 and 85 dBA for stimulus durations of 24 s. 56 self-reported normal-hearing subjects participated in the listening test. They rated their short-term annoyance reactions to the (acoustical) flyover events on the ICBEN 11-point numerical scale, according to ISO/TS 15666:2003. This paper presents the acoustical stimuli and their 3D reproduction rendering, the setup of the experiment, and the most important results of the listening tests.
Name: Dr Armin Taghipour