Psychoacoustic Evaluation of an Optimized Low-Noise Drone Propeller Design

Abstract

The noise emissions of an optimized low-noise drone propeller design were measured experimentally using a polar array consisting of fifteen microphones within a circular arc covering 105 degrees. The experiments were conducted in the anechoic chamber at the Faculty of Aerospace Engineering at the Technion - Israel Institute of Technology. A comparison between the optimized low-noise drone propeller design and the baseline case (a commercial off-the-shelf APC 14 x5.5 propeller) was performed using conventional sound metrics (e.g. equivalent A-weighted sound pressure level or perceived noise level), as well as state-of-the-art psychoacoustic sound quality metrics (loudness, sharpness, tonality, roughness, and fluctuation strength). These sound quality metrics (SQMs) were also combined into a global psychoacoustic annoyance metric to assess the predicted noise annoyance a human observer would experience. Despite increasing noise levels at the lower frequencies, the optimized configuration presents consistently lower noise emissions in the directivity angles considered for all the sound metrics employed. These results encourage further research into the perceptioninfluenced design of drone propellers by focusing on psychoacoustic metrics that capture human hearing more accurately than conventional sound metrics typically used in certification.