Evaluating Use of the Doppler Effect to Enhance Auditory Alerts

Abstract

Auditory alerts are an essential part of many multi-modal interaction scenarios, particularly in safety and mission critical settings, such as hospitals and transportation. A variety of strategies can be employed in the design of auditory alerts, often orienting manipulation of volume and pitch parameters. However, manipulations by applying a Doppler effect are under-investigated. A perceptual listening test is conducted (n=100) using multiple alert sounds that are subjected to a variety of volume, pitch and Doppler manipulations, with the unaltered sounds serving as a benchmark. Applying a mixed methods approach consisting of inferential statistics and thematic analysis, it is found that decreases in volume and a Doppler simulation of a sound moving away reduce importance and urgency, increase safety, are harder to detect, and are perceived as being more distant in perceptions of auditory alerts. Further, increases in volume and a Doppler simulation of a sound approaching are effective in communicating safety, whilst pitch manipulations were much less effective. Further work is required to provide wider, ecologically valid, verification of these findings, particularly as to how listener detection of Doppler and volume manipulations can be improved. KEYWORDSAuditory alerts; Doppler effect; listening test; mixed-methods; sound design. Doppler down (M D = −0.162, p < 0.001) Doppler up (M D = 0.138, p = 0.007) Volume down (M D = −0.186, p < 0.001) Volume up (M D = 0.189, p < 0.001) Urgent/Trivial Doppler down (M D = 0.355, p < 0.001) Volume down (M D = 0.379, p < 0.001) Volume up (M D = −0.132, p = 0.006) Difficult to detect/Easy to detect Doppler down (M D = −0.401, p < 0.001) Doppler up (M D = −0.140, p < 0.001) Pitch down (M D = −0.102, p = 0.001) Volume down (M D = −0.366, p < 0.001) Volume up (M D = −0.092, p = 0.003) Close/Distant Doppler down (M D = 0.552, p < 0.001) Pitch down (M D = 0.143, p = 0.004) Volume down (M D = 0.508, p < 0.001)