Increasing Detectability and Reducing Annoyance of Alarm Design Using Acoustic Structures of Musical Instruments

Abstract

Auditory alarms play a crucial role in safety critical contexts such as medical devices. Traditionally, alarms utilize sustained harmonics that lack the temporal dynamics found in complex sounds which are not easily detectable unless played at a high volume, leading to increased annoyance (Foley et al., 2023). Here we explore how insights from musical instruments can be used to improve auditory alarms by balancing annoyance and detectability. We synthesized tones mimicking key properties of a musical triangle—an instrument known to “cut through” large ensembles without being annoying. We then tested two classes of stimuli, (1) a triangle inspired and (2) a standard alarm tone. The triangle stimuli feature twelve of the most prominent frequencies, amplitudes, and temporal variation from a recording of a triangle, including a percussive amplitude envelope. Standard tone follows conventional approaches with the fundamental at 261 Hz and four additional harmonics, shaped with a flat amplitude envelope. To compare the triangle to the standard tone, we conducted an in-person detection and an online annoyance rating experiment. For detection, participants indicated if the auditory stimulus is heard when presented a range of signal-to-noise (SNR) ratios. For annoyance, participants rated which tone is perceived as more annoying across SNRs in a two-alternative forced choice task. As expected, reductions in SNR led to reductions in annoyance X2(5, N = 4488) = 478.01, p .05. This suggests that features of musical instruments such as the triangle could provide useful insight for reducing alarm annoyance while preserving detectability.