2022 NHCA Annual Virtual Conference

Backup alarms are often mandatory on heavy vehicles. This presentation focuses on the benefits of the broadband versus the tonal alarm for sound localization, and the effects of both hearing loss and level-dependent HPDs. When using a short signal duration, percent correct identification of the source (8AFC) was about twice higher for the broadband alarm than for the tonal alarm in normal-hearing individuals not wearing HPDs. Hearing protection, particularly earmuffs, had a deleterious effect on sound localization and level-dependent HPDs did not restore performance to unprotected levels. Using a longer signal, sound localization was measured without HPDs, and with level-dependent earmuffs and earplugs. For both alarms, accuracy in normal-hearing individuals was highest without hearing protection and only slightly affected by HPDs, except when earmuffs were used in their passive mode. While a similar trend was noted in the hearing-impaired group, performance in most listening conditions was lower than in the normally-hearing group. Results show that the broadband alarm remains the best choice for a backup alarm when sound localization is critical, but care must be exercised in the selection of HPDs. (Co-Authors: Christian Giguère, Véronique Vaillancourt, Mohamad Ghaith, Celina Khouri, Philippe Auclair, Rachel Saraya, Hugues Nélisse)