Masked Thresholds and Predicting the Audibility of Auditory Displays: An Example for Long-Haul Trucks

Abstract

Noise is an unfortunate by-product of our modern industrial society, with effects ranging from minor annoyance, to major risk of hearing damage, to inability to hear warnings and other signals. This paper presents an extensive observational study of the methodology aimed at predicting the audibility of auditory displays and warnings. While the details of the discussion relate specifically to long-haul truck-cab environments, the procedures are generally applicable to any instance where it is necessary for an individual to hear intentional or incidental sounds. The discussion includes spectral measurements of both the background noise and signals, calculation of masked threshold per ISO 7731:1986(E), and analytical comparison of signal spectra to masked thresholds to determine signal audibility. A specific example calculating the audibility of train horns in the truck cab environment is then presented. Recommendations for improving the audibility of signals in noisy environments are also provided.

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