Spatially-modulated Auditory Alerts

The technique of spatial modulating (“jittering”) an existing or newly created auditory alert along a virtual trajectory to improve its detection in a noisy environment is described. Threshold data from 14 participants were gathered as a function of spatial modulation rate (0, 1.6 and 3.3 Hz) of an avionics “wind sheer” alert (two successive 300 ms square waves) against a steady state background noise (Boeing 737-300 flight deck ambient sound). The 70.7% absolute detection threshold for the spatially jittered alert was on average 7.8 dB lower compared an alert that is not spatially jittered, with noise and signal both presented over headphones using virtual simulation techniques. With the addition of supra-aural headphones to partially attenuate loudspeaker background noise, the threshold for the spatially-jittered alert was 13.4 dB lower than a nonjittered alert. Non-head tracked virtual simulation of the background noise over headphones yielded jittered alert thresholds within 1.5 dB of loudspeaker simulation.