Localization of Acoustic Signals Used in Sound Emitters at Pedestrian Crosswalks

Abstract

This study aimed at determining an optimal acoustic signal, which could be used in sound emitters at blind and visually impaired enabled pedestrian crosswalks. Two signals were identi ed from among groups of tested signals on the basis of psychoacoustic tests. These two signals met the following standard requirements: TR signal a signal with a triangular temporal envelope and a sinusoidal carrier and RC signal a signal with a rectangular temporal envelope and a rectangular carrier, both with a basic frequency of 880 Hz, repeated periodically with a frequency of 5 Hz. The ability to localize was tested by a modi ed method of angle of directional hearing acuity in which the two alternative forced choice adaptation procedure was used. The test signals were emitted against the background of tra c noise and the ratio of the useful signal (65 dB SPL) to noise (75 dB SPL) was (−10 dB). The tests were conducted on 8 subjects with normal hearing (5 women and 3 men), aged 22 37 years. Following statistical analysis it was found that: individual subjects' responses di ered considerably with respect to angle of direction hearing acuity values, localization is most di cult at the angles of 90◦ and 270◦, worse localization for trams noise were stated, RC signals are better localized than TR signals.