Analysis of mouth click sounds used in echolocation

The aim of the presented study was to determine and compare basic signal properties of mouth clicks commonly made for the purpose of echolocation. It was possible thanks to the involvement of 30 sighted volunteers, who prepared mouth clicks' recordings according to the received instructions. The volunteers recorded three types of oral palatal tongue clicks - loudest, highest pitched and lowest pitched repeating each 10 times. All samples were automatically analyzed to calculate their main frequency and amplitude in relation to the loudest sound. The majority of frequencies from all mouth clicks were obtained in the range of 0.5–2kHz. The clicks were most consistent in frequency, but also lowest in amplitude when the volunteers were instructed to aim for a low pitch.