Inter-aural attenuation with insert earphones.

The aim of the present study was to determine inter-aural attenuation (IA) values for pure tones and a broadband click obtained using an ER-3A insert earphone with a foam plug and with a customized hard acrylic earmould. Participants were 15 adults with a longstanding unilateral dead ear. IA was operationally defined as the difference between the good-ear and poorer-ear not-masked air conduction threshold. Minimum IA values for the foam earplug were 50 dB and 55 dB for pure tones and broadband click, respectively. Minimum IA values for the hard acrylic earmould were 45 dB and 50 dB for pure tones and broadband click, respectively.