Figure 8

Stimuli and experimental design. Amplitude spectra of the auditory stimuli measured at the silicon earpiece fit to the subject's ear. (A) Spectrum of the masker (comb-filtered noise; CFN). The distance between neighboring centers of pass-band sections is half an octave in the frequency range between 0.5 and 2.8 kHz. (B) Spectrum of the pass-band stimulus (PB) composed of five spectral components corresponding to the center frequencies of the pass-band sections of the CFN. Due to the 40 Hz amplitude modulation, each component shows spectral peaks at its carrier frequency and at two sideband frequencies 40 Hz below and above. (C) Spectrum of the complex sound stimulus characterized by frequency components corresponding to the stop-band sections (SB) of the comb-filtered noise. All acoustical spectra reflect the low pass characteristic of the sound transmission system. Masking conditions. (D) Contra-lateral masking condition: TS and CFN were presented to different ears. (E) Ipsi-lateral masking condition: TS and CFN were presented to the same ear. (F) Control condition: Only the TS was presented to one ear, no masker was presented. Design of the experiment. (G) One session consisted of four blocks with three sub-blocks. Each sub-block consisted of either the contra-lateral, the ipsi-lateral, or the control condition. Within one session, the TS was presented only to the right or to the left ear.