Binaural signal detection with phase-shifted and time-delayed noise maskers

Detection thresholds were measured for interaurally in-phase sinusoids added to a narrow-band dichotic noise masker which was either interaurally phase shifted (N pi So condition) or time delayed (N tau So condition). The signals were spectrally centered in the noise bands and the delay tau equaled half the signal period. Both conditions were tested at 125 and 500 Hz for noise bandwidths of 10, 25, 50, and 100 Hz. In addition, NoS pi and NoSo thresholds were obtained. In contrast to expectations based on the EC theory, no differences in detection thresholds were observed between thresholds in phase-shifted and time-shifted maskers. The results also cannot be explained on the basis of more recent binaural models. The stimuli presented here might therefore serve as a useful validation tool in the development of new binaural theories and models. (C) 1998 Acoustical Society of America.