Interaural Phase and the Absolute Threshold for Tone

The present study agrees with earlier ones that the binaural absolute threshold is about 3 dB lower than the monaural. It also finds that reversing the interaural phase of the signal lowers the threshold still further. The findings are shown to indicate the likelihood that so-called absolute thresholds are really masked thresholds, with the masking noise present internally and exhibiting a small positive correlation. The close relation of our results to the earlier work of Hirsh on binaural masking phenomena is discussed.