Binaural Listening and Interaural Noise Correlation
William J. Trittipoe, Irwin W. Pollack · The Journal of the Acoustical Society of America · 1959
Six initially naive listeners attempted to detect the absence or presence of a 180° change in phase of a white noise voltage at one of two matched binaural earphones. Over the range of conditions examined, duration (range: 10 to 1000 msec) and frequency band (low pass to 200 cps and high pass to 4000 cps) modified phase detection performance substantially less than noise level (30 to 90 db SPL). The role of interaural noise correlation was examined with 6–8 experienced listeners. Following the procedure of Licklider, a common noise source (C) was mixed individually with two independent noise sources (A and B) and presented to separate earphones. The largest interaural noise correlation discriminable from perfect correlation was determined by presenting (C+B) to one earphone, and either (C+A) or (C+B) to the other earphone. The 75% recognition differential was obtained with a C/(A or B) ratio of +12.0 db, which is equivalent to an interaural correlation of about 0.97. The minimal interaural noise correlation for detection of a 180° change in phase was determined by presenting (C+A) to one earphone, and (C+B) was presented either in phase or 180° out of phase to the other earphone. The 75% recognition differential was obtained with a C/(A or B) ratio of −1.0 db, which is equivalent to an interaural correlation of about 0.66.