Interaural time difference
From Wikipedia, the free encyclopedia
The interaural time difference (often contracted to ITD) is the differences in arrival time of a sound at two sensors. Normally used biologically, it is the difference in arrival time of a sound between two ears. Occasionally used in an engineering sense, it is the difference in arrival time between two microphones (where it is more often called the time difference of arrival (often contracted to TDOA). It provides a cue to the azimuthal direction of the source of the sound: sounds from a direction orthogonal to the line joining the ears (i.e. directly ahead or behind, or indeed above) have zero ITD. The ITD does not, however provide any information about the elevation of the sound source. ITD appears to be used in conjunction with the Interaural Intensity Difference (IID, sometimes called the Interaural Level Difference, or ILD) by animals to locate sound sources both azimuthally and in elevation. It is believed that the Medial Superior Olive (MSO) (part of the Superior olivary nucleus) in the brainstem plays an important part in processing interaural time differences.
