Interaural time difference (ITD)

The ITD is the delay that a listener perceives between the time that a sound reaches one ear and the time that it reaches the other.

The ITD cues give information regarding the angular direction of a source source:

• if the source is directly in front or behind the listener, the sound will reach both ears at the same time and the ITD will be zero.

• a typical listener can resolve the location of a sounds in front to about $2^\circ$ and from behind to about $10^\circ$.