When facing a single sound-source, such as a loudspeaker, sound arrives at both ears simultaneously. ITD = 0

Both ears are also similarly influenced by the head’s acoustic ‘shadow’ . ILD = 0

When the head is turned to the left, sound arrives at the right ear (red) before the left ear (blue).  ITD > 0

Sound at the left ear (blue) may also be attenuated by the head’s ‘shadow’. ILD > 0

When the head is turned to the right, sound arrives at the left ear (blue) before the right ear (red).  ITD < 0

Sound at the right ear (red) may also be attenuated by the head’s ‘shadow’. ILD < 0