The head shadows and reflects sound to create level differences between the ears.

Evidence

The interaural level difference, ILD, is another major binaural cue. It is commonly known as the level difference between the ear canal signals. Plane waves produce an ILD due to the scattering – the shadowing and reflection – of sound waves by the head. When a sound wave from a distant source arrives at the head, the pressure level increases due to reflection at the ipsilateral ear and the pressure level decreases at the contralateral ear, as shown in the centre panel in Figure 12.5. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1433

Categorization

• DEFINE: Defines ILD as a scattering-based binaural localization cue.
• XREF: connects to: Head shadow attenuates sound arriving at the far ear unless the source is centered — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1454; Head scattering creates level differences between the two ears’ received signals.; Head shadow gives one ear a better signal-to-noise ratio in typical listening — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1544 (+4 more)

Broader Connections

• Head scattering creates level differences between the two ears’ received signals. #corroborates (0.95)
• Head shadow attenuates sound arriving at the far ear unless the source is centered #expands (0.92) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1454
• Head shadowing gives roughly 6 dB interaural amplitude difference near 1.85 kHz #expands (0.85)
• Head shadow gives one ear a better signal-to-noise ratio in typical listening #expands (0.80) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1544
• Sound’s wavelength determines whether it reflects off the head or diffracts around it #expands (0.80) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1445
• Acoustic head shadow creates a better ear with higher SNR in everyday listening #expands (0.78)
• Exaggerated interaural level differences signal that a sound source is near #expands (0.72) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1529