Head scattering creates level differences between the two ears’ received signals.

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

Category: Definitional Content

• DEFINE: Defines ILD mechanistically via head scattering — ipsilateral boost from reflection, contralateral drop from shadowing.

Related

• The head shadows and reflects sound to create level differences between the ears. (similarity 0.93)
• Head shading creates interaural level differences used for sound localization (similarity 0.86)
• Head shadowing gives roughly 6 dB interaural amplitude difference near 1.85 kHz (similarity 0.84)
• Interaural level differences only emerge at frequencies above roughly 400 Hz. (similarity 0.84)
• Interaural level differences grow with frequency and side placement (similarity 0.84)
• Low-frequency interaural level differences cue source distance and signal coherence. (similarity 0.84)
• Head intensity-shading fails below the frequency where head size reaches one-third wavelength (similarity 0.83)
• Head orientation is necessary because interaural level differences plateau off-midline (similarity 0.83)
• Humans perceive interaural level differences at frequencies where plane waves produce none (similarity 0.83)
• Head shadow attenuates sound arriving at the far ear unless the source is centered (similarity 0.82)
• Acoustic head shadow creates a better ear with higher SNR in everyday listening (similarity 0.82)
• Head separation between ears produces arrival-time and intensity cues for direction (similarity 0.82)
• Interaural level differences grow with frequency and reach up to 20 dB. (similarity 0.82)
• Binaural sound localization depends on ear-level temporal and intensity encoding efficiency (similarity 0.81)
• A 5-dB hearing asymmetry doubles the perceived interaural level difference (similarity 0.81)