Headphone cushion leakage degrades low-frequency response but spares mid and high frequencies.

Evidence

Due to non-optimal sealing of the headphone cushions to the head or to the ear, the sound pressure partially leaks out from the space between the headphone and the ear (the pressure chamber). Such leakage influences the transfer function at low frequencies but the effect is minimal at middle and high frequencies. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 479

Categorization

• DEFINE: Introduces the pressure chamber principle that governs headphone-to-eardrum acoustics.