Ear-tip insertion depth shifts canal resonance upward by several kilohertz

Evidence

For IE headphones carefully selecting the right size and shape of ear tips can achieve a reliable seal and repeatable measurements are easier to achieve. The main challenge is maintaining a constant insertion depth as this effectively changes the ear canal’s length, volume and transfer impedance (Johansen et al., 2024). The change is visible as a frequency shift in the resonance related to the length of the canal: deeper insertions will shift the resonance a few kHz higher around 8 kHz. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1719

Categorization

• DEFINE: Clarifies how insertion depth physically alters the ear canal’s effective acoustics and resonance.