What is the resonant frequency of the external auditory canal?

The resonant frequency of the external auditory canal is indeed about 2700 Hz. This frequency is significant because it represents the natural frequency at which the external ear canal vibrates. Due to the tube-like structure of the external auditory canal, it acts like a resonator for sound waves, enhancing certain frequencies, particularly around its resonant frequency.

Understanding the resonant frequency is vital in hearing instrument fitting because it helps audiologists and hearing aid specialists to better tailor the frequency response of hearing aids for optimal amplification. By considering the resonant frequency, professionals can ensure that hearing aids are tuned effectively to match the natural amplification characteristics of the ear canal, leading to improved sound quality and clarity for the user.

The other options do not relate directly to the resonant frequency in a way that impacts hearing aid fitting. While the vagus nerve plays a role in various physiological functions, it is not directly connected to the concept of resonant frequency in the auditory system. The isthmus is a region in the ear canal but does not denote the frequency itself, and dismissing the importance of resonant frequency in hearing aid fitting overlooks a crucial aspect of optimizing hearing devices for users.