When an individual produces a voice

When an individual produces a voiced sound, the vibrations within the vocal tract (larynx, nasopharyngeal column, etc.) are transmitted by bone conduction through the skull to the ear canal.90, 91, 92 In addition, when talking, the movement of the mandibular condoyle causes minute displacements of the cartilaginous portions of the ear canal.93 Together, these two sources of vibration set into motion air particles within the ear canal across the frequency spectrum. These self-generated acoustic vibrations are always present when a person vocalizes or talks, regardless of whether the ear canal is open or occluded.88 In the case of an open, unoccluded ear canal, the patient’s own voice is not perceived negatively because the sound leaks out into the environment. However, when the ear canal is occluded with an earmold/custom shell that terminates in the cartilaginous portion, the sound is trapped and unable to escape. The occluded ear canal becomes a resonant cavity, and the low-frequency SPLs, which have been boosted, pass into the cochlea because there is no other escape route available.