The sound of hiccups in the ears is caused by the airflow entering the middle ear tympanic cavity through the pharyngeal opening of the nasopharynx, which in turn impacts the eardrum. If there is debris-like or flaky cerumen in the external ear canal near the eardrum, it produces vibration and can also produce sound. The middle ear tympanic cavity is normally a closed cavity that communicates with the nasopharynx through the eustachian tube opening. The eustachian tube opening is normally closed and opens inadvertently during yawning or chewing to regulate the pressure inside and outside the tympanic cavity.