When the ear hears a loud sound and feels that the eardrum is vibrating, it may be caused by auditory allergy, Eustachian tube dysfunction, and so on. 1. Auditory allergy: It refers to a decrease in the tolerance of sound loudness, and becomes abnormally sensitive to sound stimuli, and the phenomenon of the eardrum vibrating when the ear hears a loud sound may occur, which is considered to be caused by auditory allergy. 2. Eustachian tube dysfunction: the eardrum vibrates when the ear hears loud sounds, which may also be caused by otitis media due to eustachian tube dysfunction, resulting in an imbalance of internal and external air pressure. Patients who hear loud sounds and feel their eardrums vibrating should go to a regular hospital for examination and treatment. In daily life, you should protect your ears and avoid noise and ototoxic drugs.