Phonophobia (from Greek φωνή - phōnē, "sound" and φόβος - phobos, "fear", also called ligyrophobia or sonophobia) is a fear of loud sounds. It can also mean a fear of voices, or a fear of one's own voice. It is a very rare phobia which is often the symptom of hyperacusis. Sonophobia can refer the hypersensitivity a patients to sound and can be part of a diagnosis of a migraine.
Ligyrophobics may be fearful of devices that can suddenly emit loud sounds, such as computer speakers or fire alarms. When operating a home theater system, computer, television, CD player, etc., they may wish to have the volume turned down all the way before doing anything that would cause the speakers to emit sound, so that once the command to produce sound is given, the user can raise the volume of the speakers to a comfortable listening level. They may avoid parades and carnivals due to the loud instruments such as drums. As festive occasions are accompanied by music of over 120 decibels, many phobics develop agoraphobia. Other ligyrophobics also steer clear of any events in which fireworks are to be let off.
Another example is watching someone blow up a balloon beyond its normal capacity. This is often an unsettling, even disturbing thing for a person with ligyrophobia to observe, as he or she anticipates a loud sound when the balloon pops. When balloons pop, two types of reactions are heavy breathing and panic attacks. The sufferer becomes anxious to get away from the source of the loud sound.