Have you ever wondered why horror movies sometimes give you an uneasy, sickening feeling, even when nothing necessarily frightening is occurring? Some directors use the anticipation of jump scares, dark scenery, or, in some cases, infrasound. Infrasound is a frequency of sound that exists in the lower ranges, usually 20 Hz or less. This tone is typically not heard by most listeners, but still picked up on, causing one to experience vibrating sensations on the eyes (causing distorted vision), headaches, and subsequently nausea.
Today in class, after learning about some frequencies we can't hear, I decided to delve further and discovered this video. Below is a link that will play infrasound.
After "listening" to this video for several minutes, I did begin to experience its effects. Although I could not hear anything, I felt a pressure and slight ache in my temples and blurred vision. The implications of these tones are that they can be utilized to manipulate the listeners to feel a certain way without knowledge of any outside force affecting them. For example, not only can they be used in horror films, but perhaps used as a means to inflict pain to individuals if the tone is low enough in frequency. From my point of view, these frequencies had effects on me, though I wonder if certain individuals are more susceptible to its effects than others.