Infrasound

You're sitting in the cinema and suddenly feel uneasy—even though nothing dramatic is happening on screen yet. Your ears don't consciously perceive anything, but your body reacts: your chest tightens, your neck stiffens, a diffuse fear creeps in. That's infrasound—frequencies below 20 Hz that the human ear doesn't consciously register, but which travel directly into the nervous system via bone conduction and vibrations. On set and in the edit, we work with this invisible tool to create emotional reactions before the viewer knows why they're afraid.

Practical application: Infrasound is generated by deep synthesizer layers, sub-bass below 30 Hz, or mechanical vibrations—a helicopter rotor, an exploding door, earthquake simulations. In the edit, I mix these frequencies beneath the dialogue and music levels. The trick is that no one consciously says: "I hear something deep"—instead, everyone feels an inexplicable presence. Infrasound was used deliberately in films like The Ring or Insidious to enhance the jump scare effect. The audience is already on edge before the visual horror sequence arrives. The physiological reaction—increased heart rate, sweating—is real and measurable.

Technically: We use sub-bass layers with frequencies between 5 and 20 Hz. On the film set itself, you can generate infrasound through deep drone tones or vibration boxes that run during the shoot—this gives the actors a genuine physiological baseline tension that shows in their performance. In the mix: a separate low-frequency track, controlled fading to build pressure. Important: This only works in cinemas or on good surround systems at home—phone speakers and standard laptop audio are worthless here.

The boundary is deliberate: too much infrasound becomes physically unbearable, triggering genuine panic. It's about psychological manipulation in the best sense—addressing the subconscious level without the viewer seeing through the manipulation. That's the difference between true horror and a cheap jump scare solution.