Ultrasound sits at the edge of human hearing — and in film, it's the territory of sonar pings, fetal monitors, and the high-pitched whine that tells an audience a piece of medical equipment is doing something serious. These 38 ultrasound clips work that whole register: pure ultrasonic high-frequency tones in clean sine waves, the rhythmic whoosh of a fetal heartbeat captured through a real ultrasound transducer, medical scanner audio with its characteristic clicks and tone shifts, and a few takes pitched lower for sci-fi work where the audience needs to feel the sound rather than just hear it.
Medical drama and hospital scenes pull the fetal-heartbeat material straight — it's one of the most emotionally direct sounds in the foley world and needs no treatment. Sci-fi editors reach for the sonar-style tones layered under spacecraft interiors and alien-detection scenes. Documentary work uses the scanner audio bed under any sequence about prenatal care or diagnostic imaging. For a horror moment, the high tone slowly sliding down a semitone behind a still shot builds dread without spelling it. Free to download with no signup or attribution.