17 Hz is one of the most experimentally documented infrasound frequencies. On 31 May 2003, a team of UK researchers conducted a mass experiment at the Purcell Room in London, exposing around 700 concert-goers to music embedded with a 17 Hz sine wave played at near the threshold of hearing. The tone was produced by an extra-long-stroke subwoofer mounted inside a seven-metre plastic sewer pipe.

The results were striking: 22% of participants reported unusual sensations when the 17 Hz tone was present — unease, sorrow, chills down the spine, nervous feelings of revulsion, and unexplained fear. The participants did not know which musical pieces contained the infrasonic tone, and the pieces were swapped between concerts to control for musical content. The experiment, called "Infrasonic," remains one of the most cited studies in infrasound research.

Some scientists have proposed that naturally occurring 17 Hz infrasound — from wind, industrial machinery, or building resonances — may be responsible for some reports of haunted locations. Here, the frequency is delivered safely as a binaural beat with a 210 Hz carrier (left: 201.5 Hz, right: 218.5 Hz). At listening volumes, it is harmless — the unsettling effects require high sound pressure levels.