Infrasound
![Infrasound arrays at infrasound monitoring station in Qaanaaq, Greenland.](/Images/godic/202501/20/Infrasound_Arrays2749.jpg")
![Patent for a double bass reflex loudspeaker enclosure design intended to produce infrasonic frequencies ranging from 5 to 25 hertz, of which traditional subwoofer designs are not readily capable.](/Images/godic/202501/20/Graham_Holliman_Velocity-Coupled_Infra_Bass_speaker_design2749.jpg")
Infrasound, sometimes referred to as low-frequency sound, is sound that is lower in frequency than 20 Hz (hertz) or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. The ear is the primary organ for sensing infrasound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body.