Development of a device for generating infrasound to study its effects on health in the laboratory

Infrasound is sound at frequencies below 20Hz, the threshold of human hearing. Cars, trucks, airplanes, trains, machinery, and air systems can produce it. Infrasound can negatively affect the autonomic nervous system, which regulates vital activities like heart rate, blood pressure, respiratory frequency, etc. This disruption may cause health problems such as annoyance, dizziness, fatigue, cardiovascular disease, etc. Some studies suggest infrasound negatively affects health, but laboratory evidence are still limited. However, a difficulty in such studies is the source of infrasound, because custom speakers often cannot produce infrasound. This study aims to develop a device specially designed to generate infrasound and examine its effects on human physiology. This device includes an amplifier, low-pass filter, and a ported subwoofer with a 12-inch speaker, calibrated by a professional engineer. Calibration showed that device could produce infrasound as low as 12 Hz at 100dBA SPL with a peak of 110.6dBA. The device will generate infrasound, allowing the objective measurements in laboratory: heart rate variability (HRV), respiratory rate (RR) and electrodermal activity (EDA). This measurement will occur before, after and during exposure to infrasound, seeking to identify the physiological effects produced. In conclusion, the device effectively produce infrasound for the study of physiological measurements.