Ultrasound independent Advisory Group on Non-ionising Radiation (AGNIR) produced a report in 2010, which was published by the UK Health Protection Agency (HPA). This report recommended an exposure limit for the general public to airborne ultrasound sound pressure levels (SPL) of 70 dB (at 20 kHz), and 100 dB (at 25 kHz and above). Ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is approximately 20 kilohertz (20,000
Lost Frequencies Lost Frequencies Felix De Laet (born 30 November 1993), known by his stage name Lost Frequencies, is a Belgian DJ and record producer. He is best known for his singles "Are You with Me" in 2014 and "Reality" in 2015. The name "Lost Frequencies" was first used when De Laet had used old songs, which he calls 'lost frequencies' to make remixes when he started the project. In 2014, Lost Frequencies made a remix of country artist Easton Corbin's "Are You with Me". The song had originally appeared in Corbin's second studio album, "All Over the Road", but had not