Hypersonic effect Hypersonic effect The hypersonic effect is a term coined to describe a phenomenon reported in a controversial scientific study by Tsutomu Oohashi et al., which claims that, although humans cannot consciously hear ultrasound (sounds at frequencies above approximately 20 kHz), the presence or absence of those frequencies has a measurable effect on their physiological and psychological reactions. Numerous other studies have contradicted the portion of the results relating to the subjective reaction to high-frequency audio, finding that people who have "good ears" listening to Super Audio CDs and high resolution DVD-Audio recordings on high fidelity systems capable of reproducing sounds
History of broadcasting in Australia there is just a small change in format. 1920s all broadcast services allocated to a few specific frequencies, MF + LF early 1920s Class A Services low end of AM band & longwave, Class B services upper end of band, Amateurs above 1400? kHz mid 1920s AWA-influenced longwave services commenced to be switched off due to difficulties in achieving radiator efficiency late 1920s Australia commences to allocate AM radio services in the range between 1400 kHz and 1500 kHz 1926 AM restack 1930 Captain Eckersley and Radio Research Board give consideration to widespread deployment of longwave services, but eventually it