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
Aspidistra (transmitter) seven bomb-free zones in central and southern Germany. All these announcements were false. German radio stations tried announcing "The enemy is broadcasting counterfeit instructions on our frequencies. Do not be misled by them. Here is an official announcement of the Reich authority." However, "Aspidistra" broadcasts included similar announcements, leaving the listeners confused. Although mainly intended for the military and propaganda transmissions described above, "Aspidistra" was also used during the war for some BBC European Service broadcasts to Europe on 804 kHz. After 1945, "Aspidistra" continued to be used by the BBC. Frequencies used included 1122 kHz (1945–1950), 1340 kHz (1950–1962),