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
North American Regional Broadcasting Agreement and "Clear Channel" frequencies. The only provision the FRC made addressing international concerns was that six frequencies — 690, 730, 840, 910, 960, and 1030 — were designated for exclusive Canadian use. On May 5, 1932, through an exchange of letters, the U.S. and Canada informally endorsed and expanded the 1928 standards, including recognition of Canadian use of 540 kHz. During the 1930s, Canada also began using 1510 kHz, while in 1934 the U.S. authorized two experimental high-fidelity stations on each of 1530 and 1550 kHz. By 1939, Cuban stations existed on frequencies as high as 1600 kHz. As other