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
Australian and New Zealand television frequencies allocation issue was not fixed until the late 1990s, when the FM band was expanded to the standard full 20 MHz block. As of the mid-2010s NZ totally abandoned its VHF band for UHF channels above 25. There is a frequency offset for many DTV channels between Australia and NZ, because of historical reasons relating to the introduction of PAL. DVB-T channel allocation note Table notes : Text in "italics" means these frequencies are not currently used but set aside as a Guardband or for future use. The ABC has the highest number of transmission sites: often, but not always,