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
General Mobile Radio Service and 25 kHz channel bandwidth although some "bubble pack" combo FRS/GMRS radios utilize 2.5 kHz deviation. For best compatibility of audio level, 5 kHz deviation should be used when communicating with GMRS equipment. The 4-digit decimal GMRS frequencies (shared FRS 1-7 / ICOM 9-15) are spaced 12.5 kHz from the (ICOM 1-8) GMRS frequencies, and may receive interference from other nearby stations. It may be advisable to use 12.5 kHz narrow-band (NFM) in congested areas, or avoid their use as a last resort. This second set of frequencies shows the interstitial ranges shared with the Family Radio Service services. These