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
Direct Stream Digital rate. The output from a DSD recorder is a bitstream. The long-term average of this signal is proportional to the original signal. DSD uses noise shaping techniques to push quantization noise up to inaudible ultrasonic frequencies. In principle, the retention of the bitstream in DSD lets the SACD player use a basic (one-bit) DAC design with a low-order analog filter. The SACD format can deliver a dynamic range of 120 dB from 20 Hz to 20 kHz and an extended frequency response up to 100 kHz—though most current players list an upper limit of 80–90 kHz. Most professional audiologists accept