Nitro-. a combining form or an adjective denoting the presence of niter. Nitro-. a combining form (used also adjectively) designating certain compounds of nitrogen or of its acids, as nitrohydrochloric, nitrocalcite; also, designating the group or radical NO2, or its compounds, as nitrobenzene.
The commonly stated range of human hearing is 20 Hz to 20 kHz. Under ideal laboratory conditions, humans can hear sound as low as 12 Hz and as high as 28 kHz, though the threshold increases sharply at 15 kHz in adults, corresponding to the last auditory channel of the cochlea.
While 20 to 20,000Hz forms the absolute borders of the human hearing range, our hearing is most sensitive in the 2000 - 5000 Hz frequency range.As far as loudness is concerned, humans can typically hear starting at 0 dB.itch is measured in Hertz (Hz) and loudness is measured in decibels (dB). For a person with normal hearing, when it comes to pitch the human hearing range starts low at about 20 Hz. Thatâs about the same as the lowest pedal on a pipe organ.