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.
40 dB sounds twice as loud as 30 dB and 8 times as loud as 10 dB (10 to 20 to 30 to 40 = 2 x 2 x 2 = 8). Normal hearing ranges from 0 to 20 dB in all frequencies. From here on, the assumption is that you have a sensorineural hearing loss (that you have nerve damage to the inner ear).Nerve damage, unless sudden, is permanent. For conductive hearing losses, see your otolaryngologist (your ENT physician).f all of the X's (for the left ear) and all of the 0's (for the right ear) fall above the line you just drew, you have normal hearing. If anything is below that 20 dB line, you have a hearing loss. Your hearing loss is classified according to how far down the graph the marks go, and in what freqencies the loss occurs.