| Note that the sound level scale in decibels is a logarithmic rather than linear scale.A sound level change of 3 decibels is double (or half) of the previous power level. The ear registers this as just noticeable. A change in power level of 10n decibels is a power change of 10 times, and the ear judges this as only twice (or half) as loud. |
| These relationships do not hold true at all power levels or at all frequencies, as the ear is a very non-linear device.� See Fletcher-Munson hearing curves published in books on hearing. |
| Some human ears can hear sounds in the frequency range of 20Hz to 20,000Hz, however, the hearing for most people is limited to about 30Hz to 15,000 Hz. |
