Increasing the sound intensity by a factor of The difference in decibel between sound intensity 10 -8 W/m 2and sound intensity 10 -4 W/m 2 ( 10000 units) can be calculated as = 120 dB Example - Sound Intensity and Decibel The noise level from the fan in decibel can be calculated as = 140 dB Example - Sound Power from a FanĪ fan creates 1 W of sound power. The sound power in decibel from a source with the highest possible to hear sound power can be calculated as ġ00 W is almost the highest sound power possible to hear. Sound power from common sources - tools, fans, jets.The sound power in decibel from a source with the lowest sound hearable can be calculated as S ref - reference signal - intensity or power level (signal unit)ġ0 -12 W is normally the lowest sound power possible to hear and this value is normally used as the reference power in sound power calculations. S - signal - intensity or power level (signal unit) S = S ref 10 (L / 10) (2) Decibel Calculator If the decibel value and reference level are known the absolute signal level can be calculated by transforming (1) to Note! - the decibel value of a signal increases with 3 dB if the signal is doubled (L = 10 log (2) = 3). The signal units depends on the nature of the signal - can be W for power.Ī decibel is one-tenth of a Bel - named after Alexander Graham Bell, the inventor of the telephone. S ref = reference signal - intensity or power level (signal unit)ĭecibel is a dimensionless value of relative ratios. S = signal - intensity or power level (signal unit) The decibel level of a signal can be expressed as for amplitude ratios - root power quantities - a change in amplitude by a factor of 10 corresponds to 20 dB change in level.for power ratios - dB is defined as ten times the logarithm in base 10.the decibel express the level of a value relative to a reference value.The decibel is a logarithmic unit used to describe the ratio of a signal level - like power, intensity or amplitude - to a reference level.
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