![]() All humans naturally think of pitch in a logarithmic scale without realizing it. The decibel is a logarithmic unit used to describe the ratio of a signal level - like power or intensity - to a reference level.3:36 where they give the piano.the decibel express the level of a value relative to a reference value.S = signal - intensity or power level (signal unit) The decibel level of a signal can be expressed as S ref = reference signal - intensity or power level (signal unit)ĭecibel is a dimensionless value of relative ratios. 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 - 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 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.Sound power from common sources - tools, fans, jets.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. Maximum Sound Pressure Levels in Rooms - Maximum recommended sound pressure levels in rooms like kindergartens, auditoriums, libraries, cinemas and more.Logarithms - The rules of logarithms - log 10 and log e for numbers ranging 1 to 1000.Decibel A, B and C - Sound pressure filters that compensates for the hearing sensed by the human ear.Miscellaneous - Engineering related topics like Beaufort Wind Scale, CE-marking, drawing standards and more.Noise and Attenuation - Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems.Acoustics - Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.10000 raises its level by 40 dB and so on.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. Sound Pressure - Sound Pressure is the force of sound on a surface perpendicular to the propagation of sound.Sound Intensity, Power and Pressure Levels - Introduction to decibel, sound power, intensity and pressure.Sound Intensity - Acoustic power of sound per unit area.SIL - the Speech Interference Levels - Background noise frequencies that interferes with speech.Signals - Adding Decibels - The logarithmic decibel scale is convenient when adding signal values like sound power, pressure and others from two or more sources.Scales of Objects - The relative scale of objects.Phonetic Alphabet - The phonetic alphabet used in international aircraft communications.Outdoor Ambient Sound Pressure Levels - Outdoor ambient sound pressure levels (dBA) in rural and urban business and industrial environments with or without limited traffic.Noise generated in Air Ducts - Estimate noise generated by air flow in ducts.
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