#DECIBEL SCALE CALCULATOR PLUS#

The logarithmic decibel scale is convenient when adding signal values like sound power, pressure and others from two or more sources.īackground noise frequencies that interferes with speech. The phonetic alphabet used in international aircraft communications. Outdoor ambient sound pressure levels (dBA) in rural and urban business and industrial environments with or without limited traffic. Maximum recommended sound pressure levels in rooms like kindergartens, auditoriums, libraries, cinemas and more.Įstimate noise generated by air flow in ducts. The rules of logarithms - log 10 and log e for numbers ranging 1 to 1000. Sound pressure filters that compensates for the hearing sensed by the human ear. Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems. Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.Įngineering related topics like Beaufort Wind Scale, CE-marking, drawing standards and more. 10000 raises its level by 40 dB and so onĪ ref = amplitude level level (signal unit).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 back of the lightning calculator has instructions for use printed in black lettering.The decibel is a logarithmic unit used to describe the ratio of a signal level - like power, intensity or amplitude - to a reference level. 'USE RED SCALE FOR POWER RATIO' is written in red letters in the bottom right-hand corner of the calculator.

'USE BLACK SCALE FOR VOLTAGE OR CURRENT RATIO' is written in red letters in the bottom left-hand corner of the calculator.

#DECIBEL SCALE CALCULATOR PLUS#

The calculator has 'a scale for each input and output level in current or voltage or power, and a transmission loss or gain scale for either voltage or power ratio plus and minus 120 or 60 db.' The American Radio Relay's catalogue 'Lightning Calculators' describes the scales on this calculator as follows: The superimposed circle rotates to align desired scales on the circles. Some of the scales are written in black and others in red. There is a metal divot at the shared center that doubles as an axis of rotation for the superimposed cardboard circle. There are several sets of scales: printed around the circumference of a circle on the cardboard rectangle and printed around the partial circumference of a partial concentric circle. There are three holes through the right long edge, for placing the calculator in a binder. There is a dark orange border around the entire rectangle and the interior is white. Description The Lightning Calculator for Decibels is a cardboard rectangle.

Decibel scale calculator