Download high resolution version (1200x1200, 169 KB) Second revision This was created using the following gnuplot source: kA = 7. ...

Download high resolution version (1200x1200, 169 KB) Second revision This was created using the following gnuplot source: kA = 7. ...

The A-weighting curve

dB(A) or dBA stands for decibels adjusted. It is the weighted absolute, calculated in The decibel is a dimensionless unit (like percent) that is a measure of ratios on a logarithmic scale. ...dB (SPL) (decibels referenced to the sound pressure level SPL of 20 micropascals = 0 dBA).

Equal_loudness curves

The curves are based on the psophometric curves for human hearing; the The Fletcher_Munson equal_loudness curves. ...equal_loudness contour. It is intended to approximate the level of human perception of noise. They are often used for determining the This article is about compression waves. ...sound exposure of Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ...humans. The A indicates a certain Sine waves of various frequencies; the lower waves have higher frequencies than those above. ...frequency weighting representative for the noise See: Sensitivity (electronics) Sensitivity (human) Sensitivity (tests) For sensitivity in finance, see beta coefficient This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...sensitivity of the human For an alternative meaning, see ear (botany). ...ear. In World map showing location of Europe A satellite composite image of Europe Europe is geologically and geographically a peninsula, forming the westernmost part of Eurasia. ...Europe, the dBA is generally used in all sorts of noise regulations. dB(B) and dB(C) are similar measurements using different weighting curves. The curves approximate the human ear at different loudnesses, so only one of the curves should (theoretically) be chosen for a certain measurement, depending on the absolute signal level present.

The curves are defined by the following A transfer function is a mathematical representation of the relation between the input and output of a linear time_invariant system. ...transfer functions [1] (http://www.ptpart.co.uk/noise.htm):

A

B

C

D

The k values are constants which are usually used to normalize the function to a gain of 1 (0 dB) at 1 kHz. For A_weighting, k_A ≈ 7.39705.

Note: The use of F1A_ The word line apparently derives from the Latin linum, meaning flax plant from which linen is produced; at one time, a stretched linen thread was the most reliable way to determine a straight line. ...line or HA1-receiver weighting must be indicated in parentheses as required. A sound level of 0.63 pascal 1000 Hz tone will read +90 dBA, but the same sound pressure as This article is about white noise as a scientific concept, see also: White Noise (novel), a 1985 novel by Don DeLillo. ...white noise, randomly distributed over a 3 kHz A band is a small section of the spectrum of radio communication frequencies, in which channels are usually used or set aside for the same purpose. ...band (nominally 300 to 3300 Hz), will read +82 dBA, due to the Sine waves of various frequencies; the lower waves have higher frequencies than those above. ...frequency weighting.

Manufacturers give the dBA rating for each appliance. The lower the rating the quieter the appliance when it is operating.

The A_weighted noise floor of an audio system is often several dB lower than that measured with a flat_response device. In the field of audio electronics, it is therefore sometimes used in marketing literature to make systems seem better than they are.

Synonym: The title given to this article is incorrect due to technical limitations. ...dBrn adjusted.

Source: from Federal Standard 1037C entitled Telecommunications: Glossary of Telecommunication Terms is a U.S. Federal Standard, issued by the General Services Administration pursuant to the Federal Property and Administrative Services Act of 1949, as amended. ...Federal Standard 1037C and from MIL_STD_188 is a series of U.S. military standards relating to telecommunications. ...MIL_STD_188, plot of the filtercurve from J. Wolfe, University of New South Wales (http://www.phys.unsw.edu.au/~jw/dB.html)