The A Weighting Network

The A weighting network is a frequency domain correction applied to acoustic measurements.

It implements an approximate inverse of Fletcher and Munson's 0 phon equal loudness contour, such that signals which have been filtered by the A weighting network show some correlation with perceived LOUDNESS.

The response is shown in the graph below

The response is normalised to 0 dB at 1 kiloHertz.

Values of the A weighting network's response, in deciBels, at octave band centre frequencies, are tabulated below.
63 125 250 500 1000 2000 4000 8000
-26.2 -16.2 -8.7 -3.2 0.0 1.2 1.0 -1.1


A sub-set of the A Weighting filter's poles and zeros is used to give another important weighting network, widely used in the measurement of acoustic signals;

The C Weighting Network

the magnitude frequency response of which is plotted in the figure below


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