Articles and resources about noise measurement issues


Early Advice | Saccharomyces Beer Cafe | A-Weighting Corrections

A-Weighting Corrections

A-Weighting is a series of corrections to the frequency range to mimic the way that the ear perceives the relative loudness of sound. These weightings were originally intended to describe sound at low volume levels; however they are now generally applied for assessment of most noise levels.  This simplification can cause issues as the ear perceives sound differently at higher sound pressure levels.  Care should be taken when applying these corrections, particularly in critical situations.

For easy reference the A-Weighting corrections for whole octaves and 1/3 octaves are shown in the tables below.

Whole Octave Band
(Hz)

A-Weighting Correction
(dB)

31.5 -39.4
63 -26.2
125 -16.1
250 -8.6
500 -3.2
1000 0
2000 1.2
4000 1
8000 -1.1

1/3 Octave Band
(Hz)

A-Weighting Correction
(dB)

10 -70.4
12.5 -63.4
16 -56.7
20 -50.5
25 -44.7
31.5 -39.4
40 -34.6
50 -30.2
63 -26.2
80 -22.5
100 -19.1
125 -16.1
160 -13.4
200 -10.9
250 -8.6
315 -6.6
400 -4.8
500 -3.2
630 -1.9
800 -0.8
1000 0
1250 0.6
1600 1
2000 1.2
2500 1.3
3150 1.2
4000 1
5000 0.5
6300 -0.1
8000 -1.1
10000 -2.5
12500 -4.3
16000 -6.6
20000 -9.3