Db a Weighting

Noise measuring Weighting filter after DIN EN 61672-1 2003-10 (DIN-IEC 651) Calculation: Frequency f → dBA and dBC Notice: Sound level meters measure the sound pressure level in dBSPL. Sound pressure is a sound field value. Frequency Hz ↓ A-weighting = dBA C-weighting = dBC Frequency Hz ↓ A-weighting = dBA C-weighting = dBC Frequency Hz ↓ A-weighting = dBA C-weighting = dBC At sound level analyzers the display (attack time t in ) is time weighted. There are different settings: Slow (S): t i n = 1000 ms Fast (F): t i n = 125 ms Pulse (I): t i n = 35 ms, t ou t = 1500 ms There is no formula for conversion from dBA to dBSPL and vice versa. The A-weighting filter curve is defined from 20 Hz to 20 kHz.

Upload
alex-hategan
Category

Documents
view
215
download
1

Embed Size (px):

description

Db a Weighting

Transcript of Db a Weighting

Noise measuring

Noise measuringWeighting filter after DIN EN 61672-1 2003-10 (DIN-IEC 651)Calculation: Frequency f dBA and dBCNotice: Sound level meters measure the sound pressure level in dBSPL. Sound pressure is a sound field value.Frequency Hz A-weighting = dBA C-weighting = dBC Frequency Hz A-weighting = dBA C-weighting = dBC Frequency Hz A-weighting = dBA C-weighting = dBC Bottom of Form

At sound level analyzers the display (attack time tin) is time weighted. There are different settings:Slow (S):tin=1000 ms

Fast (F):tin=125 ms

Pulse (I):tin=35 ms,tout=1500 ms

There is no formula for conversion from dBA to dBSPL and vice versa.

The A-weighting filter curve is defined from 20 Hz to 20 kHz.dBA: The decibel A filter is widely used. dBA roughly corresponds to the inverseof the 40 dB at 1 kHz equal-loudness curve for the human ear.Using this filter, the sound level meter is less sensitive to very high and very low frequencies.Measurements made with this scale are expressed as dBA.;dBC: The decibel C filter is practically linear over several octaves and is suitablefor subjective measurements at very high sound pressure levels.Comparing dBA and dBCRelative Response (dB)Frequency (Hz)

31.5631252505001000200040008000

dB(A)-39.5-26.2-16.2-8.7-3.201.21-1.1

dB(C)-3-0.8-0.2000-0.2-0.8-3

_1223145537.unknown

_1223145695.unknown

_1223145696.unknown

_1223145693.unknown

_1223145694.unknown

_1223145538.unknown

_1223145490.unknown

_1223145535.unknown

_1223145536.unknown