dBweight {seewave}

dB weightings

Description

This function returns the four most common dB weightings.

Usage

dBweight(f, dBref = NULL)

Arguments

f

frequency (in Hz).

dBref

dB reference level (by default NULL).

Details

By default, the function returns four weightings. When dBref is not NULL then the function returns the conversion from a dB reference level to four dB weighting levels.

Value

dBweight returns a list of five items corresponding to five dB weightings.

A

dB (A)

B

dB (B)

C

dB (C)

D

dB (D)

ITU

dB ITU-R 468

Note

The transfer equations used here come from Wipipedia but they were originally coming from the appendix of an international standard on the design performance of sound level meters IEC 651:1979 (Neil Glenister, pers. com.).

Author(s)

Jerome Sueur [e-mail], Zev Ross, and Andrey Anikin

References

https://en.wikipedia.org/wiki/A-weighting, https://en.wikipedia.org/wiki/ITU-R_468_noise_weighting

See Also

convSPL, moredB

Examples

# weight for a 50 Hz frequency
dBweight(f=50)
# A weight for the 1/3 Octave centre frequencies.
dBweight(f=c(20,25,31.5,40,50,63,80,100,125,160,200,250,
315,400,500,630,800,1000,1500,
1600,2000,2500,3150,4000,5000,
6300,8000,10000,12500,16000,20000))$A
# correction for a 50 Hz sound emitted at 100 dB
dBweight(f=50, dB=100)
# weighting curves plot
f <- seq(10,20000,by=10)
par(las=1)
plot(f, dBweight(f)$A, type="n", log="x",
xlim=c(10,10^5),ylim=c(-80,20),xlab="",ylab="",xaxt="n",yaxt="n")
abline(v=c(seq(10,100,by=10),seq(100,1000,by=100),
seq(1000,10000,by=1000),seq(10000,100000,by=10000),
c(100,1000,10000,100000)),col="lightgrey",lty=2)
abline(v=c(100,1000,10000,100000),col="grey")
abline(h=seq(-80, 20, 20),col="grey")
par(new=TRUE)
plot(f, dBweight(f)$A, type="l", log="x",
xlab="Frequency (Hz)", ylab="dB",lwd=2, col="blue", xlim=c(10,10^5),ylim=c(-80,20))
title(main="Acoustic weighting curves (10 Hz - 20 kHz)")
lines(x=f, y=dBweight(f)$B, col="green",lwd=2)
lines(x=f, y=dBweight(f)$C, col="red",lwd=2)
lines(x=f, y=dBweight(f)$D, col="black",lwd=2)
legend("bottomright",legend=c("dB(A)","dB(B)","dB(C)","dB(D)"),
lwd=2,col=c("blue","green","red","black"),bty="o",bg="white")