seewave (version 2.1.6)

dBweight: 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).

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

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.

References

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

See Also

convSPL, moredB

Examples

# NOT RUN {
# 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")
# }