bgNoise: Background Noise and Soundscape Power Index

In Ruido: Soundscape Background Noise, Power, and Saturation

Background Noise and Soundscape Power Index

Description

Calculate the Background Noise and Soundscape Power values of a single audio using the methodology proposed in Towsey 2017

Usage

bgNoise(
  soundfile,
  channel = "stereo",
  timeBin = 60,
  dbThreshold = -90,
  targetSampRate = NULL,
  wl = 512,
  window = signal::hamming(wl),
  overlap = ceiling(length(window)/2),
  histbreaks = "FD",
  DCfix = TRUE
)

Arguments

soundfile	tuneR Wave object or path to a valid audio file
channel	channel where the metric values will be extract from. Available channels are: "stereo", "mono", "left" or "right". Defaults to "stereo"
timeBin	size (in seconds) of the time bin. Set to NULL to use the entire audio as a single bin. Defaults to 60
dbThreshold	minimum allowed value of dB for the spectrograms. Set to NULL to leave db values unrestricted Defaults to -90, as set by Towsey 2017
targetSampRate	desired sample rate of the audios. This argument is only used to down sample the audio. If NULL, then audio's sample rate remains the same. Defaults to NULL
wl	window length of the spectrogram. Defaults to 512
window	window used to smooth the spectrogram. Switch to signal::hanning(wl) to use hanning instead. Defaults to signal::hammning(wl)
overlap	overlap between the spectrogram windows. Defaults to wl/2 (half the window length)
histbreaks	breaks used to calculate Background Noise. Available breaks are: "FD", ⁠"Sturges⁠", "scott" and 100. Defaults to "FD". Can also be set to any numerical value to limit or increase the amount of breaks.
DCfix	if the DC offset should be removed before the metrics are calculated. Defaults to TRUE

Details

Background Noise (BGN) is an acoustic metric that measures the most common continuous baseline level of acoustic energy in a frequency window and in a time bin. It was developed by Towsey 2017 using the Lamel et al 1981 algorithm. The metric is calculated by taking the modal value of intensity values in temporal bin c in frequency window f of a recording:

BGN_{f} = mode(dB_{cf})

Soundscape Power represents a measure of signal-to-noise ratio. It measures the relation of BGN to the loudest intensities in temporal bin c in frequency window f:

POW_{f} = max(dB_{cf}) - BGN_{cf}

This mean we'll have a value of BGN and POW to each frequency window of a recording.

Value

This function returns a noise.matrix object

References

Towsey, M. W. (2017). The calculation of acoustic indices derived from long-duration recordings of the natural environment. In eprints.qut.edu.au. https://eprints.qut.edu.au/110634/
Lamel, L., Rabiner, L., Rosenberg, A., & Wilpon, J. (1981). An improved endpoint detector for isolated word recognition. IEEE Transactions on Acoustics, Speech, and Signal Processing, 29(4), 777-785 https://doi.org/10.1109/TASSP.1981.1163642

Examples

### For our main example we'll create an artificial audio with
### white noise to test its Background Noise
# We'll use the package tuneR
library(tuneR)

# Define the audio sample rate, duration and number of samples
samprate <- 12050
dur <- 60
n <- samprate * dur

# Then we generate white noise
set.seed(413)
noise <- rnorm(n)

# Linear fade-out envelope
fade <- seq(1, 0, length.out = n)

# Apply fade
signal <- noise * fade

wave <- Wave(left = signal, right = signal,
            samp.rate = samprate,
            bit = 16)

# Heres our artificial audio

wave

# Running the bgNoise function with all the default arguments
bgn <- bgNoise(wave)

# See the results
bgn

# Plot background noise and soundscape power
plot(bgn)


### This is a secondary example using audio from a real soundscape
### These audios are originated from the Escutadô Project, a project
### that records the soundscapes of the brazilian semiarid
# Getting audiofile from the online Zenodo library
dir <- paste(tempdir(), "forExample", sep = "/")
dir.create(dir)
rec <- paste0("GAL24576_20250401_", sprintf("%06d", 0), ".wav")
recDir <- paste(dir, rec , sep = "/")
url <- paste0("https://zenodo.org/records/17575795/files/",
              rec,
              "?download=1")

# Downloading the file, might take some time denpending on your internet
download.file(url, destfile = recDir, mode = "wb")

# Running the bgNoise function with all the default arguments
bgn <- bgNoise(recDir)

# Here's the result
bgn

# Plot background noise and soundscape power values
plot(bgn)

# Plot the two indices against each other
plot(bgn@values$left$BGN$BGN1, bgn@values$left$POW$POW1,
     xlab = "BGN (dB)", ylab = "POW (dB)", pch = 16)

# Now lets test and plot their correlation
BGNPOWlm <- lm(bgn@values$left$BGN$BGN1~bgn@values$left$POW$POW1)
summary(BGNPOWlm)
abline(lm(bgn@values$left$BGN$BGN1~bgn@values$left$POW$POW1), col = "red")

Ruido documentation built on April 18, 2026, 5:07 p.m.