.modulationSpectrum: Modulation spectrum per sound

Description

Internal soundgen function.

Usage

.modulationSpectrum(
  audio,
  specSource = c("STFT", "audSpec")[1],
  windowLength = 15,
  step = 1,
  wn = "hanning",
  zp = 0,
  audSpec_pars = list(filterType = "butterworth", nFilters = 32, bandwidth = 1/24, yScale
    = "bark", dynamicRange = 120),
  msType = c("1D", "2D")[2],
  amRes = 5,
  maxDur = 5,
  specMethod = c("spec", "meanspec")[2],
  logSpec = FALSE,
  logMPS = FALSE,
  power = 1,
  normalize = TRUE,
  roughRange = c(30, 150),
  roughMean = NULL,
  roughSD = NULL,
  roughMinFreq = 1,
  amRange = c(10, 200),
  returnMS = TRUE,
  returnComplex = FALSE,
  plot = TRUE,
  savePlots = NULL,
  logWarpX = NULL,
  logWarpY = NULL,
  quantiles = c(0.5, 0.8, 0.9),
  kernelSize = 5,
  kernelSD = 0.5,
  colorTheme = c("bw", "seewave", "heat.colors", "...")[1],
  col = NULL,
  main = NULL,
  xlab = "Hz",
  ylab = "1/kHz",
  xlim = NULL,
  ylim = NULL,
  width = 900,
  height = 500,
  units = "px",
  res = NA,
  ...
)

Arguments

audio: a list returned by readAudio
specSource: 'STFT' = Short-Time Fourier Transform; 'audSpec' = a bank of bandpass filters (see audSpectrogram)
windowLength, step, wn, zp: parameters for extracting a spectrogram if specType = 'STFT'. Window length and step are specified in ms (see spectrogram). If specType = 'audSpec', these settings have no effect
audSpec_pars: parameters for extracting an auditory spectrogram if specType = 'audSpec'. If specType = 'STFT', these settings have no effect
msType: '2D' = two-dimensional Fourier transform of a spectrogram; '1D' = separately calculated spectrum of each frequency band
amRes: target resolution of amplitude modulation, Hz. If NULL, the entire sound is analyzed at once, resulting in a single roughness value (unless it is longer than maxDur, in which case it is analyzed in chunks maxDur s long). If amRes is set, roughness is calculated for windows ~1000/amRes ms long (but at least 3 STFT frames). amRes also affects the amount of smoothing when calculating amMsFreq and amMsPurity
maxDur: sounds longer than maxDur s are split into fragments, and the modulation spectra of all fragments are averaged
specMethod: the function to call when calculating the spectrum of each frequency band (only used when msType = '1D'); 'meanspec' is faster and less noisy, whereas 'spec' produces higher resolution
logSpec: if TRUE, the spectrogram is log-transformed prior to taking 2D FFT
logMPS: if TRUE, the modulation spectrum is log-transformed prior to calculating roughness
power: raise modulation spectrum to this power (eg power = 2 for ^2, or "power spectrum")
normalize: if TRUE, the modulation spectrum of each analyzed fragment maxDur in duration is separately normalized to have max = 1
roughRange: the range of temporal modulation frequencies that constitute the "roughness" zone, Hz
roughMean, roughSD: the mean (Hz) and standard deviation (semitones) of a lognormal distribution used to weight roughness estimates. If either is null, roughness is calculated simply as the proportion of spectrum within roughRange. If both roughMean and roughRange are defined, weights outside roughRange are set to 0; a very large SD (a flat weighting function) gives the same result as just roughRange without any weighting (see examples)
roughMinFreq: frequencies below roughMinFreq (Hz) are ignored when calculating roughness (ie the estimated roughness increases if we disregard very low-frequency modulation, which is often strong)
amRange: the range of temporal modulation frequencies that we are interested in as "amplitude modulation" (AM), Hz
returnMS: if FALSE, only roughness is returned (much faster). Careful with exporting the modulation spectra of a lot of sounds at once as this requires a lot of RAM
returnComplex: if TRUE, returns a complex modulation spectrum (without normalization and warping)
plot: if TRUE, plots the modulation spectrum of each sound (see plotMS)
savePlots: if a valid path is specified, a plot is saved in this folder (defaults to NA)
logWarpX, logWarpY: numeric vector of length 2: c(sigma, base) of pseudolog-warping the modulation spectrum, as in function pseudo_log_trans() from the "scales" package
quantiles: labeled contour values, % (e.g., "50" marks regions that contain 50% of the sum total of the entire modulation spectrum)
kernelSize: the size of Gaussian kernel used for smoothing (1 = no smoothing)
kernelSD: the SD of Gaussian kernel used for smoothing, relative to its size
colorTheme: black and white ('bw'), as in seewave package ('seewave'), matlab-type palette ('matlab'), or any palette from palette such as 'heat.colors', 'cm.colors', etc
col: actual colors, eg rev(rainbow(100)) - see ?hcl.colors for colors in base R (overrides colorTheme)
xlab, ylab, main, xlim, ylim: graphical parameters
width, height, units, res: parameters passed to png if the plot is saved
...: other graphical parameters passed on to filled.contour.mod and contour (see spectrogram)