specToMS_1D: Spectrogram to modulation spectrum 1D
In soundgen: Sound Synthesis and Acoustic Analysis

View source: R/modulationSpectrum_utilities.R

specToMS_1D

R Documentation

Spectrogram to modulation spectrum 1D

Description

Takes a spectrogram and returns the spectrum of each channel. The input can be an ordinary STFT spectrogram or an auditory spectrogram (a signal convolved with a bank of bandpass filters). The difference from specToMS is that, instead of taking a two-dimensional transform of the spectrogram, here the spectra are calculated independently for each frequency bin.

Usage

specToMS_1D(
  spec,
  samplingRate,
  windowLength = 250,
  step = windowLength/2,
  specMethod = c("meanSpectrum", "spectrum")
)

Arguments

`spec`	input spectrogram (numeric matrix with frequency in rows and time in columns)
`samplingRate`	for auditory spectrogram, the sampling rate of input audio; for STFT spectrograms, the number of STFT frames per second
`windowLength`, `step`	determine the resolution of modulation spectra (both in ms); this only has an effect if `specMethod = "meanSpectrum"`
`specMethod`	calls either `meanSpectrum` (faster) or `spectrum` (higher resolution)

Value

A modulation spectrum - a matrix of real values, with center frequencies of original filters in rows (kHz) and modulation frequencies in columns (Hz).

Examples

data(speechEx, package = 'soundgen')

# auditory spectrogram
as = audSpectrogram(speechEx, from = 0, to = 1,
  envelope = 'hil', nFilters = 24, step = NULL, plot = FALSE)
ms = specToMS_1D(as$filterbank_env, samplingRate = speechEx@samp.rate)
plotMS(log(ms+.01), logWarpX = c(10, 2), quantiles = NULL, ylab = 'kHz')

# ordinary STFT spectrogram
sp = spectrogram(speechEx, from = 0, to = 1, windowLength = 15, step = 0.5,
  output = 'original', plot = FALSE)
ms2 = specToMS_1D(sp, 1000 / 0.5)  # 1000/0.5 frames per s
plotMS(log(ms2+.01), quantiles = NULL, ylab = 'kHz')

## Not run: 
# full resolution
ms_spec = specToMS_1D(as$filterbank_env, samplingRate = speechEx@samp.rate,
  specMethod = 'spectrum')
plotMS(log(ms_spec+.01), logWarpX = c(10, 2), quantile = NULL, ylab = 'kHz')

## End(Not run)

soundgen documentation built on Sept. 20, 2026, 5:07 p.m.