audspec: Frequency band conversion
In tlevine/tuneR: Analysis of music and speech

Description Usage Arguments Value Author(s) References See Also Examples

Perform critical band analysis (see PLP), which means the reduction of the fourier frequencies of a signal's powerspectrum to a reduced number of frequency bands in an auditory frequency scale.

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audspec(pspectrum, sr = 16000, nfilts = ceiling(hz2bark(sr/2)) + 1, 
    fbtype = c("bark", "mel", "htkmel", "fcmel"), minfreq = 0, 
    maxfreq = sr/2, sumpower = TRUE, bwidth = 1)

`pspectrum`	Output of `powspec`, matrix with the powerspectrum of each time frame in its columns.
`sr`	Sample rate of the original recording.
`nfilts`	Number of filters/frequency bins in the auditory frequency scale.
`fbtype`	Used auditory frequency scale.
`minfreq`	Lowest frequency.
`maxfreq`	Highest frequency.
`sumpower`	If `sumpower = TRUE`, the frequency scale transformation is based on the powerspectrum, if `sumpower = FALSE`, it is based on its squareroot (absolute value of the spectrum) and squared afterwards.
`bwidth`	Modify the width of the frequency bands.

`aspectrum`	Matrix with the auditory spectrum of each time frame in its columns.
`wts`	Weight matrix for the frequency band conversion.

Sebastian Krey krey@statistik.tu-dortmund.de

Daniel P. W. Ellis: http://www.ee.columbia.edu/~dpwe/resources/matlab/rastamat/

fft2melmx, fft2barkmx

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  testsound <- normalize(sine(400) + sine(1000) + square(250), "16")
  pspectrum <- powspec(testsound@left, testsound@samp.rate)
  aspectrum <- audspec(pspectrum, testsound@samp.rate)