getSpectralEnvelope | R Documentation |
Prepares a spectral envelope for filtering a sound to add formants, lip radiation, and some stochastic component regulated by temperature. Formants are specified as a list containing time, frequency, amplitude, and width values for each formant (see examples). See vignette('sound_generation', package = 'soundgen') for more information.
getSpectralEnvelope(
nr,
nc,
formants = NA,
formantDep = 1,
formantWidth = 1,
lipRad = 6,
noseRad = 4,
mouth = NA,
mouthOpenThres = 0.2,
openMouthBoost = 0,
vocalTract = NULL,
temperature = 0.05,
formDrift = 0.3,
formDisp = 0.2,
formantDepStoch = 1,
smoothLinearFactor = 1,
formantCeiling = 2,
samplingRate = 16000,
speedSound = 35400,
smoothing = list(),
output = c("simple", "detailed")[1],
plot = FALSE,
duration = NULL,
colorTheme = c("bw", "seewave", "...")[1],
col = NULL,
xlab = "Time",
ylab = "Frequency, kHz",
...
)
nr |
the number of frequency bins = windowLength_points/2, where windowLength_points is the size of window for Fourier transform |
nc |
the number of time steps for Fourier transform |
formants |
a character string like "aaui" referring to default presets
for speaker "M1"; a vector of formant frequencies; or a list of formant
times, frequencies, amplitudes, and bandwidths, with a single value of each
for static or multiple values of each for moving formants. |
formantDep |
scale factor of formant amplitude (1 = no change relative
to amplitudes in |
formantWidth |
scale factor of formant bandwidth (1 = no change) |
lipRad |
the effect of lip radiation on source spectrum, dB/oct (the default of +6 dB/oct produces a high-frequency boost when the mouth is open) |
noseRad |
the effect of radiation through the nose on source spectrum,
dB/oct (the alternative to |
mouth |
mouth opening (0 to 1, 0.5 = neutral, i.e. no modification) (anchor format) |
mouthOpenThres |
open the lips (switch from nose radiation to lip
radiation) when the mouth is open |
openMouthBoost |
amplify the voice when the mouth is open by
|
vocalTract |
the length of vocal tract, cm. Used for calculating formant
dispersion (for adding extra formants) and formant transitions as the mouth
opens and closes. If |
temperature |
hyperparameter for regulating the amount of stochasticity in sound generation |
formDrift |
scale factor regulating the effect of temperature on the depth of random drift of all formants (user-defined and stochastic): the higher, the more formants drift at a given temperature |
formDisp |
scale factor regulating the effect of temperature on the irregularity of the dispersion of stochastic formants: the higher, the more unevenly stochastic formants are spaced at a given temperature |
formantDepStoch |
multiplication factor for the amplitude of additional formants added above the highest specified formant (0 = none, 1 = default) |
smoothLinearFactor |
regulates smoothing of formant anchors (0 to +Inf)
as they are upsampled to the number of fft steps |
formantCeiling |
frequency to which stochastic formants are calculated, in multiples of the Nyquist frequency; increase up to ~10 for long vocal tracts to avoid losing energy in the upper part of the spectrum |
samplingRate |
sampling frequency, Hz |
speedSound |
speed of sound in warm air, cm/s. Stevens (2000) "Acoustic phonetics", p. 138 |
smoothing |
a list of parameters passed to
|
output |
"simple" returns just the spectral filter, while "detailed" also returns a data.frame of formant frequencies over time (needed for internal purposes such as formant locking) |
plot |
if TRUE, produces a plot of the spectral envelope |
duration |
duration of the sound, ms (for plotting purposes only) |
colorTheme |
black and white ('bw'), as in seewave package ('seewave'), or another color theme (e.g. 'heat.colors') |
col |
actual colors, eg rev(rainbow(100)) - see ?hcl.colors for colors in base R (overrides colorTheme) |
xlab , ylab |
labels of axes |
... |
other graphical parameters passed on to |
Returns a spectral filter: a matrix with frequency bins in rows and time steps in columns. Accordingly, rownames of the output give central frequency of each bin (in kHz), while colnames give time stamps (in ms if duration is specified, otherwise 0 to 1).
# [a] with only F1-F3 visible, with no stochasticity
e = getSpectralEnvelope(nr = 512, nc = 50, duration = 300,
formants = soundgen:::convertStringToFormants('a'),
temperature = 0, plot = TRUE, col = heat.colors(150))
# image(t(e)) # to plot the output on a linear scale instead of dB
# some "wiggling" of specified formants plus extra formants on top
e = getSpectralEnvelope(nr = 512, nc = 50,
formants = c(860, 1430, 2900),
temperature = 0.1, formantDepStoch = 1, plot = TRUE)
# a schwa based on variable length of vocal tract
e = getSpectralEnvelope(nr = 512, nc = 100, formants = NA,
vocalTract = list(time = c(0, .4, 1), value = c(13, 18, 17)),
temperature = .1, plot = TRUE)
# no formants at all, only lip radiation
e = getSpectralEnvelope(nr = 512, nc = 50, lipRad = 6,
formants = NA, temperature = 0, plot = FALSE)
plot(e[, 1], type = 'l') # linear scale
plot(20 * log10(e[, 1]), type = 'l') # dB scale - 6 dB/oct
# mouth opening
e = getSpectralEnvelope(nr = 512, nc = 50,
vocalTract = 16, plot = TRUE, lipRad = 6, noseRad = 4,
mouth = data.frame(time = c(0, .5, 1), value = c(0, 0, .5)))
# scale formant amplitude and/or bandwidth
e1 = getSpectralEnvelope(nr = 512, nc = 50,
formants = soundgen:::convertStringToFormants('a'),
formantWidth = 1, formantDep = 1) # defaults
e2 = getSpectralEnvelope(nr = 512, nc = 50,
formants = soundgen:::convertStringToFormants('a'),
formantWidth = 1.5, formantDep = 1.5)
plot(as.numeric(rownames(e2)), 20 * log10(e2[, 1]),
type = 'l', xlab = 'KHz', ylab = 'dB', col = 'red', lty = 2)
points(as.numeric(rownames(e1)), 20 * log10(e1[, 1]), type = 'l')
# manual specification of formants
e3 = getSpectralEnvelope(
nr = 512, nc = 50, samplingRate = 16000, plot = TRUE,
formants = list(
f1 = list(freq = c(900, 500), amp = c(30, 35), width = c(80, 50)),
f2 = list(freq = c(1900, 2500), amp = c(25, 30), width = 100),
f3 = list(freq = 3400, amp = 30, width = 120)
))
# extra zero-pole pair (doesn't affect estimated VTL and thus the extra
# formants added on top)
e4 = getSpectralEnvelope(
nr = 512, nc = 50, samplingRate = 16000, plot = TRUE,
formants = list(
f1 = list(freq = c(900, 500), amp = c(30, 35), width = c(80, 50)),
f1.5 = list(freq = 1300, amp = -15),
f1.7 = list(freq = 1500, amp = 15),
f2 = list(freq = c(1900, 2500), amp = c(25, 30), width = 100),
f3 = list(freq = 3400, amp = 30, width = 120)
))
plot(as.numeric(rownames(e4)), 20 * log10(e3[, ncol(e3)]),
type = 'l', xlab = 'KHz', ylab = 'dB')
points(as.numeric(rownames(e4)), 20 * log10(e4[, ncol(e4)]),
type = 'l', col = 'red', lty = 2)
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