soundgen (version 1.4.0)

getFormantDispersion: Get formant dispersion

Description

Internal soundgen function.

Usage

getFormantDispersion(formants, speedSound = 35400, method = c("fast",
  "accurate")[2])

Arguments

formants

a vector of formant frequencies, Hz

speedSound

speed of sound in warm air, cm/s. Stevens (2000) "Acoustic phonetics", p. 138

method

method of calculating formant dispersion: fast for simple averaging of inter-formant difference, accurate for fitting a linear regression to formant frequencies

Details

Estimates formant dispersion based on one or more formant frequencies.

Examples

# NOT RUN {
nIter = 100  # nIter = 10000 for better results
speedSound = 35400
out = data.frame(vtl = runif(nIter, 5, 70),
                 nFormants = round(runif(nIter, 1, 10)),
                 noise = runif(nIter, 0, .2),
                 vtl_est = rep(NA, nIter),
                 error = rep(NA, nIter))
for (i in 1:nIter) {
  a = 1:out$nFormants[i]
  formants = sort(speedSound * (2 * a - 1) / (4 * out$vtl[i]) * rnorm(n = length(a),
                                                                 mean = 1,
                                                                 sd = out$noise[i]))
  disp = soundgen:::getFormantDispersion(formants, method = 'fast')
  out$vtl_est[i] = speedSound / 2 / disp
  out$error[i] = (out$vtl[i] -  out$vtl_est[i]) / out$vtl[i]
}
# }
# NOT RUN {
library(ggplot2)
ggplot(out, aes(x = nFormants, y = error)) +
  geom_point(alpha = .1) +
  geom_smooth() +
  theme_bw()
ggplot(out, aes(x = noise, y = error)) +
  geom_point(alpha = .1) +
  geom_smooth() +
  theme_bw()
# }