soundgen (version 1.3.2)

fade: Fade

Description

Applies fade-in and/or fade-out of variable length, shape, and steepness. The resulting effect softens the attack and release of a waveform.

Usage

fade(x, fadeIn = 1000, fadeOut = 1000, samplingRate = NULL,
  shape = c("lin", "exp", "log", "cos", "logistic")[1], steepness = 1,
  plot = FALSE)

Arguments

x

zero-centered (!) numeric vector such as a waveform

fadeIn, fadeOut

length of segments for fading in and out, interpreted as points if samplingRate = NULL and as ms otherwise (0 = no fade)

samplingRate

sampling rate of the input vector, Hz

shape

controls the type of fade function: 'lin' = linear, 'exp' = exponential, 'log' = logarithmic, 'cos' = cosine, 'logistic' = logistic S-curve

steepness

scaling factor regulating the steepness of fading curves if the shape is 'exp', 'log', or 'logistic' (0 = linear, >1 = steeper than default)

plot

if TRUE, produces an oscillogram of the waveform after fading

Value

Returns a numeric vector of the same length as input

Examples

# NOT RUN {
#' # Fading a real sound: say we want fast attack and slow release
s = soundgen(attack = 0, windowLength = 10,
             sylLen = 500, addSilence = 0)
# playme(s)
# plot(s, type = 'l')
s1 = fade(s, fadeIn = 10, fadeOut = 350,
          samplingRate = 16000, shape = 'cos')
# playme(s1)
# plot(s1, type = 'l')


# Illustration of fade shapes
x = runif(5000, min = -1, max = 1)  # make sure to zero-center input!!!
# plot(x, type = 'l')
y = fade(x, fadeIn = 1000, fadeOut = 0, plot = TRUE)
y = fade(x,
         fadeIn = 1000,
         fadeOut = 1500,
         shape = 'exp',
         plot = TRUE)
y = fade(x,
         fadeIn = 1500,
         fadeOut = 500,
         shape = 'log',
         plot = TRUE)
y = fade(x,
         fadeIn = 1500,
         fadeOut = 500,
         shape = 'log',
         steepness = 8,
         plot = TRUE)
y = fade(x,
         fadeIn = 1000,
         fadeOut = 1500,
         shape = 'cos',
         plot = TRUE)
y = fade(x,
         fadeIn = 1500,
         fadeOut = 500,
         shape = 'logistic',
         steepness = 4,
         plot = TRUE)
# }