soundgen (version 3.0.0)

reverb: Reverb & echo

Description

Adds reverberation and/or echo to a sound parametrically or based on the impulse response recorded in a particular real environment. Algorithm for parametric reverb: adds time-shifted copies of the signal weighted by a decay function. In simple terms: we specify how much and when the sound rebounds back (e.g., from the walls of a room) and add these time-shifted copies to the original - optionally, with some spectral filtering.

Usage

reverb(
  x,
  samplingRate = NULL,
  echoDelay = 200,
  echoLevel = -20,
  reverbDelay = 70,
  reverbSpread = 130,
  reverbLevel = -25,
  reverbDensity = 50,
  reverbType = "gaussian",
  IR = NULL,
  filter = list(),
  dynamicRange = 80,
  output = c("audio", "detailed"),
  play = FALSE,
  saveAudio = FALSE,
  reportEvery = NULL,
  cores = 1,
  seed = NULL
)

Value

If output = "audio", returns the processed waveform as a numeric vector. If output = "detailed", returns a list: $rvb_win = Gaussian window used to create the reverberation, $rvb = reverberation effect, $echo = echo effect, $effect = both reverb and echo mixed together, $audio = processed audio.

Arguments

x

path to a folder, one or more wav or mp3 files c('file1.wav', 'file2.mp3'), Wave object, numeric vector, or a list of Wave objects or numeric vectors

samplingRate

sampling rate of x (only needed if x is a numeric vector)

echoDelay

the delay at which the echo appears, ms

echoLevel

the rate at which the echo weakens at each repetition, dB (NULL = no echo)

reverbDelay

the time of maximum reverb density, ms

reverbSpread

standard deviation of reverb spread around time reverbDelay, ms

reverbLevel

the maximum amplitude of reverb, dB below input (NULL = no reverb)

reverbDensity

the number of echos or "voices" added

reverbType

so far only "gaussian" has been implemented

IR

recording of an impulse response in a particular environment - ideally, an instant loud click, but just clapping your hands or snapping your fingers also works as a first approximation

filter

(optional) a spectral filter to apply to the created reverb and echo (see addFormants for acceptable formats)

dynamicRange

the precision with which the reverb and echo are calculated, dB

output

"audio" = returns just the processed audio, "detailed" = returns a list with reverb window, the added reverb/echo, etc.

play

if TRUE, plays the output audio using the default player on your system. If a character string, it is passed to playme as the name of the player to use (e.g. 'aplay', 'play', 'vlc'). In case of errors, try setting another default player for playme

saveAudio

if TRUE, saves the processed audio in a subdirectory named after the function and created in the input directory (if input is a file or folder) or in the working directory

reportEvery

when processing multiple inputs, report estimated time left every reportEvery iterations (NULL = default, NA = don't report); see reportTime

cores

number of cores for parallel processing

seed

if NULL, the algorithm is stochastic; provide a positive integer for reproducibility

Examples

data('speechEx', package = 'soundgen')
sr = [email protected]
s = speechEx@left[1:16000]
# playme(s)

# parametric reverb
s_rev = reverb(s, sr)
# playme(s_rev)

# reverb of a particular real place based on its recorded IR
data('IR', package = 'soundgen')
s_ir = reverb(s, sr, IR = IR)
# playme(s_ir)

if (FALSE) {
# double echo, no reverb
s1 = reverb(s, sr, reverbLevel = NULL,
            echoDelay = c(250, 800), echoLevel = c(-15, -25))
playme(s1)
spectrogram(s1, 16000, ylim = c(0, 4))

# only reverb (indoors)
s2 = reverb(s, sr, echoDelay = NULL,
            reverbDelay = 70, reverbSpread = 130,
            reverbLevel = -20, reverbDensity = 20)
playme(s2)
spectrogram(s2, 16000, ylim = c(0, 4))

# reverb (caves)
s3 = reverb(s, sr, echoDelay = NULL,
            reverbDelay = 600, reverbSpread = 1500,
            reverbLevel = -10, reverbDensity = 100)
playme(s3)
spectrogram(s3, 16000, ylim = c(0, 4))

# both echo and reverb with high frequencies emphasized
s4 = reverb(s, sr,
            echoDelay = 250, echoLevel = -20,
            reverbDelay = 70, reverbSpread = 120,
            reverbLevel = -25, reverbDensity = 50,
            filter = list(formants = NULL, lipRad = 3))
playme(s4)
spectrogram(s4, 16000, ylim = c(0, 4))

# recorded IR
s5 = soundgen(nSyl = 2, sylLen = 250, pitch = c(500, 300))
playme(s5)
spectrogram(s5, 16000, yScale = 'ERB')
s5r = reverb(s5, 16000, IR = IR)
playme(s5r)
spectrogram(s5r, 16000, yScale = 'ERB')

# add reverb to all files in a folder, save the result
reverb('~/Downloads/temp', saveAudio = TRUE)
}