reverb: Reverb & echo

In soundgen: Sound Synthesis and Acoustic Analysis

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
)

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

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.

Examples

data('speechEx', package = 'soundgen')
sr = [e-mail]
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)

## Not run: 
# 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)

## End(Not run)

soundgen documentation built on Sept. 20, 2026, 5:07 p.m.