soundgen (version 2.7.2)

addSubh: Subharmonics

Description

Internal soundgen function.

Usage

addSubh(
  rolloff,
  pitch_per_gc,
  subRatio = 2,
  subFreq = 0,
  subDep = 10,
  subWidth = 10000,
  dynamicRange = 80,
  shortestEpoch = 300
)

Value

Returns a list consisting of a list of rolloff matrices (one matrix per epoch) and a dataframe of epochs.

Arguments

rolloff

matrix of original amplitudes of each harmonic in f0 stack returned by getRolloff (columns=time, rows=frequency bins)

pitch_per_gc

vector of the same length as ncol(rolloff)): f0 in Hz, one value per glottal cycle

subRatio

a positive integer giving the ratio of f0 (the main fundamental) to g0 (a lower frequency): 1 = no subharmonics, 2 = period doubling regardless of pitch changes, 3 = period tripling, etc; subRatio overrides subFreq (anchor format)

subFreq

instead of a specific number of subharmonics (subRatio), we can specify the approximate g0 frequency (Hz), which is used only if subRatio = 1 and is adjusted to f0 so f0/g0 is always an integer (anchor format)

subDep

the depth of subharmonics relative to the main frequency component (f0), %. 0: no subharmonics; 100: g0 harmonics are as strong as the nearest f0 harmonic (anchor format)

subWidth

Width of subharmonic sidebands - regulates how rapidly g-harmonics weaken away from f-harmonics: large values like the default 10000 means that all g0 harmonics are equally strong (anchor format)

dynamicRange

dynamic range, dB. Harmonics and noise more than dynamicRange under maximum amplitude are discarded to save computational resources

shortestEpoch

minimum duration of each epoch with unchanging subharmonics regime or formant locking, in ms

Details

Adds subharmonics to the main (f0) harmonic stack, forming sidebands.

Examples

pitch_per_gc = c(400, 500, 600, 700)
rolloff = getRolloff(pitch_per_gc, rolloff = -30)
# one epoch, two subharmonics
rolloff_subh = soundgen:::addSubh(rolloff, pitch_per_gc,
  subFreq = 200, subDep = 150, shortestEpoch = 100)
# three epochs with 2/3/4 subharmonics
rolloff_subh = soundgen:::addSubh(rolloff, pitch_per_gc,
  subFreq = 200, subDep = 150, shortestEpoch = 0)