music.adsr

music.adsr(envelope_duration=2, attack_duration=20, decay_duration=20, sustain_level=-5, release_duration=50, transition='exp', alpha=1, db_dev=-80, to_zero=1, number_of_samples=0, sonic_vector=0, sample_rate=44100)

Synthesize an ADSR envelope.

ADSR (Atack, Decay, Sustain, Release) is a very traditional loudness envelope in sound synthesis [1].

Parameters:

envelope_durationscalar

The duration of the envelope in seconds.

attack_durationscalar

The duration of the Attack in milliseconds.

decay_durationscalar

The duration of the Decay in milliseconds.

sustain_levelscalar

The Sustain level after the Decay in decibels. Usually negative.

release_durationscalar

The duration of the Release in milliseconds.

transitionstr

“exp” for exponential transitions of amplitude (linear loudness). “linear” for linear transitions of amplitude.

alphascalar or array_like

An index to make the exponential fade slower or faster [1]. Ignored it transitions=”linear” or alpha=1. If it is an array_like, it should hold three values to be used in Attack, Decay and Release.

db_devscalar or array_like

The decibels deviation to reach before using a linear fade to reach zero amplitude. If it is an array_like, it should hold two values, one for Attack and another for Release. Ignored if trans=”linear”.

to_zeroscalar or array_like

The duration in milliseconds for linearly departing from zero in the Attack and reaching the value of zero at the end of the Release. If it is an array_like, it should hold two values, one for Attack and another for Release. It’s ignored if trans=”linear”.

number_of_samplesinteger

The number of samples of the envelope. If supplied, d is ignored.

sonic_vectorarray_like

Samples for the ADSR envelope to be applied to. If supplied, d and nsamples are ignored.

sample_rateinteger

The sample rate.

Returns:

asndarray

A numpy array where each value is a value of the envelope for the PCM samples if sonic_vector is 0. If sonic_vector is input, ad is the sonic vector with the ADSR envelope applied to it.

See also

tremolo

An oscillation of loudness.

loud

A loudness transition.

fade

A fade in or fade out.

Notes

Cite the following article whenever you use this function.

References

[1]

Fabbri, Renato, et al. “Musical elements in the discrete-time representation of sound.” arXiv preprint arXiv:abs/1412.6853 (2017)

Examples

>>> write_wav_mono(note_with_vibrato() * adsr())
>>> s = horizontal_stack([note_with_vibrato() *
...                       adsr(attack_duration=i, release_duration=j)
...                       for i, j in zip([6, 50, 300], [100, 10, 200])])
>>> s = horizontal_stack([adsr(A=i, R=j, sonic_vector=note_with_vibrato())
...                       for i, j in zip([6, 15, 100], [2, 2, 20])])
>>> envelope = adsr(d=440, A=10e3, D=0, R=5e3)