Sound¶

class aud.Sound¶

Sound objects are immutable and represent a sound that can be played simultaneously multiple times. They are called factories because they create reader objects internally that are used for playback.

ADSR(attack, decay, sustain, release)¶

Attack-Decay-Sustain-Release envelopes the volume of a sound. Note: there is currently no way to trigger the release with this API.

Parameters:	attack (float) – The attack time in seconds. decay (float) – The decay time in seconds. sustain (float) – The sustain level. release (float) – The release level.
Returns:	The created `Sound` object.
Return type:	`Sound`

accumulate(additive=False)¶

Accumulates a sound by summing over positive input differences thus generating a monotonic sigal. If additivity is set to true negative input differences get added too, but positive ones with a factor of two. Note that with additivity the signal is not monotonic anymore.

Parameters:	additive – Whether the accumulation should be additive or not.
Returns:	The created `Sound` object.
Return type:	`Sound`

addSound(sound)¶

Adds a new sound to a sound list.

Parameters:	sound (`Sound`) – The sound that will be added to the list.

Note

You can only add a sound to a sound list.

binaural()¶

convolver()

Creates a binaural sound using another sound as source. The original sound must be mono

Parameters:	hrtfs – An HRTF set. source (`Source`) – An object representing the source position of the sound. threadPool (`ThreadPool`) – A thread pool used to parallelize convolution.
Returns:	The created `Sound` object.
Return type:	`Sound`

buffer(data, rate)¶

Creates a sound from a data buffer.

Parameters:	data (numpy.ndarray) – The data as two dimensional numpy array. rate (double) – The sample rate.
Returns:	The created `Sound` object.
Return type:	`Sound`

cache()¶

Caches a sound into RAM. This saves CPU usage needed for decoding and file access if the underlying sound reads from a file on the harddisk, but it consumes a lot of memory.

Returns:	The created `Sound` object.
Return type:	`Sound`

Note

Only known-length factories can be buffered.

Warning

Raw PCM data needs a lot of space, only buffer short factories.

convolver()¶

Creates a sound that will apply convolution to another sound.

Parameters:	impulseResponse (`ImpulseResponse`) – The filter with which convolve the sound. threadPool (`ThreadPool`) – A thread pool used to parallelize convolution.
Returns:	The created `Sound` object.
Return type:	`Sound`

data()¶

Retrieves the data of the sound as numpy array.

Returns:	A two dimensional numpy float array.
Return type:	`numpy.ndarray`

Note

Best efficiency with cached sounds.

delay(time)¶

Delays by playing adding silence in front of the other sound’s data.

Parameters:	time (float) – How many seconds of silence should be added before the sound.
Returns:	The created `Sound` object.
Return type:	`Sound`

envelope(attack, release, threshold, arthreshold)¶

Delays by playing adding silence in front of the other sound’s data.

Parameters:	attack (float) – The attack factor. release (float) – The release factor. threshold (float) – The general threshold value. arthreshold (float) – The attack/release threshold value.
Returns:	The created `Sound` object.
Return type:	`Sound`

fadein(start, length)¶

Fades a sound in by raising the volume linearly in the given time interval.

Parameters:	start (float) – Time in seconds when the fading should start. length (float) – Time in seconds how long the fading should last.
Returns:	The created `Sound` object.
Return type:	`Sound`

Note

Before the fade starts it plays silence.

fadeout(start, length)¶

Fades a sound in by lowering the volume linearly in the given time interval.

Parameters:	start (float) – Time in seconds when the fading should start. length (float) – Time in seconds how long the fading should last.
Returns:	The created `Sound` object.
Return type:	`Sound`

Note

After the fade this sound plays silence, so that the length of the sound is not altered.

file(filename)¶

Creates a sound object of a sound file.

Parameters:	filename (string) – Path of the file.
Returns:	The created `Sound` object.
Return type:	`Sound`

Warning

If the file doesn’t exist or can’t be read you will not get an exception immediately, but when you try to start playback of that sound.

filter(b, a = (1))¶

Filters a sound with the supplied IIR filter coefficients. Without the second parameter you’ll get a FIR filter. If the first value of the a sequence is 0 it will be set to 1 automatically. If the first value of the a sequence is neither 0 nor 1, all filter coefficients will be scaled by this value so that it is 1 in the end, you don’t have to scale yourself.

Parameters:	b (sequence of float) – The nominator filter coefficients. a (sequence of float) – The denominator filter coefficients.
Returns:	The created `Sound` object.
Return type:	`Sound`

highpass(frequency, Q=0.5)¶

Creates a second order highpass filter based on the transfer function H(s) = s^2 / (s^2 + s/Q + 1)

Parameters:	frequency (float) – The cut off trequency of the highpass. Q (float) – Q factor of the lowpass.
Returns:	The created `Sound` object.
Return type:	`Sound`

join(sound)¶

Plays two factories in sequence.

Parameters:	sound (`Sound`) – The sound to play second.
Returns:	The created `Sound` object.
Return type:	`Sound`

Note

The two factories have to have the same specifications (channels and samplerate).

length¶: The sample specification of the sound as a tuple with rate and channel count.

limit(start, end)¶

Limits a sound within a specific start and end time.

Parameters:	start (float) – Start time in seconds. end (float) – End time in seconds.
Returns:	The created `Sound` object.
Return type:	`Sound`

list()¶

Creates an empty sound list that can contain several sounds.

Parameters:	random (int) – wether the playback will be random or not.
Returns:	The created `Sound` object.
Return type:	`Sound`

loop(count)¶

Loops a sound.

Parameters:	count (integer) – How often the sound should be looped. Negative values mean endlessly.
Returns:	The created `Sound` object.
Return type:	`Sound`

Note

This is a filter function, you might consider using Handle.loop_count instead.

lowpass(frequency, Q=0.5)¶

Creates a second order lowpass filter based on the transfer function H(s) = 1 / (s^2 + s/Q + 1)

Parameters:	frequency (float) – The cut off trequency of the lowpass. Q (float) – Q factor of the lowpass.
Returns:	The created `Sound` object.
Return type:	`Sound`

mix(sound)¶

Mixes two factories.

Parameters:	sound (`Sound`) – The sound to mix over the other.
Returns:	The created `Sound` object.
Return type:	`Sound`

Note

The two factories have to have the same specifications (channels and samplerate).

mutable()¶

Creates a sound that will be restarted when sought backwards. If the original sound is a sound list, the playing sound can change.

Returns:	The created `Sound` object.
Return type:	`Sound`

pingpong()¶

Plays a sound forward and then backward. This is like joining a sound with its reverse.

Returns:	The created `Sound` object.
Return type:	`Sound`

pitch(factor)¶

Changes the pitch of a sound with a specific factor.

Parameters:	factor (float) – The factor to change the pitch with.
Returns:	The created `Sound` object.
Return type:	`Sound`

Note

This is done by changing the sample rate of the underlying sound, which has to be an integer, so the factor value rounded and the factor may not be 100 % accurate.

Note

This is a filter function, you might consider using Handle.pitch instead.

rechannel(channels)¶

Rechannels the sound.

Parameters:	channels (int) – The new channel configuration.
Returns:	The created `Sound` object.
Return type:	`Sound`

resample(rate, high_quality)¶

Resamples the sound.

Parameters:	rate (double) – The new sample rate. high_quality (bool) – When true use a higher quality but slower resampler.
Returns:	The created `Sound` object.
Return type:	`Sound`

reverse()¶

Plays a sound reversed.

Returns:	The created `Sound` object.
Return type:	`Sound`

Note

The sound has to have a finite length and has to be seekable. It’s recommended to use this only with factories with fast and accurate seeking, which is not true for encoded audio files, such ones should be buffered using cache() before being played reversed.

Warning

If seeking is not accurate in the underlying sound you’ll likely hear skips/jumps/cracks.

sawtooth(frequency, rate=48000)¶

Creates a sawtooth sound which plays a sawtooth wave.

Parameters:	frequency (float) – The frequency of the sawtooth wave in Hz. rate (int) – The sampling rate in Hz. It’s recommended to set this value to the playback device’s samling rate to avoid resamping.
Returns:	The created `Sound` object.
Return type:	`Sound`

silence()¶

Creates a silence sound which plays simple silence.

Returns:	The created `Sound` object.
Return type:	`Sound`

sine(frequency, rate=48000)¶

Creates a sine sound which plays a sine wave.

Parameters:	frequency (float) – The frequency of the sine wave in Hz. rate (int) – The sampling rate in Hz. It’s recommended to set this value to the playback device’s samling rate to avoid resamping.
Returns:	The created `Sound` object.
Return type:	`Sound`

specs¶: The sample specification of the sound as a tuple with rate and channel count.

square(frequency, rate=48000)¶

Creates a square sound which plays a square wave.

Parameters:	frequency (float) – The frequency of the square wave in Hz. rate (int) – The sampling rate in Hz. It’s recommended to set this value to the playback device’s samling rate to avoid resamping.
Returns:	The created `Sound` object.
Return type:	`Sound`

sum()¶

Sums the samples of a sound.

Returns:	The created `Sound` object.
Return type:	`Sound`

threshold(threshold = 0)¶

Makes a threshold wave out of an audio wave by setting all samples with a amplitude >= threshold to 1, all <= -threshold to -1 and all between to 0.

Parameters:	threshold (float) – Threshold value over which an amplitude counts non-zero.
Returns:	The created `Sound` object.
Return type:	`Sound`

triangle(frequency, rate=48000)¶

Creates a triangle sound which plays a triangle wave.

Parameters:	frequency (float) – The frequency of the triangle wave in Hz. rate (int) – The sampling rate in Hz. It’s recommended to set this value to the playback device’s samling rate to avoid resamping.
Returns:	The created `Sound` object.
Return type:	`Sound`

volume(volume)¶

Changes the volume of a sound.

Parameters:	volume (float) – The new volume..
Returns:	The created `Sound` object.
Return type:	`Sound`

Note

Should be in the range [0, 1] to avoid clipping.

Note

This is a filter function, you might consider using Handle.volume instead.

write(filename, rate, channels, format, container, codec, bitrate, buffersize)¶

Writes the sound to a file.

Parameters:

filename (string) – The path to write to.
rate (int) – The sample rate to write with.
channels (int) – The number of channels to write with.
format (int) – The sample format to write with.
container (int) – The container format for the file.
codec (int) – The codec to use in the file.
bitrate (int) – The bitrate to write with.
buffersize (int) – The size of the writing buffer.

Sound¶

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