sihao/audiostim

Simple Python class to generate artificial auditory stimuli such as pure tones, chirps and noise.

AudioStim

Simple Python class to generate artificial auditory stimuli such as pure tones, chirps and noise.

Requirements

The dependencies are:

• numpy,
• scipy and
• matplotlib.

To install them if you do not already have them installed, you can run the following in a terminal/command window from the directory containing requirements.txt:

pip install -r requirements.txt

Usage

The example.py file describes how to create a Stimulus object:

from Stimulus import Stimulus

# Define length of stimulus in seconds and sampling rate in samples/second
length = 0.1
fs = 44100

# Initialise Stimulus object with given length and sampling rate
s = Stimulus(length, fs)

Generating the stimulus

You can choose to generate:

• a pure tone

  # Define frequency of tone
  f = 1000
  
  # Generate tone
  s.pure_tone(f)

• a frequency sweep

  # Define start and stop frequency of sweep
  start = 0
  stop = 1000
  
  # Generate frequency sweep
  s.chirp(start,stop)

• silence

  # Generate silence
  s.silence()

• white noise

  # Generate white noise
  s.noise()

Note that the methods pure_tone(), chirp(), silence() and noise() will overwrite whatever is stored as data in the object.

Adding Stimulus objects

You can add Stimulus objects with the + operator. In the example, we generate a noise stimulus and add it to a stimulus with silence.

# Generate noise and silence and add them together
fs = 44100

noise_length = 0.1
silence_length = 1


noise = Stimulus(noise_length, fs)
noise.noise()

silence = Stimulus(silence_length, fs)
silence.silence()

stim = silence + noise

Repeating a stimulus

A stimulus can be repeated with the * operator:

repeated_stim = 3 * stim

Visualising the stimulus

You can plot the waveform and the spectrogram of the stimulus using the plot_waveform() and plot_spectrogram() methods respectively:

repeated_stim.plot_waveform()
repeated_stim.plot_spectrogram()

Saving the stimulus

Stimuli can be saved into wav files using the save_wav() method:

repeated_stim.save_wav('filename.wav')

By default, stimuli are as 16-bit files, but it is possible to select 32-bit:

repeated_stim.save_wav('filename.wav', bit_depth='32')