Bootcamp Audio Day

import numpy as np

import pylab as plt

from scikits.audiolab import Sndfile

from scikits.audiolab import Format

#################################################

############## CREATE A SINE TONE ###############

#################################################

# set our sampling frequency

fs = 44100

# create a numpy array that can hold 3 seconds of sound

tone = np.zeros((3*fs,2))

# set frequency to 440Hz

freq = 440

# set volume to 0.3

amp = 0.3

# set values of each channel

for i in range(tone.shape[0]):

    # calculate phase value

    phaseVal = np.float(i)/np.float(fs)

    # generate tone and set volume for left and right

    tone[i][0] = np.sin(2*np.pi*freq*phaseVal)*amp

    tone[i][1] = np.sin(2*np.pi*(freq*2)*phaseVal)*amp

#################################################

########## WRITING TONES TO AUDIO FILE ##########

#################################################

# create a name for the new file

new_filename = 'tone.wav'

# Create a Sndfile instance for writing wav files @ 44100 Hz

format = Format('wav')

f = Sndfile(new_filename, 'w', format, 2, fs)

# Write out the samples to the file

f.write_frames(tone)

# close the audio file

f.close()

#################################################

############### PLOT USING PYLAB ################

#################################################

toneL = tone[:,0]

toneR = tone[:,1]

plt.subplot(211)

plt.plot(toneL[0:200])

plt.subplot(212)

plt.plot(toneR[0:200])

plt.show()