notebook/examples/Interactive Widgets/Beat Frequencies.ipynb

Exploring Beat Frequencies using the Audio Object¶

This example uses the Audio object and Matplotlib to explore the phenomenon of beat frequencies.

In [9]:

%matplotlib inline
import matplotlib.pyplot as plt
import numpy as np

In [10]:

from IPython.html.widgets import interactive
from IPython.display import Audio, display
import numpy as np

In [11]:

def beat_freq(f1=220.0, f2=224.0):
    max_time = 3
    rate = 8000
    times = np.linspace(0,max_time,rate*max_time)
    signal = np.sin(2*np.pi*f1*times) + np.sin(2*np.pi*f2*times)
    print(f1, f2, abs(f1-f2))
    display(Audio(data=signal, rate=rate))
    return signal

In [12]:

v = interactive(beat_freq, f1=(200.0,300.0), f2=(200.0,300.0))
display(v)

(220.0, 224.0, 4.0)

Your browser does not support the audio element.

In [13]:

v.kwargs

Out[13]:

{u'f1': 220.0, u'f2': 224.0}

In [14]:

f1, f2 = v.children
f1.value = 255
f2.value = 260
plt.plot(v.result[0:6000])

(255.0, 260.0, 5.0)

Your browser does not support the audio element.

Out[14]:

[<matplotlib.lines.Line2D at 0x1087ee990>]