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)
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)
Out[14]:
[<matplotlib.lines.Line2D at 0x1087ee990>]