ref: 4cb48d2e44c0100a0566fad95c39b851be57fa87
dir: /python/demos/demo_miditofreq.py/
#! /usr/bin/env python
from aubio import miditofreq
from numpy import arange
upsampling = 100.
midi = arange(-10, 148 * upsampling)
midi /= upsampling
freq = miditofreq(midi)
from matplotlib import pyplot as plt
ax = plt.axes()
ax.semilogy(midi, freq, '.')
ax.set_xlabel('midi note')
ax.set_ylabel('frequency (Hz)')
plt.show()