wavegen.py

#!/usr/bin/env python

import wave, sys
import numpy as np
import scipy.signal as signal
import math
from mpmath import *

frq_tab = [261.6, 293.6, 329.6, 349.2, 392, 440, 493.8]

framerate = 44100
siglen = 100
seednum = 5

def gen_signal(frq_id, timelen):
  t = np.arange(0, timelen, 1.0/framerate)
  data = signal.chirp(t, frq_tab[frq_id], timelen, frq_tab[frq_id]) * 10000
  return data.astype(np.short).tostring()

wf = wave.open(sys.argv[1], 'wb')

wf.setnchannels(1)
wf.setsampwidth(2)
wf.setframerate(framerate)

mp.prec = siglen + 10
mp.dps = siglen + 10

num = mpf(2) ** mpf(1.0/12)
num = mpf(seednum) ** num

while num < 0.1:
  num *= 10

while num > 1:
  num /= 10

last = 1

bank = str(num)[2:]

for i in range(0, min(siglen, len(bank))):
  curr = int(bank[i])
  if curr >= 1 and curr <= 7:
    wf.writeframes(gen_signal(curr - 1, 1.0/4))
    last = curr
  else:
    wf.writeframes(gen_signal(last - 1, 1.0/4))

wf.close()