the thx sound generated with scipy square waves

thxsound.py

import numpy as np
from random import uniform
from scipy.signal import square
from scipy.io import wavfile

samplerate = 44100
startlength = 8
chirplength = 4
endlength = 16

detune = 1

def distinit(v):
    return 200*((2**(1/12))**v) # distribute 0-12 on exp scale 200-400

def genchirp(f0, f1):
    signal = np.logspace(0, np.log10(2), chirplength*samplerate)-1 # log ramp
    signal = np.interp(signal, [0, 1], [f0, f1])
    signal = np.concatenate((np.repeat(f0, startlength*samplerate), signal, np.repeat(f1, endlength*samplerate)))
    signal = square(signal.cumsum() * 2 * np.pi / samplerate, np.linspace(0, 1, (startlength+chirplength+endlength)*samplerate)) # pulse wave with linearly increasing duty cycle
    return np.float32(signal)

signal = np.array([0]*((startlength+chirplength+endlength)*samplerate), dtype='float32')

targetpool = [36.71, 36.71, 73.42, 73.42, 110.00, 110.00, 146.83, 146.83, 220.00, 220.00, 293.66, 293.66, 293.66, 440.00, 440.00, 440.00, 587.33, 587.33, 587.33, 880.00, 880.00, 880.00, 1174.66, 1174.66, 1174.66, 1479.98, 1479.98, 1479.98]

for t in targetpool:
    signal += genchirp(distinit(uniform(0, 12)), t+uniform(-detune, detune))

signal /= len(targetpool)

envelope = np.concatenate((np.linspace(0, 1, 16*samplerate), np.repeat(1, 8*samplerate), np.linspace(1, 0, 4*samplerate)))
signal *= envelope

wavfile.write("audio.wav", samplerate, signal)