Wave Python Generator

import math, wave, array, operator, winsound

BPM = 120
BEAT_VALUE = 4

NOTES = {'C': 16.35, 'C#': 17.32, 'Db': 17.32, 'D': 18.35,
        'D#': 19.45, 'Eb': 19.45, 'E': 20.60, 'F': 21.83,
        'F#': 23.12, 'Gb': 23.12, 'G': 24.50, 'G#': 25.96,
        'Ab': 25.96, 'A': 27.50, 'A#': 29.14, 'Bb': 29.14,
        'B': 30.87}

SAMPLE_RATE = 44100 # standard samples per seconds
CHANNELS = 1 # mono
BYTE_RATE = 2 # 2 bytes, 16 bit
VOLUME = 50 # percent

def create_data(d, f):
    duration = d # seconds
    frequency = f # cycles per second

    data = array.array('h') # signed short integer

    samples_per_cycle = int(SAMPLE_RATE / frequency)
    number_samples = int(SAMPLE_RATE * duration)

    for i in range(number_samples):
        sample = 32767 * float(VOLUME) / 100
        sample *= math.sin(math.pi * 2 * (i % samples_per_cycle) / samples_per_cycle)
        data.append(int(sample))

    return data

def write_wave(data, duration):
    w = wave.open('output.wav', 'w')
    w.setparams((CHANNELS, BYTE_RATE, SAMPLE_RATE, SAMPLE_RATE * duration, "NONE", "Uncompressed"))
    w.writeframes(data.tostring())
    w.close()

def getFreq(note, octave):
    return NOTES[note] * (2**octave)

def getTime(beat, multiplyer = 1):
    return (60/BPM) * (1/beat) * BEAT_VALUE * multiplyer

if __name__ == '__main__':
    data = array.array('h')
    data2 = array.array('h')
    data3 = array.array('h')

    data.extend(create_data(getTime(1), getFreq('C', 4)))
    data2.extend(create_data(getTime(1), getFreq('Bb', 4)))
    data3.extend(create_data(getTime(1), getFreq('G', 4)))

    for i in range(len(data)):
        data[i] += data2[i]
        data[i] += data3[i]

    write_wave(data, int(len(data)/SAMPLE_RATE))
    winsound.PlaySound('output.wav', winsound.SND_FILENAME)