Wave file with only Python standard libraries

write_wave.py

import struct
import wave
import os
from math import sin, tau

sample_rate = 44100.0
duration = 2.0
frequency = 440.0
num_samples = int(sample_rate * duration)
bit_depth = 16
max_amplitude = 2 ** (bit_depth - 1)
gain = 0.2
phase_delta = tau * frequency / sample_rate
filename = 'A440-Hz.wav'

wave_file = wave.open(filename, 'w')
wave_file.setnchannels(1)  # mono
wave_file.setsampwidth(bit_depth // 8)  # 16-bit depth i.e. 2 bytes
wave_file.setframerate(sample_rate)

for i in range(num_samples):
    value = sin(i * phase_delta) * gain * max_amplitude
    byte_data = struct.pack('<h', int(value))
    wave_file.writeframesraw(byte_data)

wave_file.close()

print("File saved to:\n", os.getcwd() + '/' + filename)