Mono and stereo sine .wav generation with PySoundFile

readme.md

spectra with and without dither:

http://flic.kr/p/a1Ng7L

stereo.py

"""
Testing with subtype='PCM_24' confirms that quantization distortion is from
encoding.
Waves are scaled -1 dB to prevent clipping.
"""
from __future__ import division
from soundfile import write
from numpy import transpose, pi, linspace, sin
from numpy.random import uniform

fs = 44100  # samples per second
length = 3  # seconds
f_L = 500  # Hz
f_R = 200  # Hz

t = linspace(0, length, num=fs * length, endpoint=False)
x_L = 0.891 * sin(2 * pi * f_L * t)
x_R = 0.891 * sin(2 * pi * f_R * t)

write('mono.wav', x_L, fs, subtype='PCM_16')
write('stereo.wav', transpose([x_L, x_R]), fs, subtype='PCM_16')

"""
Dither attempt:
I don't know if noise is scaled optimally, but it seems right.
"""

x = 0.891 * sin(2 * pi * f_L * t)
dither = uniform(low=-1/2**16, high=1/2**16, size=len(t))

write('dithered.wav', x + dither, fs, subtype='PCM_16')