Digital Sound & Music: Concepts, Applications, & Science, Chapter 5, last updated 6/25/2013
51
original 16-bit wave,
wave requantized at
4 bits, and error
wave
original 16-bit wave,
wave requantized at
4 bits, and error
wave with dithering
original 16-bit wave,
wave requantized at
4 bits, and error
wave with dithering
and noise shaping
Figure 5.41 Comparison of requantization without dithering, with dithering, and with dithering
and noise shaping
To examine this more closely, we can extract the noise into a separate audio file by
subtracting the original file from the requantized one. We’ve done this for both cases noise
from dither, and noise from dither and noise shaping. (The noise includes the quantization
error.) Closeups of the noise graphs are shown in Figure 5.42. What you should notice is that
dither-with-noise-shaping noise has higher frequency components than dither-only noise.
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