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L3-LL User Manual
25
Dithering and Noise Shaping
ing are two in plementary techniques tha rove the
udio after it antized. Each technique is nsible for the
ferent subjective quality of the noise caused by re-quantization.
Dithering alters the character of the qu more closely resemble analog hiss, rather
l quantization noise. The m ng is to
the quantization noise and th hus minimizing the non-lin istortion effects
of digital quantization noise. Th s replaces the non-linear tion sound with
r, less displeasing analog-hi
Noise Shaping psycho-acoustical of overall noise energy across the
spectrum, by taking into account th hich the ear is mo ise
reases noise level in the 1-6 , a range to which the ear is se e, while
noise level in the frequency range above 15 kHz to which the ear is les itive.
ithering and noise sh aracter and frequency content of noise,
to ou
Here’s how Dithering and Noise Shaping help maintain 3 more bits of detail: Our brains are capable of
perceiving details that are lower than the noise floor. Since quantization noise is correlated to the
signal, it effectively masks the signal is correlation by inserting random signals,
allowing our brain to distinguish signal from noise and thus perceive low level details. Noise shaping
adds even more detail by shifting noise le range, away from the desired signal.
IDR™ Dither Options
ype1
ype 1 is a wide-band dither. Type1 adds a certain amount of noise, causing a 5dB increase in
ackground noise. It completely eliminates low-level distortion and signal-dependent modulation
effects. The result is a very transparent and clean low-level sound with a high resolution. It most
resembles the steady low-level hiss of an excellent quality analog system with no digital quantization
noise.
Type1 delivers no nonlinear distortion or modulation noise at low levels, and generates minimal side
effects when used with stereo signals. It is the recommended choice for high quality mastering
applications. By combining level maximization and IDR™ processing, 16-bit audio created from 20 or
24-bit masters have an apparent resolution of 19 bits. This is an improvement of more than 18dB.
Finally, unlike other dithering engines that are designed for single-stage CD mastering, IDR™ Type 1 is
optimized for use at every processing stage, allowing for subsequent signal processing.
Appendix B - IDR™ In Depth
Dithering and Noise Shap dependent, com t imp
perceived quality of digital a has been re-qu respo
improvement of a dif
antization noise to
than digita ain effect of ditheri reduce or eliminate all correlation
between e original signal, t ear d
typical e dithering proces distor
steadie ss type noise.
ly optimizes the distribution
e frequency ranges to w st sensitive. No
Shaping dec kHz range nsitiv
increasing s sens
In short, d aping work by modifying the ch
r ears.
making it less displeasing
. Dithering breaks th
to a less audib
T
T
b