Appendix B - IDR™ In Depth
Dithering and Noise Shaping
Dithering and Noise Shaping are two independent, complementary techniques that improve the perceived quality of digital audio after it has been
Dithering alters the character of the quantization noise to more closely resemble analog hiss, rather than digital quantization noise. The main effect of dithering is to reduce or eliminate all correlation between the quantization noise and the original signal, thus minimizing the
Noise Shaping
In short, dithering and noise shaping work by modifying the character and frequency content of noise, making it less displeasing to our ears.
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. Dithering breaks this 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 to a less audible range, away from the desired signal.
IDR™ Dither Options
Type1
Type 1 is a
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,
Finally, unlike other dithering engines that are designed for
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