Weiss Engineering INT204, Owner'S Manual

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experience. Notice how the noise stays untouched by the music, i.e. there is no
noise modulation.
www.weiss.ch/linked/digital-level-control/flatdither.mp3
Dithering does not stop here. More elaborate dithering schemes shape the noise
such that it is mainly present at higher frequencies where the human ear is less
sensitive. This means that the audible noise is much lower. The link below is
again the 16 bit source quantized to 8 bits with noise-shaped dithering. Probably
hard to believe that this is only an 8 bit system! Note that the music is not
distorted at all, despite the 8 bit resolution. Remember, a 16 bit system has
65 536 quantization steps while a 8 bit system has only 256 quantization steps —
a huge difference. And still, the properly dithered 8 bit system sounds great.
www.weiss.ch/linked/digital-level-control/shapeddither.mp3
This is what a properly dithered level control is capable to do. You have heard
the 8 bit version, imagine that with today’s 24 bit converters — no question that
a level control with a 24 bit wordlength easily rivals the best analog level controls.
By the way, 24 bits means 16 777 216 quantization steps.
The last example below toggles the noiseshaping dither on and off to give a
good contrast between dither/no dither versions.
www.weiss.ch/linked/digital-level-control/togglingdither.mp3
Dithering is used in many disciplines. Also see
en.wikipedia.org/wiki/Dithering
A paper on this topic (including image examples) can be found here:
www.weiss.ch/assets/content/41/white-paper-on-digital-level-control.pdf
I hope these excursions into the theory and practice of audio engineering has been
useful for you. If you would like to dive further into those issues I recommend
visiting the website of Mr. Bob Katz, a renowned mastering engineer and a Weiss
Engineering
ltd.
customer. He publishes articles on dithering and jitter and
many other topics at
www.digido.com