WEISS INT203, Руководство пользователя

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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-highend.ch/computerplayback/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-highend.ch/computerplayback/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-highend.ch/computerplayback/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
1.6 Firewire vs. USB
Firewire is a peer-to-peer protocol, meaning that every device on a Firewire
network is equally capable of talking to every other device. Two video cameras
on a Firewire network can share data with each other. A Firewire audio interface
could save sound data directly to a Firewire hard drive. Your computer is just
another peer on this network, and has no inherent special status. Firewire is
always implemented in hardware, with a special controller chip on every device.
So the load it puts on your CPU is much lighter than USB communications load,
and you’re much less likely to lose any sound data just because you’re running
fifteen things at once. Specialized hardware usually makes things faster and
more reliable, and this is one of those times. But the real reason Firewire is more
reliable than USB is more fundamental than that. It’s because Firewire allows
two operating modes. One is asynchronous, similar to what USB uses. The other
is isochronous mode, and it lets a device carve out a certain dedicated amount of
bandwidth that other devices cant touch. It gets a certain number of time slices
each second all its own. The advantages for audio should be obvious: that stream
of data can just keep on flowing, and as long as there isn’t more bandwidth
demand than the wire can handle (not very likely) nothing will interfere with it.