Appendix I: About Uv22 Super Cd Encoding - Apogee AD-1000 Operating Manual

AD-1000 Operating Manual
Appendix I – UV22 Super CD Encoding
Squeezing more performance from a standard CD is not a new idea. It began with adding white noise, called
dither, to the digital audio. Plain dither was followed by different flavors of dither noise, then a process called
'noise shaping' and more recently various forms of so-called 'bit mapping'. Independent listening tests confirm
that these systems either color the recordings we are trying to preserve, or compromise the audible noise floor.
Five years in the making, Apogee UV22 Super CD Encoding is an entirely different process. UV22 does its job
without sonic compromise, and without adding a sound of its own, preserving the sound stage and tonal bal-
ance of the original 20-bit source. The effects are even audible on original 16-bit recordings.
UV22 Encoding adds an inaudible, high frequency 'bias' to the digital bitstream, placing an algorithmically-gen-
erated 'clump' of energy around 22 kHz. Much as the bias on an analog tape recorder smooths out magnetic
tape recording non-linearities, UV22 silently captures resolution up to – and even beyond – 20 bits on a stan-
dard, 16-bit CD. In addition, this inaudible carrier smooths the rough edges of even the most inexpensive CD
player or external converter. UV22 makes your recordings sound better on all listening systems. Running
already-mastered 16-bit sources through a UV22 processor delivers sonic improvements that any user can real-
ize on equipment they already own.
UV22 is a very special information carrier: it is not a new flavor of dither noise. The truly unique statistical prop-
erties of UV22 guarantee a constant white noise floor, very similar in character to analog tape noise, no matter
what the input source. If you listen to the noise on a UV22 encoded recording, you can hear a stable, accurate
sound stage and faithful tonal balance more than 24dB into the noise – just as you do on analog tape. Yet the
UV22's low audible noise floor sits at the theoretical limit for a 16-bit system. Nothing is lost – but a great deal
is gained.
In listening test after listening test, mastering engineers unanimously choose UV22 over all other systems. Many
thousands of CD titles have already been mastered using Apogee UV1000 Super CD Encoders and the Apogees
AD-1000.
Beware of "Music Shaping"
Noise-shaping and bit-mapping systems modify the noise floor by changing it from a familiar white noise to one
that has been radically modified. Their proponents' theory says that the –96 dB CD noise floor is not low enough
to avoid interfering with our listening pleasure, and that our ears would prefer a big dip (about 12 dB) in the
noise floor in the 2–3 kHz area, with an accompanying HF boost of as much as 30 dB. What they forget is that
few CD releases actually approach the –96 dB noise floor: the noise of almost all sources is significantly higher
than this and swamps any of the claimed benefits. In addition, in the process of shaping the 'noise', these sys-
tems are also shaping audio information hiding in what they call noise, which results in noticeable shifts in image
and colored tonality of the music.
At Apogee, we believe the dynamic range of CD to be fine for many current applications. As a result, we don't
try to modify the noise floor. Instead, we make it transparent, allowing clear, clean audio information to be heard
up to 30 dB into the noise – just like analog. This information is captured and encoded on to CD – and can be
appreciated on any CD playback system.
What Are We Comparing?
With all the grandiose claims flying about, it would be easy to forget that well-executed 16-bit digital audio for
CD can already sound amazingly good, and enhancements must therefore be subtle at best. Sometimes a man-
ufacturer will demonstrate a CD enhancement process using two CDs: one recorded using the enhancement
process and the other without. What is not usually very clear is that the CD without the process was mastered
several years ago using older A to D converter technology, and the CD with the process had the added bene-
fit of the latest A to D conversion. In these comparisons, the converters have a much bigger bearing on the per-
ceived sound quality than the difference between the enhancement processes. If you do your own listening
evaluation, be sure to keep all the variables in mind and follow standard good engineering practices when mak-
ing comparisons – such as accurate level matching.
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