Algorithm Manual Revision 4

Unwrap HD
English Manual – Updated 2018-02-28 151
Unwrap HD
The UnWrap HD algorithm occupies:
►
@ Normal Sample Rate: 1/4 DSP Resource
►
@ Double Sample Rate: 2/4 DSP Resource
The inputs and outputs of this algorithm are dis-
tributed as follows:
Input Output
L
E1
E2
E3
E4
L
R R
C
LFE
SL
SR
Unwrap HD algorithm
– introduction
UnWrap HD: Professional
Stereo to 5.1 Upconversion
In a perfect world, all audio recorded over the
last fifty years would be available on multi-track
tape formulated to last for centuries. Unfortu-
nately, the world is not perfect. Where source
tapes are in a usable condition, the best way to
take full advantage of the original material is typi-
cally by performing a full remix, ideally produc-
ing one type of master for every target format.
However, reasons can exist for preferring to up-
convert instead:
►
a classic mix is too sacred to touch
►
there is not enough time or budget to do a
new mix
►
a multitrack source tape in a bad condition
►
sound effects have to be spread to 5.1 for cin-
ema presentation or HD broadcast
►
an up-converted original is requested as a
benchmark when remixing.
UnWrap HD puts the process of converting from
stereo to 5.1 in the hands of an audio profes-
sional – where it belongs. It is the world’s primary
high-resolution up-conversion processor, and
with its wealth of controls, UnWrap HD is the de
facto standard in film, post and music produc-
tion. Thanks to rigorous phase and resolution
preservation in the algorithm, up-converted ma-
terial may even be subsequently down-mixed to
stereo again with no sonic penalties. Processing
is 48 bit, and sample rates up to 96 kHz may be
used.
Unwrap HD is not a one-size-fits-all solution, but
provides a host of parameters to aid the design
of a result faithful to the original with regards to
width, timbre, spaciousness, foreground/back-
ground discrimination, and other important fac-
tors. Still, there may be situations where up-con-
version won’t provide a satisfactory result, and
where the recommendation would be perform a
new mix or forget it.
UnWrap HD comes with up-conversion presets
for the type stereo and LtRt program material
typically dealt with in broadcast, film production
and music mastering. Presets are located in Fac-
tory Bank F11, decade 3 to 6.
UnWrap™ and UnWrap™ HD
The original algorithm was called UnWrap, while
the latest version with more dialog and envel-
opment extraction functions is named UnWrap
HD. Presets generated with the original UnWrap
application can be read using UnWrap HD, and
still sound precisely like when they were created.
Presets generated with UnWrap HD, however,
cannot be loaded in UnWrap.
UnWrap HD in use
UnWrap HD measures phase, delay and spec-
tral differences between a pair of stereo chan-
nels to create a 5.1 result. For different program
material there will be different parameter settings
that best represent the original mix. For different
speaker setups, the same is true. For instance
in film production, Surround arrays produce a
more diffused sound than when using a point
source ITU R-775 speaker setup, so the level and
spectral balance of the presets should not be
regarded as set in stone. Instead, Factory pre-
sets should be used as starting points. Please
familiarize yourself with the controls and param-
eter-ranges on known material and a known 5.1
monitor system before attempting to unwrap
new stuff.
Setting up
The best practice is to monitor the outputs of
UnWrap HD through the Toolbox 5.1 (e.g. by
loading preset “5.1 Monitor Matrix”).