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3-32
OPERATION
Stereo Enhancer Controls
Phase Rotator determines if the phase rotator will be in-circuit. The purpose of the
phase rotator is to make voice waveforms more symmetrical. Because it can slightly
reduce the clarity and definition of program material, we recommend leaving it O
unless program material is mainly speech, where it may result in cleaner sound be-
cause it can substantially reduce the amount of gain reduction that OPTIMOD-PC's
look-ahead limiter produces on speech waveforms.
You can operate the stereo enhancer in one of two modes or "styles." The first emu-
lates the Orban 222 analog stereo enhancer, while the second mode, called Delay,
emulates a popular enhancer from another manufacturer that adds a delayed ver-
sion of the L–R signal to the original L–R to create stereo enhancement. (See Stereo
Enhancement on page 3-9 for more information.)
It is unwise to use stereo enhancement with low bitrate codecs. At low bitrates,
these codecs use various parametric techniques for encoding the spatial attributes of
the sound field. Stereo enhancement can unnecessarily stress this encoding process.
Both modes have gating that operates under two conditions.
•
The two stereo channels are close to identical in magnitude and phase.
In this case, the enhancer assumes that the program material is actually
mono and thus suppresses enhancement to prevent the enhancement
from exaggerating the undesired channel imbalance.
•
The ratio of L–R / L+R of the enhanced signal tries to exceed the threshold set by
the L-R / L+R Ratio Limit control.
In this case, the enhancer prevents further enhancement in order to pre-
vent excess L–R energy, which can increase multipath distortion.
The stereo enhancer has the following controls:
Amount sets the maximum spatial enhancement.
Enhancer In / Out bypasses the stereo enhancer. O
Stereo Enhancer Controls
Name
Amount
In / Out
Ratio Lim
Diffusion
Style
Range
0.0 ... 10.0
Out / In
70 ... 100%
Off, 0.3 ... 10.0
222 / Delay
Table 3-5: Stereo Enhancer Controls
ORBAN MODEL 1101
is equivalent to setting the
UT
UT
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