Omnia Audio Omnia A/XE - Manual (Page 57)

Final Limiter
Omnia A/XE employs a lookahead limiter to provide absolute and precision peak control.
This limiter has been designed to minimize processing side-affects like IMD, which are
usually associated with limiters of this type. Using an innovative design that cancels inter-
modulation products before they develop, allows this limiter to sound extremely transparent.
The limiting function is derived using numerous control signals that monitor one another.
This type of peak controller is used instead of a clipper because it does not generate the
same high levels of THD as a Clipper does. THD causes added difficulties in a coded audio
system, as the harmonics generated from the clipping action, create added artifacts in the
encoder. These are especially annoying at high frequencies.
On the other hand, a lookahead limiter, yields extremely low levels of THD, although it
will create some IMD component, and this allows the audio coder to operate with minimal
sonic artifacts.
There are tradeoffs in how each of these peak controllers sound when they are set to
produce added loudness. When a clipper is pushed, the audio may appear edgier. This is
from the added harmonic content. In contrast, the lookahead limiter will appear busier, or
dense as the action of the control signal may be heard, when more limiting is applied.
Limiter Drive: Here is where the loudness versus quality is most evident! This limiter’s
adjustment range is +/-3 dB, in 0.1dB steps. It is advisable to make minor changes, primar-
ily as the ‘loudness fine tuner’. Be careful; there is a lot of available power here!
Output
The peak output level adjustment is done using the individual Left/Right output controls.
The control range is from –26dB to +6dB of gain. This level is normally set to the maximum
input level, or just below it, of the device that the Omnia A/XE is connected to.
PrOCESSING AdJUSTMENTS | 51