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 Look
Ahead 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 +/-6 dB,
in 0.1dB steps. It is advisable to make minor changes, primarily as the 'loudness fine tuner'. Be careful; there is a lot
of available power here!
Silk Action:
This control adjusts the texture of the limiter when it is handling significant mid and upper midrange
program material. Higher numbered settings (clockwise) soften (or silken) the sound of the limiting at higher
frequencies, with only a slight reduction in brightness on some material but can result in a “queasy” quasi-pumping
sound on some material. The sound of limiting low frequency material (<2Khz) is largely unaffected.
Speed:
This control adjusts the speed of the peak control network, affecting the texture of the limited audio. Higher
numbered settings are faster and while louder, may create a busier sound with more intermodulation distortion.
Density:
Within the limiter algorithm are multiple networks that perform the timing, or attack/release functions.
Density is a single parameter that modifies these networks with the goal of creating added perceived loudness. This
feature allows the timing networks to be altered, for more/less processing, but also maintaining a balance of the IMD
reducing functions. Higher numbered settings increase loudness at the expense of distortion.
HF Shelf EQ:
Depending upon how the processing is set for the conventional FM signal, there may be a need to
add or remove some high frequency spectra to the final mix if there is a desire to more closely match the sound of
the Look Ahead limiter to the pre-emphasized
effect
that the conventional FM channel processing possesses. It is
recommended that this parameter be left at 0.0dB to start with, and only adjusted after careful comparison to the
conventional channel.
Bandlimiting:
Omnia-6.HDFM is capable of delivering 20kHz audio response to the HD Radio/DAB encoder. If
there is a desire to reduce the audio bandwidth, it is possible to reduce the spectrum in 2kHz increments from 20kHz
down to 12kHz. All of the filters employed for this function are phase linear.
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