3.
Why can’t I adjust the crossover frequencies for the limiter section, when I can for the Multiband AGC?
That’s a great question! There are actually two reasons why we designed the system this way. First: Adjusting
the frequency distribution in the AGC section will be sonically more perceptible than if we did this in the
limiter section. The reason is that the AGC sections are operating on the RMS
average
levels, and the human
ear operates as an average detector. Thus, you’ll realize more audible frequency tailoring by making the X-Over
change in the multiband AGC's. Second: We chose the crossover points for the limiters for the best division of
the audio spectrum with respect to managing the pre-emphasis boost required for FM broadcasting. Improperly
adjusted limiter crossover frequencies could really get a user into trouble, and they would not know why.
4. My station cumes a lot of women listeners, so high frequency distortion must be kept to a minimum. How
can I make sure that the high-end is truly “silky-soft?”
Omnia-6EX naturally offers a
silky-smooth
high end, but there are a few areas when you can further tame the
high frequencies if desired. Before explaining this, we wish to say that the rumor that women listeners don’t like
a bright high end may not be true! What they don’t like is a
distorted
high end. There is a huge difference
between the two. It's fine to have a nice bright high end, as long as it’s clean!
Now regarding your question: Reduce the drive to the upper two bands of the Multiband Limiter section using
the Limiter Crossover (XO) controls. Start with a reduction of 1.0dB in each band. This will help soften and
tame the high frequencies.
To improve high-end consistency, you can try
increasing
the drive to the upper two bands of the Multiband
AGC section using the AGC Crossover (XO) controls while also
decreasing
the same upper two bands in the
AGC Mixer (Mix) a similar amount.
5.
Does the Composite Clipper contaminate the Stereo Pilot or RDS/SCA spectrum?
NO! One of the advancements that we introduced in Omnia-6EX is the ability to use composite clipping with
no
effect
to the 19kHz pilot integrity. The composite clipper is designed into the stereo generator, and is
implemented a phase linear notch filter that has negligible overshoot (< 1% modulation).
After
we're finished
with the clipping function, we insert the Stereo Pilot. In essence, we clean out the area for the pilot signal before
inserting it. By doing so, all clipping artifacts are kept to a level @ -75dB below 100% modulation, or –55dB
below the pilot level. This insures no interference to the pilot detection function in those radios that measure
noise around the 19kHz region to decide when to activate the stereo blend function.
There is also a phase linear low-pass filter at 54kHz, used to remove harmonic content created by composite
clipping. This ensures that RDS and SCA signals can be utilized without interference from the action of the
composite clipper. This filter is a carry-over from the original-Omnia design, and that filter design was based
upon an older product of ours known as
The Dividend.
6.
What pre-processors would you suggest I put in front of my Omnia-6EX?
Actually none! We don’t wish to sound arrogant by saying this, but if you look closely at the different sections
of the Omnia-6, you’ll notice that we’ve already designed it into the system in the form of a very effective
broadband AGC. One possible exception to this is in the case of STL systems, where the Omnia.6 will be
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