Omnia Omnia-6EX / EXi Installation And Operation Manual

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Omnia Omnia-6EX / EXi Installation And Operation Manual Manual pdf 55 page image

Omnia-6ex Use and Operation Manual – V: 1.2055to either AC coupling in the STL system or “bounce” generated by the modulator, demodulator, or PLL of theSTL. Sometimes it’s a little of each!If you notice any “grass” exceeding the peak level of the low frequency waveforms, there could be noise orinterference getting into the system. This can occur if the RF path is noisy due to RF signal loss or if on-channel oradjacent interference is present at the receiver. Such “grass” in the form of ultrasonic overshoots can also be addedto the signal if the signal path through the STL system is not linear within the composite signal bandwidth.A simple fix for either of these two problems is to employ a composite clipper at the transmitter site. But beware:Clipping these artifacts can lead to significant audible distortion and degradation of the subcarrier region of thesignal.While the above items must be given some thought, there are many advantages to installing the processing at thestudio. If the STL link is of late design and operates as designed, superior performance can be achieved, along withhaving easy access to the processing for monitoring and adjustment.Digital STL UseIf the Digital STL employs a data reduction codec (compression), we strongly recommend that the Omnia-6EX belocated at the transmitter site. (See “Pre-Emphasis: Where To Insert” below.) If the Digital STL is a linear systemwithout data compression, we still recommend placing the processor at the transmitter site. However, the Omnia-6EX can be placed at the studio if you follow a few guidelines and are willing to accept some limitations. (See“Interfacing with a Digital STL and/or Exciter” below.) In this scenario, there also must be a provision for a stereogenerator/encoder at the transmitter (most digital exciters provide this function); therefore the composite clipper inthe Omnia-6EX cannot be used. Many exciters include some form of safety clipper or limiter as well, but these canadd distortion and unexpected overshoots if not set up properly.Monitoring PointOnce Omnia-6EX is on the air, you should select a good acoustical location for monitoring and adjusting it. We feelthat a good tuner with strong reception feeding a good set of studio monitor speakers is probably sufficient. Whilecar radio and other “typical listener situations” are important in judging the sound of Omnia-6EX against otherstations in your market, they should not be your main reference points. In addition, there should be known-accuratemodulation monitor available. If one is available, connecting an oscilloscope to the composite output of themodulation monitor will further aid in observing the overshoot performance of the system.Good, Clean Source MaterialA well-respected processing colleague once said, “Garbage in produces more garbage out!” He was not wrong. Ifyour source material is poor, or poorly performing playback equipment, you will not get maximum sonic benefitfrom your processor. Modern audio processors magnify, good or bad, whatever is present in the source material.Anomalies that you may perceive to be processing problems may in fact be source material problems that are beingexaggerated by the processing. Make sure that you start out with a good first step—good source material.Studio Microphone ProcessingThis may appear trivial, but the perceived sound of “live” voices over the air can change dramatically with differentmicrophone processing systems. There is a high probability that the sound of your on-air microphones will changewhen you change on-air processors. If you utilize microphone processing, you may have to readjust it to suit theoperation of your new processing system. Most announcers develop a “comfort zone” with respect to how theyperceive their voice on the air, especially in their headphones. When that “comfort zone” is changed or modified, acommon response is that “something is wrong” with the on-air sound. Microphone processing can be a veryimportant part of your overall station sound, but it must always work in harmony with the main on-air processing.