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In a broadcast facility, trying to achieve high-quality audio can be a very time-consuming task. Often, we would be very happy just to have good quality stereo audio. In spite of the complex audio processing equipment, frequently the causes of problems are very simple.

In plants that are not stereo, or in tape newsroom environments where audio is summed, if proper polarity of the audio is not observed you can experience an almost total level loss due to phase cancellation. In this case, the only audio perceptible would be the difference between the two levels. If this type of phasing problem were to be broadcast or recorded, the original content could not be recovered.

In cases where stereo audio is not summed, and the channels are not in phase, the degradation would be a combination of perceived level differences, as well as unnatural sounding audio.

Once broadcast this way, the home viewer would not likely be able to take corrective measures. However, if the program were recorded before broadcast, you could reverse one of the stereo outputs to correct the phasing problem before air.

This could be accomplished by making an adaptor, or temporarily rewiring a cable to reverse phase on one of the channels. Some master control consoles come with a “hot button” on the panel to allow the operator to reverse phase on one channel with a single button push. Obviously, the operator would need to be able to recognize the phasing problem.