ABSTRACT
In the production, recording, and transmission of stereo signals, it is not just the levels of the signals that need monitoring but also the polarity or phase relationship between them. Polarity tells whether the audio signals are “in phase” or “out of phase,” in this case meaning the positive parts of the waveform become negative, and the negative becomes positive. In analog audio, this polarity problem is an error far more common than one would imagine. In loudspeaker manufacturing, a certain proportion of units are born with reversed polarity by inadvertently swapping the voice coil leads on the soldering terminals. It is easy to go wrong in the soldering of connectors, patch bays, and so on. Most power amplifiers retain polarity of the signal from input to output; however, others do not. So just by having different amp brands powering the speaker systems may cause problems.
