Polarity is not something you will normally hear in a natural setting. It’s purely an artifact of a edited or reproduced music. It is sometimes called the phase inversion and refers to the swapping of the positive and negative poles of a source. In other words, it means inverting both poles of the musical waveform. Though it’s true that you can swap a plus and minus, it’s mostly negative in most parts.
Every live mix, unless amplified, are usually in the right polarity. When you invert a polarity, you usually end up with an audio with harsh sibilance, blurry transients, and muttering vocals. It lowers down the quality of refined tones. However, phase inversion is still commonly used.
Photo Source: https://www.youtube.com/watch?v=Wv_RMhLu_So
What is absolute phase?
Absolute phase is a situation with an audio that you will encounter when the you connect a black terminal to a black wire lead, and a red terminal to a red wire lead. When you do so, something happens with the electrical polarity of your audio system. When you invert this, you usually end up with throwing the initial snap into the speaker cabinet and not directly to ears. This causes the sine waves, like percussion, to approach something of a square wave. Hence your ears may not be able to hear it.
How to recognize inverted polarity?
At first, it will be hard to recognize polarity. This problem is not only experienced by beginners. Even few designers can’t sometimes identify the issue. It takes, time and practice for you to be able to identify it with ease. To begin with, you need to routinely mark your recording. Some recordings have individual tracks in inverted polarity already, so be keen. When your ear learns to pick out polarity inversions, then you may not need to do the markings.
*A useful tool would be Polarity Checker*
Why invert a polarity?
When making a video and you want the sounds effects to stand out more than the dialogue, then you can use inverted polarity. To do this, you usually have to turn your center channel volume up by significant level. If this does not satisfy you, then you can try inverting the red ad black wires. Connect the black terminal to a red wire lead and the red terminal to the black wire lead. Do this either on the speaker or amp side, but never to both.
In audio, when you want to cover the issues you have with a component, then inverted polarity comes in handy. Since it gives off the blurry sound details, it can often disguise the disparity in speed within the panels. When the problem involves woofers, you can use a hybrid speaker system that uses electrostatics to invert polarity. However, when doing so, you should remember that this does not actually add detail to the audio. In fact, it even drags the sound down. The bass will be a half or so beat behind, classical music will seem distracted, and jazz will lose the “tight” feeling common in it.
What speaker design should be used?
The ideal waveform emits a right triangle that has a sharp starting rise with a slow decline back towards the zero point. Some tests proved that only very few manufacturers follow this ideal waveform and some of them are no longer used today. Many speaker designers just fail to design the speakers to be time and phase aligned. Instead, they would invert the midrange driver’s polarity in line with the woofer and tweeter in the hopes to get better sine waves. However, they forget that a musical waveform does not necessarily mean a sine wave.
It is said that if all speaker designers use the said, then they are putting a limit to how far one can create diverse sound. What people usually do to remedy this is that they use a software from proper polarity.
Whether you’re convinced that you use the natural polarity or invert it, just make sure that it will not totally distort the quality of your audio. Use inverted polarity only when it’ll add a good effect to your mix.