Polarity vs Phase - Why do I need to know this? (video)

[pcrecord]

Polarity vs Phase - Why do I need to know this ?

Polarity and Phase are 2 things that anyone who does music production needs to master.
Even if you only have a home studio, as soon as you start to use more than one microphone to record or if you are doing a lot of overdubs with the same instrument and mic.

Knowing what phase and polarity is will help to avoid mistakes that can diminish the sound quality of your music.

Also many engineer use the term phase to designate polarity. This mistake can lead to misunderstanding when discussing audio with other engineers.

Let me know what you think !

 

[paulears]

I'm not really sure it causes confusion, because the context is quite clear. Yelling flip the phase of the snare, means the guy prods the button marked phase on so many mixers. Sure, he flipped polarity, and phase which is a time change in the real sense didn't change at all - but I have never known it ever cause any grief between engineers. everyone realises we just use the term badly. Phase cancellation is understood well between the two engineers as a totally different phenomenon. It's confusing to beginners, I agree, but I got to may age without ever being confused, but frequently annoyed when pulled up about it on forums.

I totally agree that it should be polarity, but probably phase does work, because when the little phase symbol or 'phase' label was used, technology did not allow us to micro delay signals. Now, the difference is important. Historically, if you did get phase cancellation and comb filtering, you knew what happened and were usually powerless to fix it! Your video is a great explanation of cancellation and tweaking, but until all those old mixers are out of use, we're stuck with two arms for the same thing. Phase, or phase - Not sure about everyone else, but I just try to avoid using both now for fear of people's reactions - "I inverted the signal with the channel strip button" works for me.

 

[bouldersound]

I think the confusion arises because with analog gear it was common practice to try to treat phase problems by inverting polarity. One setting might have been better than the other, but it wasn't necessarily "right."

 

[Boswell]

You've made a brave attempt to hold back the tide, Marco. I believe the culprits here are not the users but the equipment manufacturers. If they didn't call their polarity reversal buttons "phase" and mark them with a phi symbol, then the next generation of users would not perpetrate the anachronistic error.

Where it matters, I try to be as accurate as I can, and where there's a simple signal inversion or an interchange of + and-,, call it a change of polarity.

There's a similar problem over the confusion of whether inputs are "balanced" or "differential". Technically, balanced is just a special case of differential, but where the two inputs are always equal in amplitude and have opposite polarity. This is not unlike the case of a phase change of 180 degrees being called a polarity inversion. In professional equipment, most non-transformer inputs are differential, but happily accept balanced signals. On the other hand, a transformer requires its input signals to be balanced in order to avoid d.c. flowing through the windings and magnetising the core. A true differential input will deal correctly with signals at its + input of +3V and its - input of +5V, giving the answer -2V.

 

[pcrecord]

By stating "flip the phase" is the wrong term, I wasn't trying to set up strait anyone.. I just wanted to use the proper term and to make things clear for the beginners.
The important part of this video is to show what phasing is and what polarity is by exemples we can see and hear. This in attempt to favor awareness and experimentation.
Of course I wouln't put anyone out of a project for using the term phase instead of polarity
I also have my share of language mishaps, Ah ah !