Are two mics likely to be wired for opposite polarity from the factory?

  • Thread starter Thread starter Steenamaroo
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Steenamaroo

Steenamaroo

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I went through and checked all my mics, preamps and cables today to be sure they were wired for the same polarity.

I make my own cables, have racked a few preamps and sometimes fix mics, so it was worth checking.


Anyway, a few discrepancies were found, but my EV omnis all have opposite polarity to my oktava mk219s.
These are two mics that I know I didn't alter, at least not in that sense, so it got me thinking.


A couple of times I set up mics, realised something was wrong, and flipped the polarity, but a noob wouldn't necessarily pick up on this.

Anyway. Tell me what you know. :)
 
Two of the same make/model...or different makes?

The whole +/- Pin 2/3 thing has been going on for a long time and there are still some companies that don't stick to the +/Pin 2 scheme.

Maybe that's what you are seeing rather than a accidental mis-wire, though that's possible too.
 
Not exactly the same thing, but I've heard that JBL does something odd with their wiring that is consistent to them only.
 
miroslav said:
Two of the same make/model...or different makes?

The whole +/- Pin 2/3 thing has been going on for a long time and there are still some companies that don't stick to the +/Pin 2 scheme.

Maybe that's what you are seeing rather than a accidental mis-wire, though that's possible too.
Click to expand...

The discrepancy is between different makes.

All my (sealed+glued) EV omnis are wired one way, and both of my oktava 219s are wired another.

It's no biggie of course; I'll just wire them all for consistency, but I wondered if there was merit in announcing this for the noobs.
 
Tomm Williams said:
Not exactly the same thing, but I've heard that JBL does something odd with their wiring that is consistent to them only.
Click to expand...

Unless I'm mistaken they wire their drivers the opposite polarity of most speaker manufacturers.
 
....and anything can happen in a factory.

They don't hire people with electrical engineering degrees to do factory line work.
 
Nowadays? People with electrical engineering degrees would probably be lucky to get that job! :p

Just kidding. Point taken. :)
 
I thought that the general convention was that a positive sound pressure on the capsule would cause a positive-going voltage on pin 2.

Steenamaroo, how did you test your mics?
 
Just through comparison in pairs.

Sm7b,d112,4x635a,4xDO54,2xsm81 and an sm58 were all wired the same, so I figured they were all wired correctly.

I kept the 7b plugged in on one channel, and went through all the others one by one on another channel.

MXL990 and 2x oktava mk219 were 'wrong' from new.
RE20 was off too, but I footered with it in the past. I most likely swapped it without realising.
 
Yes, it happens, I have had:

Mics:

A Condenser mic with the capsule mounted back to front from the factory.

2 mics of the same model wired reverse polarity, but one was an older serial number so it could have been a production change.

Reverse polarity between different brands of mic.

Speakers:

JBL do indeed wire the polarity reverse to other brands, so the black connection is + when using with other brands of speaker, don't know about the newer JBL stuff.

I have also had 4 identical speakers (not JBL) where 1 of the speakers was reverse polarity to the others, which is why I always check them when wiring cabs, the speakers come out of a quad box and I bet the guy sold them to me thinking they sound like poo.

Half my older gear has pin 3 +, while all the new gear has the pin 2 + as standard, and all my old mic cables have been wired as pin 3+ but as it's the same both ends it does not matter, but again always test.

Alan.
 
Steenamaroo said:
A couple of times I set up mics, realised something was wrong, and flipped the polarity, but a noob wouldn't necessarily pick up on this.
Click to expand...

I've been meaning to ask the same thing for a while now but have never gotten around to it (i often get distracted by shinny things....) My Avantone CK7 is wired differently to every other mic in my home collection. Every other mic i own is fine with each other, it's just the CK7 i have to phase invert to get it to play nice with the others.

And your above point is scarily true. Like yourself, if i hear something's wrong i normally jump to the phase invert button and it sorts it out but, then again, i know what i'm listening for whereas a noob may not and may just assume their mics suck or, worst still, that they suck, which can really knock ones confidence :(
 
Cool. Mind is now at ease. :) Thanks.

I thought about just putting a band of tape on everything that's pin 3 hot, but I had some time on my hands.

In the end, I left the oktavas the way they were because it wasn't as convenient as I thought to rewire,
but at least I know now.
 
For the Okatavas, you could wire up some xlr barrel adapters with the cross over. Or a short dongle. May be more convenient than fiddling around with invert functions in the DAW or on preamps?

Just a thought.
 
I did think about wiring up little barrels or even patch cables, but to be honest, most of my preamps have a handy invert switch and it's pretty handy in my software too.

Cheers for the suggest, Paul.
 
Microphones with inverted wired pins are like nails with the head on the wrong side - You save them for the other side of the room. :p
 
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