One last switch you may encounter in the input section of your mixing board is phase reverse.
This swaps pin 2 and 3 around on your connection, inverting the phase.
“Phase Reverse” may sound like a boring and geeky term, so let’s think back to mic pick up patterns.
You’ll remember we talked about different microphone pick up or polar patterns.
Take the Bi- directional/figure of 8 pattern. For example, the front of the mic is in positive phase and the rear in negative.
Flipping the phase would turn this around; in general this is not something you’d want to do.
However, American and European wiring differ in that pins 2 and 3 of the xlr cables are reversed in the US.
You may have bought a cable there and use it for UK equipment or vice versa and you’ll find that your sound is suddenly on the thin side.
Rather than getting the soldering iron out, you can just hit the phase switch and you’re good to go.
This is also very useful when you mic the bottom of a snare drum or if you want to mix a mic’d and DI’d bass together.