It’s nice to know what they can do, but what is XLR?
XLR is used to deliver balanced line signals across a long distance. Because the signal is balanced, it will contain less unwanted noise from outside interference.
You want to be using balanced cables, since any noise or interference will be cancelled out by the time the sound reaches your ears. Learn more about the ramifications of this and much more in TRS vs. TS! (all about cables).
Have 3 pins inside a circular connector
Are essentially the same as a TRS (Tip Ring Sleeve) cable mentioned above, but look different in their appearance.
Are suitable for both live and studio applications/situations, because they have the ability to travel long distances.
Are used to connect most microphones to their mixers or audio interfaces. Your audio interface. They also allow phantom power to be distributed to these microphones. Other cables are incapable of this feat.
You must make sure that all of your devices have balanced line inputs before using balanced XLR cables. If any signal in your chain is unbalanced, then it renders your entire chain unbalanced. In this case, your balanced XLR cables would become useless.
What makes XLR different from an unbalanced signal?
An XLR cable has 2 identical signals, plus a ground signal, where as the TS cable only has one copy of the audio signal (and therefore more susceptible to noise). As mentioned in the TRS vs. TS article, one of the signals (on an XLR cable) is basically inverted and sent completely out of phase with the other. It is flipped 180 degrees essentially.
When two signals are inverted and flipped from each-other, it creates a noise cancellation at the other end resulting in happy smiling faces for you and me 🙂
But how does it do this?
The polarity flips once on it’s way down the wires, causing the 2 signals to be out of phase with each-other.
The sound continues down the wire, and is flipped again before it reaches the end.
To cancel out any interference/noise that the wire picked up from outside forces. It does this automatically. Or auto-magically. Heh. Pretty neat huh?
So in essence, XLR cables do a great deal in protecting the sound that YOU produce!