Understanding Crosstalk and How To Eliminate It

It’s 3rd grade lunch period at the local elementary school.  Kids are talking and eating at their tables.  Crosstalk is when you are talking with the kid seated across from you and then other kids start talking and next thing you know, everyone is talking and no one is listening! 

What?  Oh, you want me to explain audio crosstalk…well that’s something different…but not by much.  

Let’s take the way-back machine and jump back to elementary school.  Now, let’s sit down across from each other at one of those long cafeteria tables. As we sit there talking about sports, two other kids sit next to us.  They start talking to each other.  As long as they aren’t talking too loud, you and I can still hear each other. 

Sitting there talking, we naturally hear some of the other conversation that bleeds over into our ears.  It’s not distracting, so we think nothing of it. 

Suddenly, the two get into an argument and start yelling at each other.  I can no longer hear you clearly because your voice (audio signal) is being affected by the people next to us.  Welcome to audio crosstalk. 

Crosstalk is signal leakage from one channel or circuit to another.  Much like the two side-by-side normal conversations mentioned above, crosstalk can occur at low levels and not cause any problems.  When the crosstalk level is high, then issues such as feedback and high frequency oscillation, which increases distortion, can occur.  If the latter occurs, circuits can be burned out.

What Exactly *IS* Crosstalk?

Audio flowing through cables carries an electrical charge.  This flow of audio creates changing magnetic fields.  When these magnetic fields cut across conductors, voltages are induced into them.  This voltage in the conductor is the crosstalk.

Crosstalk can occur in all types of electronic setups.  Most commonly, it occurs through improper cabling.  Anytime a high level signal runs next to a low level signal, crosstalk is bound to happen.  For example, if an electric guitar cable is run parallel to a low level cable, a high amount of crosstalk will appear in the low level (microphone) cable.  As these cables are all coming into your system directly from the source, when you turn up the gain on the mixer, you are also increase the volume of the crosstalk feedback. 

What Can Be Done?

First, if you use any type of cable snakes, make sure those cables are only used for low levels such as microphone levels.  Anything that runs a high line level should be run outside of that snake.

Second, avoid bundling wires tightly.  I know they look pretty and neat with the little plastic wraps but if you have just one high line level cable in there, you will have problems.

Third, whenever you have to run high and low level cables into the same place, separate them from each other as much as possible.  If they must cross each other, cross the wires at a 90-degree angle.