Monday, December 8, 2014

Computers & Music: Isolating The Ground Loop

Hey Internet, it's been a while.  You know me, I don't write anything here unless I get inspiration.  Well I've got some.

In this installment I get to combine by technical knowledge with my other passion: music.  This servers as a simple lesson to anyone looking to use computers as part of their music setup.

I happen to know a lot of folks in the DJ biz and for the most part they're "old school".  I put that in quotes because old school DJing is pretty much vinyl and turntables.  The turntables are still around but they work with CDs now (you can still buy vinyl records and turntables though but they're really expensive these days).  With the rise of digital music in the past decade though most modern DJs uses a computer in mix.

Now before I go any further, I need to make a disclaimer.  This post is meant in no way to question what DJs are doing these days, how they do it and with what equipment.  There are a lot of DJs out there who are fine with their CD turntables.  This post is meant to give some simple advice to the guys using a computer as part of their DJ setup.

Ok, now I want you to listen to something real quick:

This is what a ground loop sounds like.  It's a high pitched whine that emanates over your audio system.  You don't even have to play anything for this to occur.

Why does this happen?  There's a perfectly good scientific explanation why but I'm not getting into that.  Here's a trick I've pulled with a couple people having this issue (fortunately they were using laptops so it was easy to explain).  All I would ask them to do is pull the power cable out of the socket.  That's right, the source of that noise is the power cable.  More specifically it comes from the ground.
There are a few solutions you can employ to get rid of the whine.  The do-it-yourself solution is to cut off the ground or try to yank it from that slot.  I really don't recommend that one but I've seen people do it.  The second solution is to use a power cable that doesn't have the ground.  Most of the replacement universal power cables come with no ground.

Chances are if you're using a desktop computer then none of these options work for you.  Well there's another solution: purchase and install a ground loop isolator.

It's pretty simple to use and it won't break your bank.  You just plug this in between your audio source and your mixer.

If you're been having this issue with your system and this entry helps you out I'd really love to know.  Leave me some responses  in the comment section.