Is speaker hum normal?

As my post title suggests no matter what I do I have a slight "hum" from my speakers.
 
This is only noticeable when I have no music playing, so I suppose my question is, Is there something wrong causing "hum" or is this normal?
 
I put this down to using cheap gear in the past but I have upgraded quite a bit of my gear recently but the "hum" is still there.
 
Should a studio set up be completely silent when nothing is playing?
 

Jeff Evans
Yes a studio setup should be perfectly silent when no music is playing. Anything less is unacceptable in my opinion!
 
What is your interface. What are your monitors etc.. How are your speakers connected etc... There might be something you can do in terms of linking those two that could eliminate hum. Using balanced lines etc. Possible earth loop hum might be present etc...
 
 

Thanks Jeff, That's what I thought.
My audio interface is an m-audio fasttrack. I know this is a cheap and cheerful interface but could that be the cause?
I just got a pair of JBL LRS308 monitors but I have them connected using a breakout cable (mini jack - 2 x 1/4 jacks) is that balanced? (excuse my ignorance) 
 
Should a better interface with 2 xlr outs yield better results?

Jeff, you are a legend! Tell me you didn't just draw this out on my behalf?
 
Gonna try this. Thanks!!

Jeff's drawing may help if you have a problem ground loop between the interface and the amplifier.
 
Here's the thing - ground loops are not bad, and in fact they are virtually unavoidable. The problem really stems from some very poor design/manufacturing choices made by companies that haven't read the AES standards for interconnections yet... well, or ancient Bell and BBC documents (the ancients are stealing our ideas!)

Before you make up new cables may I suggest a simple test to find the problem?
Disconnect the amplifier inputs and crank the amplifier all the way up and listen - do you hear hum, or just white noise? If you hear hum then there is a problem between the interface and the amplifier, and Jeff's cable will probably solve it.
 
If not then the problem exists elsewhere, so you want to add gear back in, one link at a time. So now connect the interface to the amplifier, but leave the rest of the interface connections disconnected. Still no hum? Now add the rest of the interface connections, one at a time. If it turns out that you get hum after adding two more connections then disconnect the first one and see if the hum goes away.
 
I recently had a problem where I only had hum when I had both left and right line inputs connected to a Presonus Firebox. Following that test procedure I discovered a bad connection is one of my cables. A couple minutes with the soldering iron solved it.

One last thought (at the risk of repeating myself) DO NOT, UNDER ANY CIRCUMSTANCES, USE ANY TRICK THAT DEFEATS THE SAFETY GROUND!!!!!! Sorry, but this is an only wives tale that still floats around the internet from time to time.... so I figured I'd be proactive<G>!

Power line noise is annoying, but it is usually quite easy to resolve, once you find the source(s). Please let us know how it turns out.

And if you are looking for some additional reading, the top documents on this topic include (among others):
Dennis Bohn's Rane Note #110 - a classic, well regarded paper that covers the topic well!
Bill Whitlock's Troubleshooting Guide, and App Notes on Interconnections and Hum and Buzz (actually, everything on their web site!)
There are many others, but these will get you started<G>!

I love a happy ending!

Sounds like you were bitten by the dreaded "Pin-1" problem on your Fast Track.
It is quite simple to fix pin-1 problems on balanced inputs and outputs. It is nearly impossible to fix them yourself on single-ended ports, and sadly Firewire and USB fall into that category. Using local power can help if the device is designed well, it may not help if the designer disregarded the rules<G>!

USB is just as susceptible to the Pin-1 problem as any other connection...
 
In fact you'd be amazed at just how badly one can muck up any interface!!