9 Replies Latest reply: Feb 26, 2010 9:31 PM by samfranklin
shawnthemonster Level 1 (0 points)
ok so i have an imac (3.06 ghz intel core duo). i had a klipshe 2.1 speaker system connected with no problems. then i bought a pair of krk rokit 6's studio monitors and just have a whole lot of humming now. so far ive connected headphones to my imac and no hum.... connected my ipod to the krk's and no hum..... connected my krk's to my macbook pro (while it was plugged into the same outlet as my imac) and no hum..... bought a m-audio fast track and connected the krk's through that to my imac and still it hums.... what gives? please help. thanks


imac, Mac OS X (10.5.8)
  • Eric Wichman Level 1 (5 points)
    i'm having a similar issue with my krk roket 5's patch thru an m-audio firewire 410 connected to an imac. everything i scroll my bluetooth mouse, i hear an audible hum through the monitors. i believe it's a ground problem, so that's what i'm looking into.
  • samfranklin Level 1 (0 points)
    Shawn, I am getting a 1 KHz whine through Behringer Truth monitors using M-Audio USB Fast Track Ultra audio/midi interface with an iMac i5 27-inch with LED monitor. The whine occurs continuously from the moment I open Logic Studio or iTunes, when the output is routed through the Fast Track Ultra. The whine does not occur when I use the imac output to imac's speakers. I also get an electronic scraping noise when I use the blue tooth connected magic mouse. I have installed ferrites on the monitor speaker wires with no reduction in the whining noise or electronic scraping noise. I have also ordered the USB with ferrite collar to see if the connection between audio/midi interface and the imac is the source of the noise. I am considering a Hum-X, as well, but I am getting into serious money taking stabs at a problem for which there ought to be plenty of competent technical support. The fact that this whine is at 1 KHz and not lower suggests that I am not suffering a typical ground loop. I am a former Pro Tools user who never had a hum or whine from my Digi and G4, which I am seriously considering recomissioning so I can make music again. I am spending way too much time and money making educated guesses and trying to diagnose a problem that all but kills the utility and purpose of this new system. I too am calling on all great engineers to step up with a diagnosis and solution.
  • Got_Dibz Level 1 (0 points)
    could it be that whats causing the problem is the fast track ultra ? i am considering the krk speakers and the fast track ultra but the drivers might not be a match so im making my research and maybe thats whats causing the humming. try different household speakers on your system and see if the huming is still there .
  • acomicon Level 1 (0 points)
    samfranklin I too am using behringer B2030a Truth monitors (just got them off ebay today) connected to an Mbox2 mini and get a high frequency humming noise them moment i turn them on!

  • acomicon Level 1 (0 points)
    POSSIBLE SOLUTION: Are you guys using balanced (2-ringed) or unbalanced (single-ringed) 1/4" speaker cables?

    I realized I bought 2x unbalanced 1/4" cables today- how annoying.

    Found the possible answer on this thread:

    +"You do not have speakers, you have powered speakers. So you are not connecting a speaker, you are connecting an amplifier.+

    +Therefore you don't want speaker cables, because the signal you are sending from the MBox (preamp) to the Yamaha's amplifier input, is a line level signal, not a speaker signal.+

    +Speaker wire can be simple unshielded lamp cord, because it carries a considerable amount of power, and any interference is completely overwhelmed by the high signal level.+

    +Line level signals, however, require a shielded cable because they are tiny in power and are easily interfered with. A line level signal can be sent either with an unbalanced or a balanced cable, as long as both devices agree.+"

    Hope that helps peeps!
  • shawnthemonster Level 1 (0 points)
    so i did everything i could and could not remedy the problem. i contacted krk about the issue and they told me that its a grounding issue with the imac specifically. they told me to get a hum-x device and that will fix my problem. i will let you know if i get it and if it works....
  • samfranklin Level 1 (0 points)
    Acomicon, you are right, sir. This peep is impressed and grateful. Balanced cables are less expensive than Hum-X, and God only knows how the improper match has adversely affected my mixes. Thank you.
  • B5Ace Level 1 (0 points)
    Hey guys. I just switched to a Macbook Pro and hooked up my Behringer Truth speakers through a fast track pro external sound card. I was getting the same buzz and it was frustrating. Did some research on the maudio site and learned it was a speaker grounding issue. Main way to tell was that the headphones didn't have the buzz, but I'd try my suggestion either way. I just got some simple 3 prong to 2 prong grounding adapters. Mine were gray and u can get them at target, home depot, walmart etc...for a few bucks. I used them with the speakers and instantly they were silent. I was pumped. I'm not an electrician and don't know how safe this solution is. The website said to check w the manufacturer so ill be following up w/ them. Just wanted to share because I know how frustrating it can be...Peace.
  • samfranklin Level 1 (0 points)
    Man, you're playing with fire. My problem was caused by using speaker cables instead of audio cables from my audio/midi interface to the Truth monitors. The reason is the Truths are powered (amplified) speakers that require balanced (as opposed to unbalanced) cables. When I changed out the cables, no more hum. But the ungrounded plug removed my hum too, only I'm told that the lack of a ground could cause your monitors to blow in certain electrical events. I'm no electrician but I'm not taking the risk of removing the ground. Good luck.