iMac 27" Static Noise through external monitors

Ive got exactly the same issue with Yamaha HS50s and 27" iMac. Just want to ask if there's any confirmation that the ground loop isolator has actually worked because I'd rather spend £5 than £300 on a new interface as I thought that was the issue.

For those using an 27" iMac to audio interface via Firewire which is then connected to a mixer and to powered monitors I found the problem was the way I was connecting the audio interface to the mixer (in my case Edirol FA-66 Firewire to Alessis Multimix).

If you use 6.3 mm to XLR cables instead of the usual 6.3mm to 6.3mm the noise is reduced almost to zero - must be something to do with the shields on XLR inputs. (Someone might have already suggested this - haven't looked through all the posts).

Hey mate

I had the same problem. It seems to be a ground loop, connected shields form these kinds of loops. If you are using balanced cables, try pulling them half way out from your monitor outputs, leaving the shield disconnected (no need to break pins or anything like this...). It worked just fine for me.

If you're not comfortable with connecting your balanced cables half way, try to use unbalanced cables and you should be fine.

Hope it helps

Cheers

Ascar

I have a 27" iMac i7 2.9ghz... I was getting hum/feedback sounds from the computer through my KRK RP8 speakers / RP10s subwoofer. My audio card is a usb Alesis io2... using xlr to 1/4" from the subwoofer to the soundcard.

Bought a Hum-X ( http://www.ebtechaudio.com/humxdes.html ) adapter off amazon, and everything is perfect now. No more noise! 🙂

I had tried balanced cables but they didn't make any difference. The only other thing that fixed it was the 3 to 2 prong adapter... but I didn't like the idea of using that. So if you're currently doing that, and it fixes your problem, this would be a safer way to do it! Hope this helps for anyone in a similar situation that I was in.

Here is the simplest and cheapest solution. Plug your powered monitors into 3-to-2 prong adapters. I bought a set of ten for a little over a dollar. Monitors have no more interference!

Had the same problem. I fixed it by plugging my monitors into a power strip connected to a seperate outlet.

Hi. Audio Awake might solve your problem.

http://www.fohlin.net/tech-stuff/audio-awake

Did any of the solutions work? I'm in the UK so it seems we already have an 'Earth' or 'Ground' on our plugs. I'm getting the same problems as you guy's though. iMac 2.5 ghz I5 8g ram intel quadcore. Lot's of interference.

I'm using a Novation Nio 2/4, Alesis monitoring and Behringer Amp. With the output going to headphones via the soundcard there is no interfence so it leads me to think it must be the amp picking the interference up, obviously from the iMac.

I bought heavy duty coax RCA's to combat this but the force is strong with this one. I specifically upgraded to Mac because they're renowned for stability for pre&post audio production and engineering. Between my logic board defecting on the first machine they sent me and now this, it's not a great start.

If any of you had luck finding the solution (minus what has already been discussed I'd be gratful to hear from you.

I can confirm using a ground loop isolator has fixed the problem for me 🙂

Thankfully a cheap fix too.

I'M STILL STRUGGLING! I'm using a 21.5" iMac, M-Audio FastTrack Pro interface, and KRK studio monitors. I'm getting the static noise through the KRK monitors ONLY when music/audio plays - the standby/on signal is perfectly clear. I've tried RCA cables, balanced XLR cables, the Ground Loop Isolator mentioned several times in this thread, plugging the monitors and computer to in separate outlets in the house, and 3-to-2 prong adapters.

Here's the kicker: The static is completely gone when I replace the iMac with my Windows laptop with the exact same connection configuration. Everything worked fine when I did that. The whole reason I got the iMac was to do recording. Do you think I have a bad iMac or am I missing something here?

Nevermind! I found the solution.

http://www.loyalmoses.com/2011/07/hope-for-others-m-audio-fast-track-pro/

Version:1.0 StartHTML:0000000105 EndHTML:0000004630 StartFragment:0000002290 EndFragment:0000004594

It’s my opinion that the problem is with the newer iMacs and in particular the Firewire 800 port. I run a normally configured recording studio and the problem recently surfaced after upgrading my iMac to a 2.7 GHz, Intel Core i5 machine.

As we all know, there is no longer support for FW 400 cables so I employ a FW400 - FW800 cable to connect external hard drives and my audio interface through a daisy chain. To lower the noise coming through the monitors, I simply inserted a 3-2-prong adapter on the iMac’s power chord (NOT A RECOMMENDED SOLUTION).

Prior to this I isolated every component of my studio setup (including hard drives, audio interface and mixing board) and no matter what, the problem goes back to the FW800 port. I also changed out the FW 800 cable and tried a smaller FW800/400 adapter with the same results: LOTS OF NOISE. The FW800 port is the only logical explanation for the source of the ground loop.

It should also be noted that there is no noise when playing iTunes MP3’s through the headphones jack. This path runs through the mixer and out to the monitors but is not connected in any way to the FW800 chain. This also reinforces that the mixer and the iMac itself is not the source of the problem.

The frustration was recently reinforced by an Apple tech that blamed my “cheap” hard drives and "faulty" house wiring. I wired the house!

Apple needs to come clean and recognized they have a problem with the FW 800 port.

one year later : Same problem with Imac 27' i7 + lexicon lambda (usb) + Mackie MR5 mk2 (jack). Terrible noise and interference - like a crazy stethoscope inside my Imac...

A very significant resolution was to change the outlet for the Mackie. Different outlet for mac and mackie.

Still have some little buz :

when I shut down the Bluetooth of trackpad and keyboard foor a usb mouse... is also better : it's micro wave after all

asap : better jack - back-ups or power filter from aps - and a bigger room to put more space between mac, mackie, cable etc...

This is not the audio interface problem nor is it a speaker problem. It's th IMAC's problem. Got this today from the maker of my audio interface.

Thank you for your email.

We get the same issue here - this is due to the Imac earthing the Audio Interface.

I suggest connecting the OPTICAL out of the Audio interface into your monitors if they have optical in.

If not, use a standard Audio Isolator between the out of your Audio interface into your Monitors.

http://www.maplin.co.uk/ground-loop-isolator-33172 £14.99

I Think Apple should sort this problem out. I don't want to put a isolator on my set up i want it to work as it says in the manual's. Spent nearly £700 on interface and monitors just to have a petty work around.

Come on apple sort this problem out.